Integrated Strategies in Architecture (Technologies of Architecture)

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Author: Joan Zunde | Hocine Bougdah

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Integrated Strategies in Architecture

Integrated Strategies in Architecture introduces students aiming at careers in the building design professions to the concepts and technologies underlying the design process. Working towards developing a sound grasp of the purpose of buildings, the technology available and the specialisms that contribute, the book: • • •

presents a holistic view of the design process; bridges the gap between number-crunching and the assembly of buildings; and places current design as part of an evolutionary process, referring to historic as well as contemporary models.

Throughout, the text discusses the means by which client requirements, site conditions, financial and legal considerations and other influences can be identified and how integrated techniques can be applied to obtain the optimum solution in design. The chapters emphasise the importance of applying a spectrum of technologies to the production of successful buildings, covering: • • • • • • •

space planning; colour theory; communication; management; aesthetics; structures; and environment control.

This key text has a wide relevance to students of architecture and architectural technology, through to students of cognate disciplines such as construction management and building surveying, and to practitioners.

Joan Zunde is an architect who has taught design procedures and technology to students on a variety of courses for many years and is the author of several design books. Hocine Bougdah is Principal Lecturer in Architecture, School of Architecture, University College for the Creative Arts at Canterbury, Kent.

Technologies of Architecture Editor: Joan Zunde

Technologies of Architecture is an introductory textbook series providing a coherent framework to the architectural design process in a practical and applied way. This series forms an essential suite of books for students of architectural technology, architecture, building surveying and construction. Integrated Strategies in Architecture is the first and introductory volume.

Advisory board Michael Ashley Mark Kennet Stephen Pretlove Peter Smith Norman Wienand

Forthcoming titles Volume 2: Environment, Technology and Sustainability Stephen Sharples, Hocine Bougdah and Peter F. Smith Volume 3: Materials, Specification and Detailing Norman Wienand Volume 4: Practice, Management and Responsibility Volume 5: History, Performance and Conservation

Te c h n o l o g i e s o f A r c h i t e c t u r e VOLUME 1

Integrated Strategies in Architecture Joan Zunde and Hocine Bougdah Illustrations by Hocine Bougdah, Anya Sutton Joan Zunde and Peter Zunde

First published 2006 by Taylor & Francis 2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN Simultaneously published in the USA and Canada by Taylor & Francis 270 Madison Ave, New York, NY 10016

Taylor & Francis is an imprint of the Taylor & Francis Group, an informa business

© 2006 Joan Zunde and Hocine Bougdah This edition published in the Taylor & Francis e-Library, 2006. “To purchase your own copy of this or any of Taylor & Francis or Routledge’s collection of thousands of eBooks please go to www.eBookstore.tandf.co.uk.” All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. Every effort has been made to ensure that the advice and information in this book is true and accurate at the time of going to press. However, neither the publisher nor the authors can accept any legal responsibility or liability for any errors or omissions that may be made. In the case of drug administration, any medical procedure or the use of technical equipment mentioned within this book, you are strongly advised to consult the manufacturer’s guidelines.

British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data Zunde, J.M. (Joan M.), 1928– Integrated strategies in architecture / Joan Zunde and Hocine Bougdah. – 1st ed. p. cm. – (Technologies of architecture) Includes bibliographical references. ISBN 0-415-36083-8 (hb : alk. paper) – ISBN 0-415-36084-6 (pb : alk. paper) – ISBN 0-203-79942-9 (eb) 1. Architectural design. 2. Architectural practice. I. Bougdah, Hocine. II. Title. III. Series. NA2750.Z66 2006 720.68'4–dc22 2005028145

ISBN10 0-415-36083-8 (hbk) ISBN10 0-415-36084-6 (pbk) ISBN10 0-203-79942-9 (ebk)

ISBN13 978-0-415-36083-8 (hbk) ISBN13 978-0-415-36084-5 (pbk) ISBN13 978-0-203-79942-0 (ebk)

The authors dedicate this book to the generations of students from whom they have learned so much.

Acknowledgements Appreciation is expressed to the following people and organisations without whom the book could not have been written:

• • • •

David Cheetham, who had the idea; The Advisory Panel; The team at Taylor & Francis, especially Caroline Mallinder, Georgina Johnson, Andrew Watts and Alex Lazarou, whose generous support has been invaluable; and Francesca Berriman and Elizabeth Brookfield at CIAT for their interest.

The following individuals and bodies who have permitted drawings of their buildings or adaptations of their drawings to be reproduced:

• • • • • • • • • • •

Fondation Le Corbusier, represented in GB by DACS; Foster and Partners; Gehry Partners; The Hayward Gallery; Father Stephen Hoy; Longmans, Publishers, for permission to reuse drawings originally prepared by Peter Zunde and published in Design Procedures IV and Design Technology V by J.M. Zunde; Cesar Pelli and Associates; Richard Rogers Partnership; El Fundaçio Mies Van der Rohe; The Frank Lloyd Wright Foundation; and Sheffield Hallam University and Will Delaney, Gemma Hickling and Matthew Rowe.

The colleagues and friends who have been unfailingly patient and our families, for their infinite tolerance and encouragement. Hocine Bougdah Joan Zunde JUNE 2006

Contents Foreword

ix

Introduction

1

PART 1 THE PURPOSE OF BUILDINGS Introduction CHAPTER 1: Origins CHAPTER 2: Moderation of the environment CHAPTER 3: Use of available technology CHAPTER 4: The demands of the community Bibliography

5 7 9 19 25 33 43

PART 2 THE DESIGN TEAM Introduction CHAPTER 5: The specialists and how they work together CHAPTER 6: The client’s role CHAPTER 7: Communication CHAPTER 8: Professional responsibility Bibliography

45

PART 3 THE DESIGN PROCESS Introduction CHAPTER 9: Creative problem-solving CHAPTER 10: The problem CHAPTER 11: The process in action CHAPTER 12: Aesthetics CHAPTER 13: Evaluation CHAPTER 14: Completion Bibliography

83

47 49 59 63 75 81

85 87 93 107 119 137 143 147

VIII

CONTENTS

PART 4 SPACE Introduction CHAPTER 15: Tailored versus loose-fit outcomes CHAPTER 16: Functional requirements CHAPTER 17: Anthropometrics and ergonomics CHAPTER 18: Relationships between spaces Bibliography

149

PART 5 ENVIRONMENTAL DESIGN Introduction CHAPTER 19: Principles of environmental design CHAPTER 20: Design strategies CHAPTER 21: Case studies Bibliography

193

PART 6 STRUCTURAL CONSIDERATIONS Introduction CHAPTER 22: Structural materials CHAPTER 23: Structures for domestic buildings CHAPTER 24: Design of structural elements Bibliography

251

Glossary Index

151 153 161 169 179 191

195 197 215 239 249

253 255 267 281 289 291 297

Foreword As the President of CIAT I am delighted that the Chartered Institute of Architectural Technologists is supporting this publication which is the first in a series of publications for those who specialise in architectural technology or wish to expand their horizons into this exciting discipline within the built environment. At this time of continued growth within the built environment together with the exciting and innovative flag ship projects around the UKand internationally, there is a great demand for qualified professionals and in particular qualified architectural technology professionals such as the Chartered Architectural Technologist (MCIAT) and Architectural Technician (TCIAT). o Wrking with the publishers, the writers and Advisory Board, CIAT considers that this book will become an essential read for students on architectural technology degree programmes and associated courses.

Jim Kirwan, PCIAT President CIAT MAY 2006

president@ ciat.org.uk www.ciat.org.uk

Introduction B u i l d i n g , a rc h i t e c t u re a n d t e c h n o l o g y The categories of building, architecture and technology often, and in many ways, overlap. They can properly be distinguished. A sensible distinction is to understand architecture as a philosophical consideration of the impact of buildings on peoples’ consciousness, while technology is concerned with the application of scientific methods to their realisation. Building has more to do with the practicalities of creating the actual structures. The professions cannot exist in isolation, and Building Manager, Technologist and Architect as well as all the other professions concerned with the built environment, need a grounding in each other’s concerns as well as empathy with one another’s points of view. Buildings are among the most substantial indicators we have of cultures other than our own. This is true whether we are considering varying geographical and climatic situations or taking an historical perspective. When we visit distant countries or archaeological sites, our understanding of the values and aspirations of the people who made them is vividly enhanced by our experience of the buildings we find there. They speak of the patterns of life that they were built to accommodate, of the conditions under which they were created, and also of the skills deployed by their designers and builders. The buildings created today are similarly evocative. Whilst they serve varied and complementary practical purposes, which are discussed in some detail in Part 1 of this book, they are also markers for our sense of cultural identity. Whether we use a particular building or not, it may be a backdrop to our lives and a significant component of the environment

2

INTRODUCTION

in which we operate. It is an influential factor, whether consciously or not, in our sense of cultural identity. We should also be aware of the statement our buildings make to onlookers about our aspirations and values. Buildings are not only the concern of those who commission and pay for them, nor of those who use them as places of work or as users of services. They are important to us all. A great hospital holds a different place in the consciousness of the Trust who owns it, the medical and administrative staff who run it, the patients who use it and of the passers-by to whom it is just part of the urban scene. The same is true of the most elaborate governmental complex or of the simplest home or bus shelter. Each of these buildings contributes to a total environment. The village or the city is a whole formed from the constituent parts. The coherence of the experience of people within depends not only on the excellence of those individual components in themselves, seen from the point of view of owners, users or of onlookers, but on the total ambience they create. We are all, in this sense, consumers of the whole built environment. It is the profession and art of architecture to empathise with these apprehensions of the significance of buildings, alongside ensuring that the buildings created are beautiful and practical. Buildings which are starkly functional without relationship to their age and their place cannot be described as architecture. Equally, edifices which simply crystallise an understanding of a culture, which stand only as features in a townscape or are merely sculptural, are follies, though possibly enjoyably decorative ones. Works of architecture serve practical purposes and do so well. They must suit the purposes of their users, must use resources wisely and must contribute positively to the visual environment. These considerations are the concern of architectural philosophy. The technologies of architecture, as dealt with in this series, are the developed professional skills and techniques by which the needs of the consumers of buildings in all these senses can most efficiently be met through the use of available resources. They are in every case built upon an ability to assess need, including an appreciation of what is reasonable in terms of economic, energy and time constraints. They never assume that the most modern or high-tech solution is automatically to be preferred, but always regard the low-tech and traditional as parts of the available armoury. Such technologies include aesthetics as well as acoustics, ergonomics as well as engineering, and understanding both of communication and of construction. They are, therefore, sophisticated tools which are necessary to the proper use of resources to provide an appropriate environment for the activities of society.

INTRODUCTION

The expected audience Understanding of such technologies is, of course, an essential component of the professional equipment of architects, surveyors and other practitioners, including structural, mechanical and electrical engineers as well as members of the newly emerged profession of architectural technology. Members of all these professions need to be clearly aware of their interdependence, and need to work in an atmosphere of mutual respect. In some cases, one or another specialist will lead the team involved in developing a design, whilst on other occasions he or she will be a contributing member of that team. In yet other instances, a single professional may be involved. In order to fulfil any of these roles, the practitioner needs a clear view of:

• • • • •

the purpose of buildings; the technology available to fulfil those requirements; the specialisms that contribute to a satisfactory outcome; how teams work; and the constraints upon the design process.

It is expected that this suite of books will be appropriate to an audience which includes students of architecture, and they may be considered essential tools also for students of architectural technology, of surveying and of estate management and construction management in the UK, the Commonwealth and the USA.

Purpose This introductory book, Integrated Strategies in Architecture, provides a preliminary examination of the knowledge, understanding and skills which the professional designer has to acquire. This text stands alone, and is written for a student without prior technical knowledge. The theoretical topics covered are fundamental and basic, and are introduced by way of material with which he or she may be expected to be familiar. It has been assumed that:

• • • •

students already have a suitable equipment of the English language, mathematics and study skills, either at entry or through equalising courses; Construction Technology and Surveying are studied in common with students of cognate disciplines or, at any rate, separately from this syllabus and do not need to be covered here; it is appropriate for the introductory text to cover those topics specific to the professions which it can be expected will be dealt with in the early years of the degree course; and specialised and advanced subjects are covered in the supplementary texts.

3

4

INTRODUCTION

T h e p ro g ra m m e These specialised texts, Volumes 2–5 are, to some degree, time and culture specific, and will be regularly reviewed so that they can be revised as necessary. They are: Volume 2

Environment, Technology and Sustainability Stephen Sharples, Hocine Bougdah and Peter F. Smith

Volume 3

Materials, Specification and Detailing Norman Wienand

Volume 4

Practice, Management and Responsibility

Volume 5

History, Performance and Conservation

The whole suite of books is conceived as a set of course texts rather than as reference materials, since the breadth of data that would be necessary for such books is beyond the scope of student manuals. It will be found that each section of each book is preceded by a brief summary of its contents and followed by a useful list of references. These references are those that the authors believe will be the most valuable to students, but their inclusion cannot preclude the need for individual library research. In the case of websites, the links to these have been confirmed as the texts were submitted, but it is important to be aware that websites and their addresses change frequently.

Part 1 The purpose of buildings INTRODUCTION, 7 Chapter 1

ORIGINS, 9 Houses, 9 The settlement, 10 Ritual sites, 11 Workplaces, 11 Communications between settlements, 12 Commerce and industry, 12 Urban design, 12 Defining space, 13 Unnecessary space, 13 Implicit limits, 14 Privacy, 15 Protection, 16

Chapter 2

MODERATION OF THE ENVIRONMENT, 19 Water, 19 Temperature, 21 Air flow, 22 Sound, 22 Natural disaster, 24

Chapter 3

USE OF AVAILABLE TECHNOLOGY, 25 Natural conditions, 26 Local materials, 27 Traditional technology, 28 Available skills, 30 Examples, 30 Conclusion, 32

6

THE PURPOSE OF BUILDINGS

Chapter 4

THE DEMANDS OF THE COMMUNITY, 33 City and state, 33 Sustainable architecture, 36 Law, 38 Culture, 39 Risk assessment, 40 Tradition, 41 Conclusion, 42 BIBLIOGRAPHY, 43

Part 1

Introduction

Before attempting to understand the mechanisms and techniques which are applied to the design of buildings, it is a prerequisite that the purposes for which buildings are created should be properly understood. These are not merely utilitarian, and are perceived differently by different parties. As technology has gained greater sophistication, so people have set higher targets in every area. In Chapter 1 there is a brief survey of the development of buildings from primitive structures to the present. The important role of the building envelope in modifying the external environment to produce acceptable internal conditions is discussed in Chapter 2. Chapter 3 considers the means available to achieve such aims at different periods and today, and there is an overview of the materials and skills traditionally available to provide suitable structures, with a note of their relationship to climate and skill. Finally, the cultural and legal requirements of the community are discussed, together with a note on sustainability and on risk assessment in Chapter 4.

Chapter 1

Origins

The most important part of a building is the space it defines. The other parts exist to define that space and to modify the environment experienced within it.

Houses The earliest buildings created in all cultures are dwellings, not so dissimilar from the lairs or nests created by other animals, and intended to serve somewhat similar purposes. These are initially threefold:

• • •

shelter, in terms of moderation of the climate; protection from predators; and privacy.

The shelter was made in the simplest possible way by the people who would occupy it, and the size of the home that could be created was severely limited by the materials available in the immediate vicinity and by the strength and skills of the people. It might well serve only on a seasonal basis, either because of its innate perishability or because the occupants were nomadic. These considerations apply to homes in climates as varied as the plains of Africa and the North American tundra. Homes everywhere would be of somewhat similar size – just large enough to accommodate a sleeping nuclear family – and they were almost always circular because that is the easiest shape to build and has the most economical relation between perimeter and area. The significant variations between the houses arise from two important factors:

1.1

10


• •

the climate from which shelter was required, which might include almost any combination of cold, wind, rain, snow or fog, or of heat, glare and sand storm; and the materials available – stone, wood, skins, grasses, ice blocks and so on.

So that the yurt, igloo, hut or tent were created from the most readily available materials to meet specific environmental conditions. From these very earliest beginnings, such considerations were intimately connected, and could not be considered in isolation. Whereas most animals continue generation after generation to create similar shelters, humankind is adventurous, creative and ambitious. Once the notion of making them rectangular was appreciated, houses could become larger, and they were expandable. More than one cell could be created under a single roof. Even later, when the beam was invented, they could be broadened as well. As skills developed, so did expectations, and homes have continued to become more sophisticated and so create even greater aspirations among potential owners. A fourth purpose can, as a result, be added to the three mentioned above: statement. That is to say, from quite early times it came to be the case that dwellings told onlookers something about the people who lived in them. If they could afford to employ skilled specialists on the building, or to bring expensive materials from far away, this added to the occupants’ prestige. In its simplest form, this can be seen in the Chief’s home being larger and more substantial than those of others because he could command the resources of materials and labour as a result of his position.

The settlement The small clusters of dwellings constructed by an extended family evolved into permanent settlements, as a hunter-gatherer society developed into a settled agricultural one. Such villages were carefully sited where a good supply of clean water was available, as well as suitable land. From a very early stage, care was taken to draw water from a higher point in its flow than the position where wastes were discharged into it.

1.2

Although there was no land hunger, the dwellings were built close to one another, largely for defensive reasons. In some regions they were sited contiguously, so that access was across roofs and downwards into individual dwellings.

ORIGINS

Ritual sites The second category of sites which appear to have been set apart for specific purposes consists of those that archaeologists loosely classify as ‘ritual sites’. Such constructions were of course fixed, and even in a nomadic society would be objectives of pilgrimage. In these cases that fourth purpose, the statement of function, seems to have been paramount to those who made the spaces. Often, however, there is still doubt about the precise purpose. These might be spaces cleared and surrounded by defining structures, such as ditches or banks, or henges marked by stone or wood circles; in which case it seems most likely that they served for community meetings or for worship or the casting of oracles. It is reasonable to define them as monuments. The circle was still the preferred plan form. Focal sites were generally chosen, and the monuments are often found on skylines or across valleys, where they can be readily seen from settlements even when these are at some distance from them. A subsection of this category is the cemetery. The disposal of the dead seems always to have been treated with reverence by the great majority of cultures, and tombs and burial places were generally carefully designated. All such spaces that are successful share a characteristic which is known as ‘the numinous’ – they catch people’s imagination in a way that is interpreted as sacred, and generally without resort to the use of symbols. This can be considered to be a special category of the importance of ’statement’ in design.

Wo r k p l a c e s Thirdly, while in the most primitive cultures the open air or the home sufficed to accommodate the necessary chores of living, the need for defined workplaces came with the specialisation of skills. Such accommodation might be in the form of special, additional parts of the dwelling set aside for weaving or cooking, or of specially constructed shelters with hearths for smelting or other specialised facilities. Initially such buildings were, inherently, solely functional, but they came to be regarded as prestigious gauges of the prosperity of settlements, and treated with suitable respect. The smith and the potter were people of position and power because of their seemingly almost magical skills, and their workplaces were treated with due dignity.

11

12


Communications between settlements The position of settlements near to water courses meant that there were straightforward channels of communication between them, either along the rivers or through their valleys. Once these were established, trade between settlements became possible, and specialisation developed rapidly, encouraging skills to be further honed and promoting the exploitation of locally occurring materials.

C o m m e rc e a n d i n d u s t r y Eventually, commercial networks emerged, so that artefacts of far distant origin are found in the excavations of very ancient sites. The expansion of regional industries led to high degrees of the concentration of trade, and therefore to sophisticated business networks, initially based on barter but soon demanding the introduction of currency.

Urban design The development of these three strands of buildings – domestic, ritual, and public and commercial – lies at the heart of the understanding of urban design.

1.3

The city is sometimes believed to have developed as a marketing centre for a hinterland providing agricultural produce, perhaps to a military presence. Another theory is that cities grew up where there was a centre of industrial manufacture, requiring marketing outlets. In yet other cases, it is believed to have come into being solely for the commercial exploitation of a rare and valuable resource (such as obsidian in Turkey). What is certain is that the concentration of population housed in even the earliest cities:

• • •

1.4

required to be fed from outside the city walls; had to have their urban environment carefully planned if they were to work efficiently; and needed to be efficiently defended, and therefore the very highest practicable density of development was required, so that the perimeter defences were minimised.

Providing the necessary built environment became a specialised occupation, in which it continued to be essential to give appropriate weight to the considerations of spatial needs, of the available technology in terms of materials and skills, and of the climatic conditions, as well as to the architectural statement.

ORIGINS

It is essential today, as it was in earlier periods, that such matters are never considered in isolation, but that the application of the sophisticated technologies now available is integrated into a holistic approach to the design of buildings.

Defining space Part 4 of this book deals with the design aspects of the arrangement of physical spaces within buildings. Other aspects of the topic must not, however, be overlooked. As has been noted, humanity has the characteristic of competitiveness. The outcome was, and is, that people aspire to what others have – and the ‘chief’ sees a need to stay ahead. ‘Keeping up with the Joneses’ has been a powerful force in driving the evolution of buildings, and perhaps especially of homes.

Unnecessary space One result is that the very small amount of space that is actually required to house a family is no longer considered sufficient. One has only to consider the size of a tent in which explorers can be accommodated, or the carefully planned holiday caravan, to appreciate this. Of course, it is also true that the furniture and (particularly leisure) activities that a home is expected to contain have multiplied through the generations. However, people have also become more conscious of the need for privacy, not only between families but within them. There are physical reasons, concerned with the size of the body, of the equipment and furniture used and what they are made of, which govern minimum spaces, as considered in Part 4, but additional space is often expected, for a variety of reasons:

•

Personal space. People feel invaded if they are required to spend time in too close proximity with others. It has recently appeared that many passengers travelling alone on long distance coaches are happy to pay for two seats, to avoid having to sit with a stranger. They need a capsule of space that they feel they can call their own. This is because each person likes to think that they control the invisible space directly around them, while the size of this personal space varies with circumstances, and with the company among which they find themselves. Among strangers it is much larger than with friends, and can extend up to a metre forwards and half a metre to the sides and behind. For everyone, and in all circumstances, it seems that invasion of that space causes psychological discomfort, and therefore in a working situation leads to inefficiency. For this reason it is necessary to

13

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•

•

take this, often subconscious, need into account when working out the sizes of accommodation to be provided. Prestige. Subtle signals are needed within organisations to clarify hierarchical relationships, and space is often employed. The boss’s office is usually bigger than her assistant’s, even though the assistant may have more paperwork to accommodate. Extensive foyers and long vistas serve to impress visitors with the importance of an establishment, and to tune their mindset to what is perceived to be a suitable deference. The provision of redundant space is a palpable extravagance, and so informs the observer that the enterprise is powerful because it is rich. Authority. In other cases, the need to impress results from the imperative of asserting authority. Spaces such as courtrooms, churches and audience chambers are, in addition to being spacious, often much higher than either acoustics or ventilation would require, which serves to convey an impression of authority. This is generally associated with the over-scaling of other features, such as door heights.

An awareness of all these requirements, which may be classified as wants rather than needs, and may well not be expressed, will augment the designer’s assessment of stated functional necessity.

Implicit limits Although most spaces will be entirely enclosed by structures, and will be internal, it is perfectly possible to identify areas set aside for specific purposes by other means. These might include the following.

Internally

• • • •

Transparent screens of glass, trellis or indoor planting. Changes of floor level, a sunken area often being apparently more intimate, while a raised one invites public scrutiny. Changes of ceiling level have similar effects, and are less hazardous. They also often affect levels of lighting. Changes of lighting, finishes or simply colour range can identify spaces set aside for specific purposes, and may help to make very large open areas coherent.

Externally

• •

The placing of the building in relation to others in the urban scene, creating places, vistas or street facades. The relationship to internal accommodation, as in the case of a dining terrace near to a restaurant.

ORIGINS

• •

Changes in paving schemes. Physical divisions created by planting or semi-enclosing banks (which may be quite low) or ditches.

It will be seen that the perception of space is not a function only of three-dimensional containment, but of subtle changes in the ambience. Providing useful space is not, therefore, merely a simple process of deciding on the structure of walls and roofs, but of deploying an armoury of techniques to convey the required message to the owner, the occupant, and the visitor and the passer-by.

Privacy Privacy between dwellings The intimacy of a family unit is closely connected to the sense of identity of the members, and needs to be protected. A major factor in preserving the relationships within the unit is its separation from neighbouring groups. The extent to which this is considered necessary varies between cultures. In some, the tribe or the extended family is the dominant unit, but in modern western society it is almost universally the nuclear family that is focal. For this group to feel a full sense of security in which it is possible to relax, privacy from neighbours is required. This means screening from being heard and seen by, and needing to hear or see, the members of other groups. The layout of housing schemes is hugely influenced by the understanding of this, including such considerations as:

• • • •

the situation in which it is possible to look straight through a living room from window to window is invasive and best avoided; windows of different dwellings should not overlook one another, requiring the installation of blinds; living spaces of adjacent dwellings should not be planned immediately adjacent through party walls unless adequate sound insulation is provided; and appropriate action needs to be taken to minimise sound penetration between floors of blocks of flats.

One point for debate may be the desirability of fencing the front gardens of dwellings. The open effect of the unfenced residential close is attractive, but if it is adopted it is essential that either living areas do not overlook the street (so that they are not subject to peering neighbours) or that some means is found to limit pedestrian access to the immediate vicinity of buildings.

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16


Privacy within the dwelling The fact that individuals within a family need their own refuges is often overlooked. It is certainly a requirement that has only grown up with the proliferation of technologies and activities available to recent generations. Some sociologists might see this as a trend that should be reversed. However, social engineering does not fall within the remit of the designer, whose aim should be to provide the requirements as they are perceived by the household. It is therefore necessary to consider the competing use of different styles of music with the need to study quietly, for example. Dwellings have become increasingly open planned, and this trend has to be balanced against the desire for seclusion. Visual privacy may be easier to provide, especially where moveable structures can be utilised.

Privacy in the workplace In offices and workshops there can be a conflict between the need for supervision and the privacy which encourages the most efficient work. Possibly the most important point to be remembered is that supervision should not be covert – staff accept proper management and the reassurance that they will be supported, but are made uneasy by perceived spying. Business and commercial premises, however, frequently have to guard valuable secret information, and the means needed to keep this secure generally take priority over the free movement of personnel.

P ro t e c t i o n The primitive requirement for protection was principally defence against hostile marauders or from animal predators. People protected individual dwellings by building them with a single, defensible access point, and often by building a fire immediately outside the opening. Settlements were defended by surrounding them with ditches and ramparts, and again by limiting access. In our very different society we can still identify a number of enemies against which (or whom) defence is needed. While the installation of smoke and gas detectors, or intruder alarms and safety locks, is well advised and reduces insurance premiums, the psychological component of defence also needs to be considered. We are inundated with well-meant advice from many sources, and this can produce a false sense of euphoria. The most effective defence is

ORIGINS

always to be aware of potential danger. Protection is needed especially against the following.

• • • • •

•

•

Fire. Occupants should be encouraged to discover the most viable escape routes and appliances available. They usually need to be instructed to put personal safety before rescuing artefacts. Smoke. Smoke and other detectors are valueless unless regularly tested. Electric shock. No one should use electrical appliances unless they are aware of the risks, and never near water. Where there are children or other vulnerable people, sockets should be kept shielded. Flood. Where properties are vulnerable to even very rare flooding, a prepared course of defensive action should be developed and known to all occupants. Predators. Even in the modern age, buildings are vulnerable to the incursions of un-housetrained animals. Sometimes these can be avoided with thought. Cats, other than the householders’ own, can use cat flaps, birds and squirrels may invade roof space, and mice and other vermin are crafty. It is good housekeeping to be alert to invasions and take rapid action. Fungal and insect attack are dealt with in Volume 5, History, Performance and Conservation. Enemies. Terrorist attack is always possible, but statistically extremely rare. Many commentators suggest that, in aggregate, the fear of attack is more damaging than attacks themselves. Occupants even of vulnerable buildings should know the action to take in case of attack but – though aware – should not be obsessed by the possibility. Theft and burglary. The best defence is generally taken to be discretion in the display of valuable and portable property. What thieves do not know of, they will not plan to steal.

In no case can buildings be constructed so as to be invulnerable, though every possible precaution is taken. It is vital that the owners and occupants of buildings are fully briefed, not only of the safety features of buildings but also of the emergency action that may be necessary, and designers have a duty (in association with the relevant bodies, such as the police, fire service and insurance companies) to provide that briefing. The relevant information should be included in the owner’s manual, described in Part 3, Chapter 14.

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Chapter 2

Moderation of the environment In order to focus the discussion away from the wide ranging aspects related to the function of buildings, it would be convenient to narrow it down to the role of the building envelope. Just to illustrate how wide the topic could be, we only have to consider the following statement: Our concept of what a building is, therefore, is more than what would be found in a dictionary definition of shelter. A building is, functionally, what we expect it to be. (Allen, 1980) This chapter will attempt to focus the discussion on certain physical aspects of the building envelope’s role in moderating the external environment in which the building exists in order to create an internal environment that provides comfort and promotes healthy and safe conditions for human activities.

Wa t e r Water is an essential element for life. Human settlements would only exist where there is water. And yet water, when its presence is not under control, can cause havoc and devastation. One only has to look at floods and what they leave in their trail. On a smaller scale, the building envelope should be designed to exclude unwanted water from the interior of the building. Keeping water out would depend on where the water comes from (atmosphere, ground) or in what form it is (free running water, water vapour).

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Precipitation The presence of uncontrolled water inside a building would adversely affect the thermal performance of the building fabric and its durability. It can also lead to the staining of internal finishes and mould growth. Water is present around the building in various forms, such as rain and snow. The presence of openings in the building fabric would allow water to pass through them. These openings are sometimes by design, as in the case of expansion joints, and other times due to bad workmanship. In the case of roofs, when the pitch of the roof is less that 15o, its ability to shed water is slow and, consequently, the risk of water penetration is high. Such roofs, which are usually covered with an impervious membrane, can be prone to leaks. The presence of cracks due to thermal movements would lead to water penetrating the roof deck. Pitched roofs can have their own problems with water penetration. The use of a water-impervious membrane under the roof coverings can help in dealing with the problem. Areas of interface between building components (window/wall) are other areas where water penetration can be a problem, and a detail design needs to take that into effect.

Groundwater Preventing groundwater from reaching the inside of the building can be achieved by the use of waterproof membranes below the ground floor. This solution is mainly used with solid ground floors which are in contact with the ground. Where lightweight timber floors are used, waterproofing the foundation walls is combined with the use of natural ventilation in the floor cavity.

Humidity The presence of humidity in the air inside buildings can lead to condensation either on the internal surfaces or inside the building fabric (interstitial condensation). Both types of condensation are detrimental to the materials/finishes and to human health. The incidence of condensation is an even bigger problem in modern buildings due to the constant increase in the level of thermal insulation combined with increased standards in air tightness. The level of water vapour inside a building needs to be kept under control in order to avoid condensation. This can be done by means of ventilation, background heating and extraction of water vapour where it is generated (kitchen/bathroom). This topic is analysed further in Chapter 19.

M O D E R AT I O N O F T H E E N V I R O N M E N T

Te m p e ra t u re Temperature plays an important role in human thermal comfort. In cool air the human body loses heat too quickly and feels cold. In hot conditions, the heat loss is too slow. The comfort zone is somewhere in between. The conditions inside the space enclosed by the building envelope tend to be moderated compared to those outside, even before any extra heating or cooling is provided. In moderate climates, the provision of comfortable temperatures inside the building can be achieved by virtue of the building envelope. In colder or hotter climates, however, the design of the building fabric is more challenging to achieve comfort conditions with the minimum injection of heating or cooling.

Heating In cold climates, the use of heating is greater, in order to achieve comfortable thermal conditions. The need for heating depends on how good the building envelope is in retaining heat. In warmer climates, the situation could be reversed as the heat from solar radiation outside needs to be stored and dissipated before it affects the inside of the building during the hot day. This is achieved by the use of thermal mass. This is the ability of heavy materials to absorb and store heat during the day and release it at night when it can be ventilated out into the cool outside air.

Insulation For the building envelope to be an effective moderator of cold conditions outside, it needs to have high levels of thermal insulation. Old buildings tend to have lower levels of insulation which make them big consumers of energy in order to generate the heat required to keep them thermally comfortable. The standards in thermal insulation have been steadily increasing since the energy crisis of the early seventies. The increase in environmental awareness has led to an increase in insulation standards. The level of insulation capability of a building element, such as a wall or a roof, is given by its U-value. The lower the U-value, the better. A U-value calculation is among the tasks that a designer or a technologist is required to undertake. In order to undertake such calculations there is a need to obtain basic thermal properties of the materials that make the elements for which the U-value is required. Such data are available from design tables. Further details on how these calculations can be performed will be given in Chapter 19. Different countries around the world have their own national standards for thermal insulation. In the UK, the Building Regulations’ requirements for thermal insulation are a good guide, but should be taken as

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the minimum rather than the optimum. Lower U-values, such as those used in the Scandinavian countries, can pay for themselves in energy savings.

Air flow The provision of shelter from the wind has always been one of the primary roles of a building. This goes as far back as the early human caves that provided shelter from cold winds in European climates and from hot winds in the African and Australian deserts. A building erected in the path of the wind will change the pattern of the local air flow around it. A good design is one that makes use of the natural force of the wind without presenting too much resistance that may cause the building fabric to be damaged. Designers have always attempted to locate buildings on site in such a way as to optimise the effect of the wind. The following two examples demonstrate this point. In the west of Ireland, where exposure to Atlantic cold, strong winds is high, the houses tend to be located on the leeward side of rocky outcrops. Planting trees on top of the outcrop would improve the situation, by providing extra shelter that does not promote turbulence, which solid barriers such as walls do. In warm climates, the exposure to wind is encouraged for its cooling effect. You only have to look at the positioning of houses in mountainous regions of southern Italy and Spain to appreciate their point. Wind, like all natural physical phenomena, is useful, but only in the right amount. Too much wind, either in speed or duration, and physical damage would occur to buildings and their surrounding environment. Too little of it, particularly in warm weather, and the air is still and the need for cooling is even greater. The air movement around a building affects the pattern of air flow inside it. This is important in naturally ventilated buildings. The design of the building should take this into account. Window sizes and their positions in the outside wall, as well as the depth of the room and its height, are all factors that need to be considered. A successful design would take these into account and would make good use of the wind in order to provide shelter from strong winds and to promote natural ventilation from fresh air and to cool the warm inside if needed. Further discussion of natural ventilation and how the site characteristics, including wind, can affect the design are presented in Chapters 19 and 20.

Sound The need for protection from noise would have been less of an issue for early ancestors as most of the noise around us is generated by human activities rather than natural phenomena.

M O D E R AT I O N O F T H E E N V I R O N M E N T

Modern societies are exposed to high levels of noise. The provision of adequate conditions in and around buildings for humans to hear and be heard must be a priority for designers. This can be, at times, difficult to reconcile with other demands such as natural ventilation and views onto the outside. A careful consideration of design constraints and priorities at an early design stage can help solve some of the problem cost-effectively. At this stage, it is worth noting that different requirements related to noise would require different approaches. For instance, dealing with the control of sound between rooms requires a totally different approach to that when the need is to keep the sound in the room and use it to enhance the enjoyment of what is being listened to, such as an opera or a musical.

Insulation To be able to provide the right method of controlling the transfer of noise from room to room, it is important to determine how the noise would travel from where it is generated to where it is likely to cause the nuisance. Two possible ways for it to travel can be identified: through the air (airborne sound) and through the parts of the building that connect two adjacent rooms (structure-borne sound). This latter one can also be known as impact sound, if it is generated on the surface of a structure, such as the sound of footsteps on an upper floor when heard on the lower floor. To control airborne sound, the use of heavy materials, such as masonry, or isolated lightweight structures, such as double stud partitions, is common. To provide noise insulation against structure-borne sound, it is necessary to provide both isolation and damping in the form of a resilient layer.

Acoustic control This method is concerned with the control of sound inside enclosures in order to provide good conditions for the enjoyment of what is being listened to. Such a method is used for rooms for the performing arts, music and speech. The method relies on a knowledge of the sounds being generated and the physical characteristics of the room, such as the floor area, ceiling height, shape, form and materials inside the room. The control of the room’s acoustics is usually left to a specialist acoustician. From the designer’s point of view, an awareness of the issue from an early design stage can help arrive at satisfactory solutions within budgets. The main two principles used to control the behaviour of sound inside an enclosure are sound absorption and sound reflection, which are properties of materials. The right combination of materials for surface finishes inside the room can lead to the desired solution.

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N a t u ra l d i s a s t e r Buildings should provide the right conditions (shelter, comfort, protection etc.) to promote human activities without them being vulnerable to natural disasters. The building envelope is normally designed to withstand natural elements such as wind, rain, snow and so on. With regard to vulnerability to other natural disasters, other aspects of the design come into play. The location of a building should be carefully selected to minimise the effect of flooding. Although the occurrence of floods is rare, their effects can be devastating. The effect of disasters such as earthquakes can be minimised, to a point, by adopting rigorous engineering solutions when designing the structure and foundations. Other large-scale natural disasters, such as a tsunami, are difficult to design for. The solution would be one of managing the urban and rural planning process and using early warning systems that allow evacuation to high grounds.

Chapter 3

Use of available technology Effective design arises from a full consideration of all the influences upon the solution, as they relate to one another. A holistic approach implies that the relationships between the many relevant factors in any particular case will be identified and prioritised, but will not be considered in isolation from one another. The simplest way to understand this is perhaps to examine how traditional forms of building have come into being. In the sophisticated world we inhabit, there are few utopian buildings that cannot be constructed, if the designers call on the whole armoury of materials and engineering available to them, and have a sufficient budget. This has by no means always been the case, and it can be a useful discipline to examine the restrictions which were put on designers of earlier generations by the limits of their technology. They were, in general, constrained to make the most efficient use of a limited spectrum of materials and skills, and there are many instances in which their modern successors will find that such disciplines have fruitful benefits. Among the advantages of working within such traditions will be greater economy, pleasant and unforced conformity with the prevailing character of the built environment in the area, and higher quality because welltried skills are called upon. Although there is certainly a case for innovation where an unusual problem calls for a solution, providing accommodation for straightforward needs will, in a majority of cases, be best achieved by calling on the locally prevalent technology, whether this is that of an advanced Western nation with a strong tradition of engineering skill or that of a developing country dependent on a limited but equally strong craft tradition.

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In many cases, even today, designers will practise within a limited vocabulary of familiar societal and technological means, and will have a natural response to these when operating locally, but it is necessary that they should be aware of a much wider picture and be ready to respond appropriately when called upon to do so. At a simple level, someone who works in the Cotswolds, with its powerful stone building tradition, needs to be equally sensitive to local conditions if called upon to design for the brick-built environment of East Anglia. Even more, the high-tech solutions appropriate to a high-rise commercial building in London will be unsuitable to the provision of emergency housing after a natural disaster in the third world. The designs of buildings and their modes of construction exist in the context of a developed culture, and that culture has to be thoroughly understood by designers. It is often easier to understand this relationship by reference to historical models or exotic environments. It is, therefore, helpful for designers to understand the technologies which have developed in response to the local conditions in a wide variety of societies, as this can lead to a discernment of the influences behind one’s own local tradition in the present day world. It is possible to distinguish three aspects of ‘available technology’ which form the context of design and which can be examined separately. These are the site, local materials and the technology developed in response to these.

N a t u ra l c o n d i t i o n s Using the site The buildings with which the construction industry is concerned are set in natural landscapes or townscapes – even if they are part of high-rise developments or are earth sheltered. Every building, inescapably, has a relationship to its site, and the examination of traditional models will show that success has often been achieved by exploiting the natural conditions. Thus, sites are chosen for their orientation, for the shelter afforded by the contours, or for the defensive advantages of farranging visibility and raised situations. Natural slopes are exploited to provide efficient drainage or distant views, while the ease of communication and water supply afforded by river valleys leads to the siting of towns and smaller settlements. The ground conditions, too, have a pervading influence on the kinds of building which become endemic. Where there is a solid rock foundation, very different styles naturally develop from that which may be usual where poor ground demands that loads are spread.

USE OF AVAILABLE TECHNOLOGY

Responding to the climate Traditional forms of building world-wide have developed in response to the local environmental conditions, since an important purpose of providing buildings is to modify the external conditions so as to provide acceptable internal ones. It is possible to see important principles in action, when the practices of, for example, the builders of the Far East in their orientation and screening of dwellings to maximise air flow while minimising direct sunlight are observed. Similarly, the means adopted by the people of regions with heavy precipitation to drain the water rapidly, and to prevent its entry into buildings, can be an informative study. The courtyard houses common around the Mediterranean offer privacy in settlements developed to high densities because the distribution of services needs to be compact. Such responses lead to strong local character in buildings, entirely appropriate in situ but which seem exotic and inappropriate when aped under different conditions.

Local materials Natural materials Whatever such climatic imperatives may be, humankind has generally had to develop ways of coping with them while being able to use only the materials which occurred locally. In a world where transport is easily come by, it can be difficult to appreciate that at one time a family building a house had little choice but to use the stone found within a few miles, or the bricks made from local clay. In other areas, only timber was available, while in some others skins provided the most useful means of shelter, and so on. In every case, a clear local tradition of building developed, as the characteristics of those materials were properly understood, so that they could be fully exploited. It was, perhaps instinctively, well understood that masonry could withstand only compressive stresses, even if these were not named, and the workable relationship between the height and thickness of structures became known. The ability of timber to perform well in bending, because it could take tensile stress, was also grasped. In the British Isles, because craftspeople came to understand such materials intimately, a degree of specialisation encouraged the development of highly sophisticated ways of using them. Brickwork was twisted into Tudor chimneys, stone was shaped and carved to emphasise its structural forms, and the timbers of hammer beam roofs, as well as being fixed with elaborate and effective joints, were enhanced with carving. Similar evolution can also be observed elsewhere, in the

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Moorish dome or the Japanese house, based on a post and beam structure organised on modular lines.

Manufactured materials In developed countries, the advantages of factory fabrication of building components have long been understood. Production under controlled conditions, in a covered environment and to rigorous quality standards, has become a norm for all those building elements, such as windows or flooring, that are repetitive and in widespread use. It is also economic to produce many one-off items on the factory floor, since roof trusses, for example, may be specially created for a specific building but will share characteristics with those for use elsewhere. Because of this, buildings become, to an extent, homogenised and local decorative tricks are sometimes used to enhance them. When this is done without reference to the underlying construction the effect is superficial, and the urge to add ‘local character’ in this way is probably, in most cases, best resisted.

Tra d i t i o n a l t e c h n o l o g y The common pool As discussed above, in any community there exists a pool, usually called the ‘vernacular’, of practised methods which are known to be effective in harnessing locally available materials to address locally experienced conditions. Such practices may be found to have depth but little breadth. At a primitive level, they are usually felt by the indigenous population to be ‘the only proper way to build’ and they must certainly never be discounted – but they lack breadth and their applicability beyond the immediate sphere is limited. Much of this is not only true of deeply traditional styles (pargeting in Essex, raft foundations in the Fens, dry stone walling in the Dales) but has a wider application. Study of the construction of houses variously considered ‘traditional’ in England, Scandinavia and North America reveals surprising differences, which can be traced to the varying climatic conditions and the available physical resources.

The beam, the lintel and the truss

3.1

In Britain, the use of posts and beams rapidly developed beyond the simple placing of a freestanding beam over supports, through the introduction of girders to the development of well-considered joints, so that a frame was created. This frame was found to have enhanced strength if it was three dimensional, as in the case of a framed roof or a half-timbered house.


Such a house is a telling example: the frame is created from members of smaller cross-sectional area than might be expected to be required because the members act together to resist the loads. The small interstices can be filled by a variety of materials, depending on local supply, and creative ingenuity is devoted to providing decorative change which enhances rather than distracts from the structural statement.

The arch, the dome and the vault The invention of the arch was arguably the most important single step in the evolution of construction technology. Those cultures where the arch was unknown, such as the Inca, could cover only those spaces which their stone or unframed timber beams could span, so that their buildings were crowded with columns and dark. The discovery that a series of small wedge-shaped stones could become self-supporting immediately freed-up planning, allowing for a series of rectangular spaces to be opened up to one another. Study of the development of the vault, from the simple lengthened arch of the Roman barrel vault to the intricate balance of a Gothic cathedral, can be revealing. A further technological step is seen to be the invention of the pointed arch, which allows the vault over a rectangular space to have level ridges in both directions. What seems to have happened is that the barrel vault was developed into a cross vault in order to provide better wall surfaces for windows, and better headroom. When two half-circular vaults intersect, the diagonal arches across the space are of a depressed circular shape, and could not be simply constructed, so the two vaults have to be centred and built separately. When builders began to limit the amount of centering they required by building semicircular arches across the diagonals as a first step, they discovered that pointed arches over the vaults were a convenient solution. Arising from that, it became clear that the two vaults did not have to have the same span, provided the pointed arches reached the same height; and, to great advantage, level ridges could be constructed, so that minimal support was needed during building. From this, the elaboration of the Gothic vault developed. The pointed arch is not a decorative trick, it is an elegant engineering device. Similarly, consideration of the way in which domes have been used, from the earliest corbelled ceiling of a beehive tomb to the elegance of Sancta Sophia in Istanbul (see Figure 12.3 on page 123), enhances one’s understanding of, and respect for, the work of past technologists. These three considerations, therefore, provide the context for effective design.

3.2

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Av a i l a b l e s k i l l s Training the craftspeople The traditional method of acquiring the necessary skills to build successfully was, for centuries, simply being around and watching the skilled masons or carpenters, bricklayers, thatchers or plasterers while performing supporting tasks, until eventually the skills were learned almost by osmosis. In many cultures this system still applies. In the West, such a system developed through the craft Guilds into a carefully controlled and staged progression to fully skilled status, and from this the apprenticeship system emerged. This is nowadays supported by formal study in college. Formalisation in this way has sometimes been thought to limit the pool of potential craftspeople that was available, since literacy and numeracy are essential to formal study though they are not always necessary for delicate and skilled work with tools. The United Kingdom now educates a large tranche of well-prepared managers for the industry, but has struggled to provide a sufficient supply of craftspeople to maintain traditional skills. Those people with the skills can, rightly, command a high price. It will be agreed that the best design can only be implemented if the necessary practical skills are available – and it is evident that design decisions sometimes have to be limited by the skills known to be obtainable within the cost limits.

The semi-skilled workforce The growth of factory production, mentioned above, has led to much on-site building work being a matter of the careful assembly of prepared parts. The skilled eye of the craftsperson is still needed alongside the judgement of the manager, but in addition a body of semi-skilled assembly workers may be deployed. It is arguable that these do not need to be trained through the rigorous craft apprentice system. What are not required today in western societies, though still greatly needed in the third world, are the large numbers of unskilled manual workers once necesssary, whose role has largely been superseded by the use of plant.

Examples Readers will be aware, from their own study and experience, of a variety of primitive building types. The examples offered here are mentioned because they are among the less well studied kinds of building that may be encountered.


The trullo Trulli are buildings, put up as single-cell circular constructions of dry stone, heavily rendered and whitewashed, which are grouped to form houses or to stand singly as barns or stores in Puglia in southern Italy. Where several are linked into a dwelling the internal openings lack doors, usually being shielded by curtains. Windows are small and few. The conical roof of each trullo, also of stone, is corbelled and completed by a decorative finial, which is informative of the occupation or other characteristic of the occupants and which will be the only enhancement. They are simply built from the found stones of the countryside. Upper stories are rare, but rafters are frequently inserted at what would be ceiling level, to provide storage racks.

3.3

The local legend is that trulli originate from a need to demolish and rebuild at regular intervals (to avoid tax). If they are intended to be temporary, they share many characteristics of other simple circular buildings, such as tents and igloos. It is noticeable, however, that the plan of linked circles demonstrated by the trulli is similar to the earliest megara of the Aegean, from which the familiar classical temple form is said to have evolved.

Troglodyte buildings In Capadocia in Turkey, as in Ethiopia as well as other places where the rock is comparatively soft, it is possible to see dwellings and other buildings hollowed out of the rock. These are not specifically cave dwellings, which are merely the colonisation of existing spaces, since these homes have been deliberately created for occupation. While attempts are made to equate the accommodation provided to that which would be found in a built house, it can be informative to see where the priorities lie. Generally a generous family living room/kitchen is the main accommodation, with minimal private sleeping spaces. Windows are barely sufficient to provide daylight. Turkey is believed to have between 30 and 40 underground cities. The one at Derinkuyu is extensive, and not fully explored, but is probably on 18 to 20 floors, and could have accommodated around 20,000 people. It was apparently built for defensive reasons. It has not been in use for more than 100 years, but elsewhere around the Mediterranean and in Africa (and until recently in Yorkshire), such dwellings are still in use. The necessary skills of carving out spaces, instead of surrounding them with constructed enclosures, may have been taken to the extreme in the rock cut Treasury and tombs of Petra in Jordan. Similar skills were employed to construct the rock-carved churches at Lalibela in Ethiopia, which are believed to date from the twelfth century. These skills, though

3.4

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concerned with working on rock with tools, are of course quite different from those of traditional masons. The study in depth of the topics mentioned in this chapter is unfortunately beyond the scope of this book, though students should make every attempt to become familiar with such subjects, as an understanding of them will enrich their approach to modern and local techniques. The study of scaffolding, both indigenous and exotic (for example the use of bamboo in the Orient), can also be revealing. There is one caveat. Present generations have the advantage of accurate calculation methods, so that innovation can be safely attempted. Earlier societies had to learn by experience, by trial and error. They undoubtedly wished to cover the greatest possible space with the least expenditure of material and effort, and to produce buildings which modified the internal environment as simply as possible, and the buildings that have remained to us are supremely successful in that regard. We do not, it should be borne in mind, see the many experiments that failed along the way.

Conclusion In a properly integrated approach to design, the geography and geology of the site, the nature of the materials available and the ways in which these can be used, will form a context to the problem and its solution. In modern terms, difficulties with the subsoil or the contours of a site or the climate of a region will appear as challenges to be overcome. The whole spectrum of natural and synthetic materials will be known to be available, and highly developed skills can be called upon. Nonetheless, part of the success of the outcome will always be the judicious use of these resources within sensible economic limits. It will be seen, therefore, that alongside their developing understanding of the most sophisticated design, engineering and construction methods, designers should acquire sound understanding of the way in which these means have evolved, locally and generally, so that their work grows out of that of their forebears rather than constantly attempting to overturn it. Useful material will be found in Volume 5, History, Performance and Conservation, but this should complement an observant attitude and a mind alert to the traditional methods of the area in which the student (or practitioner) lives, and an inquisitive wish to understand the different modes of building encountered elsewhere. It is also essential to be aware that the study of historic models cannot provide answers to modern problems, which need to be analysed in depth and solved within the whole context of modern technology.

Chapter 4

The demands of the community City and state One of the first distinguishing marks of a community is that the members co-operate in establishing guidelines for their activities, so as to balance the rights and responsibilities of individuals with those of the community as a whole. The balance that is arrived at may depend initially on the relative power and wealth of the parties, resulting in the emergence of any one of a variety of political systems. In any of these, whether tyrannical or as democratic as it is possible to devise, personal interests inevitably have to be sublimated to the common good. Among the primary concerns of any state which are likely to have an impact on the buildings permitted, will be the following:

Defence The layout of a settlement has often been determined by defensive considerations – in particular by the need for a surrounding protective structure, or by a convoluted street layout which is easier to defend than to attack. In a modern context, some states have required the construction of fall-out shelters, while others specify water storage to allow for the disruption of mains services. Fire is a principal danger, and the prevention and fighting of fire, with escape from it, lie at the root of much building legislation.

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Health and welfare of the citizens It is usual for the design of mains services to be centrally planned, and for there to be stringent rules controlling the standard of domestic services which may be supplied by them. Similar considerations apply to the design of sewerage. Additionally, the provision of adequate natural ventilation and of daylighting to properties may be controlled by rules about relative heights and spacing. Access for emergency services may also be subject to control.

Safety Building codes generally protect the safety of those constructing buildings as well as those who will use them. It is normal for high margins of safety to be required, to allow for human error, for accident and for occasional overload, so that buildings are generally required to be several times more resistant to external forces than theory alone would indicate to be necessary.

Contracts The state has an interest in maintaining a fair and well-understood framework under which obligations are undertaken, and no written document is generally required for most private purposes. It is important to understand the circumstances under which an enforceable contract exists: generally when an exchange of goods and consideration has been agreed. In the case of buildings, contracts are fulfilled over time, and written forms are therefore usually desirable. The legal system is helpful in codifying commonly used contractual forms. It is at least arguable that such forms generally operate to limit rather than to extend liability.

The use and conservation of resources At different times and in different locations, the resources which were scarce have been different, though with globalisation this is ceasing to be so much the case. However, as transport itself becomes a diminishing resource, this situation may be seen to change, and pressure to use the materials and sources of power nearest to hand is becoming evident. As some once valuable resources (for example flint) cease to be of importance, others previously neglected (such as iron ore) may be found essential. This is well understood in a historical context, but needs to be considered in a modern one as well. The community has an interest in ensuring that every resource is used responsibly.

THE DEMANDS OF THE COMMUNITY

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R e s o u rc e s a n d re s e r v e s The distinction between resources and reserves is important, and failure to understand it leads to considerable confusion. Consideration of the example which follows may help. Over the last half-century there have been regular warnings that fossil fuels were going to run out by a frighteningly close date. This date would pass, and there would still apparently be plenty of oil and gas, but another doomsday would be identified. This scenario could arise because, though the total amount of oil or gas in the global system had not increased, continual exploration had identified new deposits, increasing skill at extraction had made hitherto inaccessible stocks accessible, and/or the increasing price that could be demanded for a diminishing resource made more expensive methods of extraction economic.

Inaccessible

4.1

Accessible

RESOURCE

Extractable

RESERVE

Certain

Likely

Assumed

Undiscovered

It is important in this context to differentiate between renewable and finite resources. In the case of the former, wise management results in a viable and sustainable system. It is with the depletion of the latter that concerns are properly raised. A resource is the total amount of a material, or of a good, which exists, whilst a reserve is the (much smaller) amount of that material or good that has been located and can be economically exploited. We can classify the known existence of a finite material as certain, likely, assumed and undiscovered, and the viability, or ease of extraction, as extractable, accessible and inaccessible. On each of these scales of certainty and viability, the boundaries are continually moving in the direction of greater known availability and wider accessibility. continued overleaf

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It is for this reason that we seem to have weathered a number of expected fail points for fossil fuels without actually running out. The danger is that this experience might lull people into false security. This is perilous, as however much more of such an item we identify that we are able to use, the source is still finite. We still have a duty (and a self-interest) to conserve fossil fuel, by low energy uses and by the exploitation of renewable resources. No resource is infinite in extent, unless it is renewable in the short term, and demand makes a resource more expensive because of the difficulty in finding and exploiting it as well as the intrinsic tendency of business to put as high a price as possible on scarce goods. In any case, though technology makes the greatest efforts to find replacements for diminishing fuels and other essentials, we cannot assume that these will be immediately successful – or have total assurance of eventual success. It is likely that lifestyles will have to be seriously modified before planetary resources become accessible, for example. The forward looking design of the built environment is an essential prerequisite of this evolution. It must, however, be recognised that there is debate about the acceptability of wind generators, for example, which is often based on nimby (not in my backyard) lines, based on prejudice rather than information, but in which people’s strongly held views about their visual environment may be derided. The energy model may be the best known, but it is not only in the field of energy that resources need to be used with caution. Our countryside is a diminishing resource, too. Such a model does not only refer to earth-borne deposits. One could seek to estimate the availability of electricians. The certain reserve would consist of those already trained and qualified, the ‘likely’ would include those in training (some of whom might change their career path), the ‘assumed’ all those soon to leave school who had studied appropriate subjects, and the ‘undiscovered’, those who might immigrate, or give up other careers to retrain. On viability, the easiest to use would be those already at work, the ‘marginal’ would include those near the end of their careers and those not thought very competent, and the (currently) ‘inaccessible’ those who were doing better paid jobs in other spheres. It might be found that it was desirable to use electricians wisely, where their knowledge and skills are really needed (and perhaps pay them better), else we may find ourselves reduced to the self-dependence of primitive societies.

S u s t a i n a b l e a rc h i t e c t u re The Sustainable Building movement is part of a more general attempt to make maximum use of global resources without exploitation of producer populations or extravagantly wasteful use by richer communities. It is a response to the recognition of corporate responsibility for the management of the widest range of resources within the context of a safe and defended community. The generally expressed aim where the built environment is concerned is, as in other contexts, to eliminate pollution and other forms of wastage and to achieve parity of distribution.


Sustainability in this context must not be imagined to equate only with self-sufficiency in energy use. While attention to energy efficiency may be an important, indeed an essential, component of sustainable design, many further social and fiscal considerations are involved. The movement has had a number of manifestations, among which are the following:

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The low-tech model. This pattern assumes that traditional methods will always be preferable, largely based on the reasonable assumption that methods which have developed over centuries in a particular geographical area are likely to be the best adapted to the conditions which will be prevalent. One aspect of this approach is to emphasise the benefits of technologies that have fallen into disuse, but which can be adapted to modern needs, such as the use of adobe or straw bales. This has the very useful function of opening the minds of traditionally trained practitioners to materials and methods they might otherwise overlook, but can result in some cases in the adoption of obsolescent methods for their own sake, in a ‘politically correct’ spirit, and to no demonstrable practical advantage. The global model. In this case, the intention is to exploit the growing ease of inter-continental communications to allow for resources to be shared across and between communities. A main feature of this strategy is that resource-rich communities (such as those with extensive oil reserves) must put international interests ahead of national and commercial ones. Thus, while there may be extensive public will to achieve parity of supply, current structures militate against success. The energy and other costs of distribution have to be factored into the calculation. The explore and exploit model. Here, the intention is to expedite the discovery and exploitation of resources in advance of demand, so that such multiplying demands can be met as they arise. Such an approach demands significant international investment ahead of any assurance of suitable return on capital, and this depends on stability. It also encourages a demand which may become insatiable if the perception that all demands will always be met becomes imprinted. The mixed model. This is exemplified by the work of the Centre for Alternative Technology, where a high standard of technological sophistication, including electrical and electronic domestic and office machines, exists within an environment 100% self-sufficient for energy.

A balance needs to be struck within all such models between the drive to sustain a twenty-first century western lifestyle and the imperative of conserving valuable resources for the twenty-second century. A powerful educational programme is therefore required, so that expectations are suitably modified.

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Whichever model/s, or modifications of them, are adopted, lifestyle and the political system, as well as the natural environment, are important factors in decision making. So is economics, though it seems unlikely that that can continue to occupy the priority hitherto enjoyed. The movement towards self-build has been related to the sustainability movement. There are negative as well as positive aspects to this endeavour. While owner-builders may be expected to go to extreme lengths to achieve the quality they desire, and may be prepared to expend time and effort beyond the economic resources of commercial firms, their limited skills and experience have sometimes been found to restrict both the result they expect and the outcome they can achieve. Sustainability must essentially be considered as a holistic approach to the design of the built environment, and in general demands a new and integrated understanding of the technologies and sociology of buildings for its success. The subject is extensively surveyed in Volume 2, Environment, Technology and Sustainability, as well as in Volume 5, History, Performance and Conservation.

Law The areas mentioned above all have an impact on the kinds of building which governments determine can be permitted. The state has two major means of control:

•

•

Economic and fiscal policy, controlling relative costs, and so making it in the interest of developers and building owners to conform to acceptable practice. Both taxation and exchange rates may be employed. Legislation, imposing sanctions on those who fail to conform. Such sanctions will normally vary with the severity of the harm done, actually or potentially, to the community or members of it.

In the United Kingdom, building legislation is regularly updated in keeping with the latest research and experience in practice, and the most important areas are the following:

•

Planning control. Some areas of control had long existed on what could and should be built in which situations, though this had often been a matter of viability and of agreed consent. After the Second World War, with the need for the rebuilding of bomb-damaged cities, a great interest in their proper design grew up, and with it planning legislation, especially the Town and Country Planning Act 1947, to ensure that long-term plans were made into which individual building proposals should fit. In particular, there was to be regulation of the zoning of areas, to segregate industry, commerce and housing, as well as national and regional determination of the transport infrastructure.


•

Local authorities (LAs) were required to prepare proposals, subject to public scrutiny and the agreement of central government, and no development of any size could be done until it had been carefully evaluated against the criteria established in those plans. The designation of buildings and areas of historical and architectural interest, so that they were properly protected, also became important. Building regulations. Whilst local building edicts had been promulgated for centuries, these had often been sidestepped, and in 1619 a commission was set up to ensure that they were properly enforced. This is considered to be the origin of modern building legislation. This area of control received an important impetus from regulations imposed on the rebuilding of the City of London after the Great Fire in 1666 (the Act for the Rebuilding of the City of London 1667). For many years control continued to be locally based, different LAs devising separate codes of byelaws which were intended to reflect local conditions and concerns. Eventually, a model code was introduced (under the Public Health Act 1936) from which it was still possible for LAs to vary with permission, although building in London continued to be controlled by a succession of London Building Acts. The Building Byelaw system was finally abolished by the introduction of the 1966 Building Regulations in which the national pattern of standards was established. Whilst the byelaws had generally described patterns of construction which must be adhered to, a revision under the 1984 Building Act made it a distinguishing feature of the Regulations that they describe standards to be achieved, and that while acceptable solutions were referred to, it became possible to propose alternatives. This was intended to stimulate innovation with minimum risk, in an environment of rapidly evolving technology. The Building (Amendment) Regulations 2004 made important alterations to meet modern concerns, and it is to be expected that such evolution will continue.

Even law-abiding property owners often find it difficult to accept that the community can properly have any interest or control of what they do within their own building, and care may be needed to avoid a series of appeals against perfectly legal rulings which clash with the owner’s wishes.

C u l t u re There is a surprisingly large number of factors which are, to a greater or lesser extent, culturally determined, and which affect the perceptions of which buildings are acceptable in different contexts. Whilst working within one’s familiar community, these are largely taken for granted, but

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on any occasion outside the familiar parameters (such as designing a building for an overseas site) they need to become explicit. These considerations are mutually influential, and it is therefore necessary for designers to familiarise themselves with a whole package of cultural variation. Matters which might need to be taken into account could include:

• • • • • •

the level of seclusion expected, especially for women; objection to the use of particular materials; the separation of food preparation from ablutions; the availability of craft skills; orientation; and the need to exclude predators.

When the variations of building form required by climatic differences, and of locally occurring materials, are taken into account, it is surprising that twenty-first century building is so standardised across the planet.

Risk assessment The technology of risk analysis and management has become increasingly sophisticated, and applied over many fields, ranging from the personal risk of contracting any one of a number of medical conditions to the forecasting of global conflict. In essence it balances two potential situations:

• •

the first where there is a high probability of a low level but widely dispersed damage; and the second when there is low probability, while the damage would be catastrophic but to limited targets.

For example, many buildings are sited adjacent to rivers which may flood very occasionally. In case of flood, property owners, or their insurers, face expensive bills to make good the damage. However, the costs of providing flood barriers would be greater than the repair bills for many inundations – and make houses in such situations less attractive to buyers, too, so reducing their value. Risk assessment considers:

• • • • •

the likelihood of an event; the predicted frequency of the event; the potential individual harm of the event; the number of individuals who could be harmed; and the total potential cost.

From objective calculations of these data, it is possible to quantify the risk, and to set that figure against the cost of precautionary measures which could avoid the damage.


It is thus possible to compare the total impact, for example, of fire in tunnels against the costs of providing frequent exit ways. In a similar way, the economic consequences of using expensive earthquakeresistant building techniques in an area with a low risk of earthquake, against those of rebuilding in the event of disaster, can be compared. Care is, however, needed. Simple mathematics may be a poor guide: bear in mind that, although it is mathematically demonstrable that on average anyone is likely to be better off financially if they do not take out insurance (because the insurance companies are in business to make profits), it would be foolhardy to omit to take out insurance for that reason, as few can accept the risk of a catastrophic event. Since it is impossible to put an economic value on personal suffering, this cannot be taken into account, other than in comparing potential fatalities in different scenarios.

Tra d i t i o n To follow tradition does not involve aping the past. It is a matter of respecting the underlying reasons for past practices, and appreciating their application in current conditions. To take a simple example, imagine that the traditional house in an area is a two-storey structure with a timber frame, wattle and daub infill and a steeply pitched clay tiled roof. Such a house would have two interconnected downstairs living rooms, and two rooms above, with probable access to an attic. Three ways of building a new house in that area might be the following:

•

• •

To provide the same kind of two-storey accommodation, in a brick box with cavity walls and a low-pitched clay tiled roof, like those to be found anywhere in the country. There would be a high standard of amenities. Such a dwelling has been found very suitable to an average modern lifestyle. To design a single-story building with a prefabricated timber frame, factory made sandwich infill panels and a single pitch, tiled roof, and arranged to suit the lifestyle of the owners. Using local craftsmen to reproduce a mediaeval structure, but then adding in good insulation, central heating and a modern kitchen and bathroom.

It is at least arguable that the second of these follows tradition most closely, as the tradition is to use the most suitable available materials to provide workmanlike shelter. As the building had an expressed frame it would be more conformable to the local style than the first option, and because of its honesty, it would be more acceptable than the third.

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Simply to build in a pastiche of past models is rarely successful, yet a dilemma arises where a building has to be designed for an infill site in an established townscape. Often there is guidance from the planning authority, but it is informative to consider the different options followed in different places. Some authorities require that a street pattern will be strictly reproduced because in a particular situation they regard the integrity of the facade as more important than the expression of the individual buildings. Few would argue that this should be the case in a Georgian terrace, for example. In other cases, it will be felt sufficient that the major materials and roof line are respected, and in many informal towns this will appear appropriate. Where buildings are not part of a continuous road frontage there is a stronger case for non-conformity, and the placing of a strikingly sculptural building, or a starkly minimalist one, as a foil to a street scene can be effective. What is important is respect for the surrounding buildings, and tradition has much more to do with understanding why they have the form they have than in attempting to reproduce them.

Conclusion The requirements of individuals and minorities within the larger community are rightly protected, but it is important for the general good that the ethos of the society, evolving under the influences of social and technological change, should also be preserved. This implies that, while innovation will frequently be desirable, it will always be seen within the matrix of existing conditions and the values of the environment in which it is set. Innovation will never be sought for its own sake, but will be a response to influences from a myriad of sources and part of the general sweep of evolution.

Part 1

Bibliography Allen, Edward (1980) How Buildings Work. New York and Oxford: Oxford University Press. Chicken, John C. and Posner, Tamar (1998) The Philosophy of Risk. London: Thomas Telford Ltd. French, Jere Lloyd (1978) Urban Space. Dubuque: Kendall/Hunt. Gabel, Medard (1975) Energy, Earth and Everyone. San Francisco: Straight Arrow. Jellicoe, Geoffrey and Susan (1995) The Landscape of Man. London: Thames and Hudson. Kempe, David (1988) Living Underground: A History of Cave and Cliff Dwelling. London: Herbert Press. Lloyd, Nathaniel (1949) A History of the English House. London: Architectural Press. Louw, Hentie (2002) The Place of Technology in Architectural History. London: Society of Architectural Historians. Meier, Richard L. (1974) Planning for An Urban World: The Design of Resource Conserving Cities. Cambridge, Mass: MIT Press. Melville, Ian A. and Gordon, Ian A. (1997) The Repair and Maintenance of Houses. London: Estates Gazette. Padovan, Richard (2002) Towards Universality: Le Corbusier, Mies and De Stijl. London: Routledge. Rostron, Jack (ed.) (2002) Dictionary of Property and Construction Law. London: Spon Press. Rozzoli (trans.) (1971) History of the House. London: Collins.

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Smith, Peter F. (2001) Architecture in a Climate of Change, 2nd edn. Oxford: Architectural Press. Trachtenburg, M. and Hyman, I. (2002) Architecture from Prehistory to Postmodern. New York: Abrams. Tweedy (ed.) (1996) Laxton’s Guide to Risk Analysis and Management. Oxford: Laxton.

We b l i o g ra p h y www.calderdale.gov.uk/build-plan/buildingcontrol/regulations/history.html (22 August 2005) www.building-regulations.org (22 August 2005) www.sra.org/resources (22 August 2005) www.sra.org/risk analysis (22 August 2005) www.ostunithewhitecity.com/puglia/alberobello.htm (22 August 2005)

Part 2 The design team

INTRODUCTION, 47 Chapter 5

THE SPECIALISTS AND HOW THEY WORK TOGETHER, 49 Early professionals, 49 The mediaeval period, 50 The Renaissance, 50 Industrialisation, 51 Working in teams, 53

Chapter 6

THE CLIENT’S ROLE, 59 Objectives, 59 The commission, 60

Chapter 7

COMMUNICATION, 63 Theory, 63 Channels of communication, 66

Chapter 8

PROFESSIONAL RESPONSIBILITY , 75 Codes of professional conduct, 75 Contract, 77 The self-employed consultant, 77 Employees of professional practices, 78 The client’s employee, 78 The design and build team, 79 Summary, 80 BIBLIOGRAPHY , 81

Part 2

Introduction Design professionals cannot hope to work effectively unless they recognise the individual contributions made by specialist colleagues, as well as the techniques through which they can most effectively work together. This Part considers their roles and the parameters within which they operate. In Chapter 5, the evolution of the design professions and the importance of their ability to work as mutually dependent teams is discussed. Chapter 6 considers the involvement of clients in commissioning building work, and what their most productive relationship with the design team may be. The importance of good communication is identified as a key element in the design process and is dealt with in Chapter 7. In particular, there is consideration of the disruptive ‘noise’ which may occur, and the means available to avoid it. The vital topic of professional ethics and responsibility is introduced in Chapter 8.

Chapter 5

The specialists and how they work together E a r l y p ro f e s s i o n a l s As discussed, primitive buildings take the forms they do through the influence of need, climate and available materials. Largely unspecialised builders worked (and work) to provide the simplest possible shelter, from the prevailing conditions, which can be created using the materials at hand. From Ban Po in China to the Orkneys, and from Minoa to Utah, broadly similar circular shelters were made from whatever materials were available. A technology developed as people learned how to use those materials (stone, timber, earth, grasses or snow) to the best advantage, and few specialised skills were required. Named designers were, however, to emerge at a very early stage, where grander buildings were required, though the people concerned can perhaps better be seen simply as members of an educated elite. Imhotep is credited as the priest, healer, poet – and architect – of 3rd dynasty Egypt. It is claimed that he virtually invented the pyramid, having supervised the construction of the Step Pyramid at Saqqara, the prototype of all later pyramids, in the twenty-seventh century BC. Such construction was only possible because of the plentiful stone and the even more omnipresent cheap labour available. Apart from Old Testament accounts and those in the Book of Gilgamesh, little is known of the architects of Mesopotamia, South America or China. Clearly, however, conceptual minds were at work in Babylon, at Macchu Picchu and at Xian. The next team to be noted is that credited with the design of possibly the greatest of all buildings, the Parthenon, under the regime of Pericles in about 440 BC, and in this case real specialisation can be

5.1

50

5.2

THE DESIGN TEAM

identified. Three names are documented. Iktinos is credited as the architect of the building, working alongside Kallikrates, who appears to have had a supervisory role, and who was the city architect of Athens. Apparently Kallikrates was a technical man and he ensured the stability of the building. Pheidias, whose name is so often mentioned, was a sculptor rather than a building specialist, and was in overall artistic charge of the Acropolis.

The mediaeval period The construction of houses and public buildings continued on very much the traditional lines, with local masons and carpenters using the materials and methods common to their districts, and gradually learning to do so in more advanced ways. The artisan determined the form of buildings, according to local need.

5.3

The great cathedrals and monasteries of Europe present a different picture. The important role of the Master Mason, taking his skills from site to site, is vital to the understanding of the huge engineering advances made at this time. These buildings are expressions of the use of small units of stone to span wide spaces, in arches and vaults, and it was the Master Masons’ understanding of the sophisticated mathematics involved in setting out these structures, and in preparing the stones, that made such development possible. Many of the Masons are anonymous, (though their distinctive marks can be traced across Europe) but some, such as William Sens (paralysed when he fell off the scaffolding at Canterbury when on a site inspection in 1175), are recognised.

The Renaissance Renaissance Italy saw a flowering of building inspired by renewed interest in the classics, and driven forward by polymaths like Michelangelo. In Britain, the first Renaissance architect, and so perhaps the first person who can be recognised as an architect (though his impressive title was that of Surveyor General to the King’s Works) was Inigo Jones. Drawing ideas from his travels to Italy, Jones put up Queen’s House at Greenwich between 1616 and 1635. This was the first building fully in the new style in Britain, though Tudor building had been considerable influenced by the new ideas. Christopher Wren, noted as the planner of post-fire London, designer of St Paul’s and of 52 city churches, was a mathematics don, and a

THE SPECIALISTS AND HOW THEY WORK TOGETHER

5.4

5.5

5.6

prolific inventor. He is credited with developing a reliable working barometer. As in the case of his Italian forebears, like Brunelleschi, his engineering skill was combined with considerable aesthetic sensibility, as can be seen in his dome at St Paul’s (1675–1710). It is interesting to compare this visually, and as a piece of engineering, with Brunelleschi’s Dome in Florence (1418). Both Jones and Wren came from lower middle-class backgrounds, but were able to take advantage of education and patronage to find an outlet for their talents.

Industrialisation After the eighteenth century, during which the gentleman architects, or dilettanti, along with the architect with some formal training, came to the fore and with them the distinction between contractor and designer became clearer, there was also the development of speculative building, as in Bath and in Edinburgh New Town. As the century wore on, and into the next, industrialisation became prevalent, and the birth of prefabrication is usually recognised in Paxton’s Crystal Palace, though his work on glasshouses, which predates the Great Exhibition, was seminal.

5.7

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5.8

THE DESIGN TEAM

Some perceived a decline in craftsmanship. This was countered first by the emphasis on applied decoration of the mid-nineteenth century and later, and more influentially, by the anti-industrial movement exemplified by Macintosh in Glasgow and by Art Nouveau. Professionally, the greatest influence was in the development, from eighteenth-century learned societies, of the chartered institutes. Specialisation among building professionals was made essential by the great complication brought to construction through new structural methods. These utilised technologies such as those of cast iron, steel and later reinforced concrete. The development of building services far beyond the dreams of earlier periods was also influential. A further important influence on the evolution of building design in the early twentieth century was that of the Bauhaus, where Walter Gropius and Mies Van der Rohe taught. Here, industrialised production was fully embraced, with no loss of sensitivity. Very simple geometric forms were typical. The Mies Van der Rohe pavilion in Barcelona, recently restored, crystallises this ideal.

5.9

The authority springing from this school, along with the ‘form follows function’ mantra of Corbusier’s followers, in large part created the building design ethos of the century. The later twentieth century saw a flowering of industrialised building, and especially of system building, where all the components from which a building could be assembled were manufactured and purchased as part of a single industrial operation. As a result, interest in dimensional co-ordination developed because this allowed the parts to be made by competitive manufacturers, but to be capable of efficient integration. At the end of the century, and in the twenty-first, three kinds of buildings could be distinguished:

• •

5.10

The sculptural, those on which the organic arrangement of the accommodation determines a dynamic form, as in the case of the Guggenheim Museum in Bilbao (1993–1997) by Frank O. Gehry. The engineered, those in which an advanced structure (such as the hyperbolic/paraboloid) determines the form. The City of London office block at 30 St Mary Axe ( also known as the Swiss Re Tower), 2000–2004, by Foster and Partners) springs to mind.

5.11


•

The technological, those based on three-dimensional modular grids, into which the parts, almost all factory made, slot simply and easily. Most office blocks are of this type.

It may be inferred that these could become the provinces of the architect, the engineer and the technologist respectively, but in every case a balanced team, including members of diverse professions, will be employed. This gallop through the development of the building professions is necessarily a sketched outline. It is included here to facilitate an understanding of the distinctions between the professions and the institutes to which their members belong.

Wo r k i n g i n t e a m s While very small projects may be run by a single professional, and for some medium-scale jobs an effective partnership will be formed between an intuitive designer and a practical technologist, the majority will demand the special skills of a team. In selecting these, it is essential first to consider with some care what the critical aspects of the problem are, and then to identify individuals who will best fulfil each of them. Leadership will depend on the nature of the works. Conventionally the architect leads for most building projects, but this need not be invariable. Where the engineering aspects predominate, an engineer may be key, or if conservation is critical, the role may be best taken by a surveyor, and so on. It is sometimes proposed that the team should be led by a neutral manager. Such a person is difficult to find, among people with sufficient knowledge of the industry to understand the goals, yet who will suppress a desire to contribute to the development of ideas. Increasingly, practices appoint people whose background is in business, qualified possibly to MBA level, rather than in construction or design, as practice managers. Such a person would usually be concerned only with administrative matters, and could take a part in organising the design process. Not every practice would find this ideal. Team membership may be predetermined, for example if the job is being undertaken by a multi-disciplinary practice. In other cases, practices with specialised experience may be called upon. There is some debate about the dangers of over-specialisation. Someone who has spent a career concerned with hospitals may be somewhat set in their ways where ward design is concerned, but may become freely creative if invited to consider the needs of an airport lounge.

5.12

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THE DESIGN TEAM

It is not essential that the team be made up of high flyers – a group with middle-ranking skills has sometimes been thought to perform better than a group of individuals, each of whom is too conscious of the need to maintain their place in the pecking order. A team is defined as a group working together to a common goal. In doing this, it develops synergy. This is the characteristic of a set of parts, when properly assembled, to perform more than the parts could do individually. A football team or a wristwatch are good examples. To achieve this, the team first needs to recognise its goal, then to plot strategies, and after that to establish a schedule against which progress can be measured. The leader has a key role in helping the team to recognise the key issues, to tackle them efficiently and to tackle them in the right order. This is only possible if:

•

• •

the group is bonded by mutual respect, based on an understanding that each member has a unique contribution to make. It is unusual for the kind of group bonding exercise often advocated in a business setting to be needed, but occasionally this may be appropriate; good channels of communication are set up and used; and agreed parameters of timing and cost are respected.

There are various patterns of intercommunication:

• • •

the bunch of balloons (Figure 5.13), in which all report to the leader; the pyramid (Figure 5.14), in which the leader directs the members; or the organic (Figure 5.15), in which there is a general dissemination of information.

The last is by far the most effective, and the only true pattern of team work. It demands regular meetings, for which time is set aside as a priority by all members. If such meetings are not to be repetitive and timewasting, each must be run to an agenda, the decisions taken must be recorded and those decisions must be accepted by all. Leadership is a key issue.

5.13

5.14

5.15


The balloon format assumes that the members of the group are merely present to advise the leader, who will weigh up their advice and make decisions based upon it. For example, the structural engineer might propose a reinforced-concrete form, the mechanical engineer might ask for duct work of particular sizes, and the sound engineer might require a low level of sound transmission. The technologist ‘team leader’ might attempt to satisfy all these requirements, but it is unlikely that he would arrive at the optimum solution. A pyramid arrangement presupposes that the leader, an architect say, has a firm idea of the form he wants the building to take. He states this as a condition, and requires the specialists to evolve solutions to the problems of structure, services and environment which conform to it. The chances that this might throw up a successful building are limited. The greatest chance of success comes when there is interaction between the members of the team. Some authorities have identified discrete stages in the creation and work of effective teams, as follows:

•

•

•

•

Forming – getting to know and to trust one another (this is the stage at which the team games or theoretical problem-solving exercises are sometimes used). In the case of a building project, it may be worthwhile to arrange a preliminary, semi-social encounter, when the members can have an opportunity to express their values and priorities. We all get on best with people if we ‘know where they are coming from’. Storming – the stage at which everyone takes as open-minded an attitude as possible to examining the real problem. It is worth spending time on floating ideas uncritically. There has to be a defined conclusion to this stage, if the fun of it is not to take over. Norming – setting the parameters for serious work. Here, a clearly understood and agreed time schedule is drawn up, establishing the critical stages of each person’s work in relation to the whole. Additionally, because there is a budget for development and design fees, as well as for building costs, the limits of the resources available to tackle each part of the design should be set. It is the responsibility of each member of the team to understand and accept the limits, in time and cost, which have been put upon his contribution. Performing – getting on with the job. Everyone knows what they must do by what dates, but nonetheless they must attend meetings ready to report, to receive the reports of others, and to modify their own work where compromise is necessary. Otherwise this is not a team. If it becomes evident, between meetings, that a problem affecting the work of others is arising, an informal contact should be arranged. The outcome of such a meeting should be reported at the next formal meeting, but

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THE DESIGN TEAM

•

should not be regarded as final until it has been examined and agreed by all. Once formal decisions have been taken, they must be regarded as final.This makes it clear that the order in which decisions are to be tackled is paramount.The most influential issues (siting/structural system?) must be taken first.Any re-examination of such factors will undermine all subsequent work. Adjourning – the difficult point at which it has to be admitted that the task can be taken no further.There is always a chance that a further iteration of decision making might throw up a better answer.A practical limit has to be set, not only to small decisions during development, but also to the overall outcome of the group’s work.

Groups which work properly develop synergy purposefully, share out the work so that everyone has an identified role, and collect ideas. Decisions are made co-operatively.Their work is controlled by testing each other’s ideas against those of the rest, and by accepting corporate decisions.The strength of the group develops because the participation of each member is respected.

•

An effective group clearly understands its purpose and goal.

•

It (the group) is flexible in selecting its own procedures to achieve these goals.

•

A high degree of communication exists, including understanding and transmission of group members’ feelings.

•

Effective decision making, with all the group carried with the collective decision.

•

There is a balance between group productivity and individual needs.

•

A sharing of leadership, with all members contributing ideas, opinions etc.

•

A high degree of cohesiveness can be experienced but this does not stifle individuals.

•

An intelligent use of different abilities.

•

No domination by a leader or others of the group.

•

Obje ctivity in reviewing its own processes and it can be adaptable to new circumstances.

•

A balance between emotional and rational behaviour. Channels emotionality for the group. David Langford, 1957


It is the job of the leader to facilitate this process, but not to impose decisions. However, he or she must ensure that the work moves forward efficiently, and therefore a major part of the role is to be aware of the set parameters and to match progress against them. The group must be alerted to points at which there is a need for compromise and ensure that everyone accepts the limitation of the process.

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Chapter 6

The client’s role Objectives W hile not part of the design team, the client, of course, plays a vital part in defining the project.In the case of smaller work, ‘the client’ may be a single person who will be investing his own funds, running the building and occupying it.This is unusual.The individual who acts as client is generally an identified person (sometimes a committee) who does not speak personally but whose role is to interpret the requirements of the investor, the administrators and the potential users of a building. The perceptions of each of these groups may well be different. The financial backers of a project need, above all, to ensure that their capital is safe and that they will receive a reasonable return on it, either in the form of rental income, efficient operation or of increasing value. They have a responsibility to their shareholders, which they will see as primarily important. Those who administer a building have different concerns.They will be thinking less of capital growth than of cash flow. Straightforward maintenance, durability and simple access for repairs without parts of the building being temporarily sterilised may well be among their priorities. The people who actually use the premises on a daily basis, and for whom it houses vital functions, expect high quality, attractive appearance but, above all, convenient and logical layout. An additional need is, usually, that the building should make a clear and recognisable statement of identity, a feature often seen in corporate headquarter buildings.This can be in conflict with the desire for townscape conformity.It may also be thought desirable that the purpose of a building should be clear to passers-by.This does not, in any

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THE DESIGN TEAM

way, mean that resort need inevitably be made to symbolic features that remind the public of traditional buildings with the same purpose, such as a Moorish dome identifying a mosque. The client’s spokesman has to examine these varying requirements and prioritise them.He or she has the delicate task of obtaining the approval of all the groups to their perception of the correct balance, in that particular case, of investment, running costs and convenience.This balance could be weighted in favour of the users in the case of a hospital, in the direction of the financiers where a speculative office block is concerned, or for the administrators in the case of lettable housing.

The commission Every building project starts from a commission, which is a simple statement of purpose, site and available finance, all of which are defined by the client.W hile the design team will have an important role to play in helping determine the detail of the building’s functions, and the viability of the cost and time limits that have been set, they must, in the long run, accept the client’s parameters.W hile they may need to point out that these targets ought to be revised, these matters are the responsibility of the client, and once agreed must be respected. The commission, which is based on the kinds of considerations discussed above, is a simple document made up of just three elements: the functional requirements, the cost limits and the time constraints.

Functional requirements It is up to the client to state how the building is to be used, but not what accommodation is required or how it should be arranged.If he or she is inexperienced, the client will find this hard to achieve.The client will think in terms of rooms of particular sizes, of ground floors and upper floors.He or she may have preconceived ideas, based on knowledge of existing satisfactory or unsatisfactory buildings of a similar type. It may also be the case that, rather than stating the levels of temperature and other environmental parameters to be achieved, the client thinks in terms of a particular kind of plant.Techniques by which the client can be encouraged to state a problem rather than attempt its solution, will be explained later.

Cost limits The client knows how much money there is in the budget, and must be trusted to have done calculations of the cash flow through the life of the building.The client’s stated limits must therefore be taken seriously.

THE CLIENT’S ROLE

It is part of the duty of the team to keep these agreed limits in mind, to expect to work within them, and to draw the client’s attention at once to any circumstances which appear to indicate a possible overspend. Diligence is needed to achieve this, and procedures (of a kind to be discussed later) should be in place to ensure that it occurs.

Time limits The date by which completion is required is intimately linked to the cost flow calculations.The technique of ‘discounted cash flow’ allows the calculation of the value of a future purchase, based on the amount that needs to be set aside now, in order to fund it at a later date. A brief example of this method is included in a later section, and it, and others related to it, will be discussed in detail in Volume 4 of this series, Practice, Management and Responsibility.Such techniques refer to the decisions that have to be taken in any business if it is to remain solvent. The owner of the building has also to take into account the income that the completed premises will generate, or the saving on the running or renting of less convenient spaces.He or she may be dependent on government or other grants which are time limited. For these reasons, as well as others such as the planning of a prestigious event, it is essential that proper account should be taken of the cut-off date, and schedules have to be prepared by which progress can be measured and early corrective action taken on any slippage.If additional cost is involved, this must be put into the equation.

The site Identification of the site also falls, normally, within the responsibility of the client, though the client may well ask for advice as to the suitability of the land he or she has in mind.Members of the professional team are not generally involved in the business of land transfer, at least where their role in the present context is concerned.

The brief The development of the commission into the (misnamed) brief will be a co-operative exercise, in which the client’s representatives will be helped to flesh out their bald statements.This will be discussed in a later section. Once this has been done, it should be possible for the client to forget the project until the day comes to take possession.The client has no further role – but of course he or she will always be interested in progress, anxious to receive reports and pleased to be invited to visit the work. It is important that the client realises that the site belongs to the builder, and that the client should not visit unasked.

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Chapter 7

Communication

It is a common experience to hear someone say ‘It would be easier to do it myself, than to explain it to someone else!’.Most of us find it hard to know when we have got our meaning across properly, and the effort of making oneself clear may seem disproportionate when the task is a minor one. In a professional world, where team working is not just inevitable but essential, learning how to communicate effectively is a basic skill.

Theory Effective communication depends on effort and understanding from both the initiator of the message and the recipient.Both need to be well aware of this. It is all too easy for someone whose instructions have been misinterpreted to blame the recipient, while the one who misread the message is sure to blame the sender. A message can be thought to consist of the material to be communicated, the language in which it is couched, and the channel of communication chosen.Any factor which interferes with its transmission from source to destination is ‘noise’, and noise not only distracts but can distort sense, with expensive and time-wasting effects.It is to everyone’s advantage if as many sources of noise as possible can be eliminated. Ambiguity and confusion may originate within the content of the message itself, particularly if it is excessively elaborate. It is always best to simplify, to ensure that only the intended topic is covered, and that nothing extraneous could be inferred from the content. Another source of noise is often the use of an inappropriate code.This can happen if an attempt is made to convey a highly visual concept in

7.1

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Knowledge

Knowledge

Skill

Skill Message

Culture

Code

Culture

Presentation Attitude

Attitude

Status

Status

7.2

words, when a simple drawing would be more suitable, or if a telephone call, with no paper follow-up, is relied upon for a complex instruction. It is also important that the code should be identified clearly, so that the recipient can understand the message from the outset.However beautifully the message is framed, there are still potent sources of distortion. There are barriers between both the communicator and the message, and between the message and the communicatee, which affect their perceptions of the message, and are therefore liable to distort it in transmission. One can conceive these barriers as being in the nature of filters, through which the communication has to pass. Five elements have been considered to contribute to each barrier, and the message will pass most easily when the elements of each filter are in harmony. These are as follows:

•

Skills.The person conveying the message needs to be fluent in the language used, whether that is English grammar, technical drawing or simply handwriting: – speaking face to face and good diction are essential; – when making a graphical presentation, it is necessary to have command not only of the use of the tools (pencil, pen or computer) but a grasp of the symbols and their meaning;and – letters and notes need to be carefully worded to avoid ambiguity. Similarly, the person receiving and interpreting the message can only do so correctly if they are equally fluent in the language used.They, too, need to be sure they have heard correctly, understand the technical terms that are used and follow the meaning of symbols. (One case is known when a carefully drawn north point, intended only to orientate the building, was laid out with

C O M M U N I C AT I O N

•

•

•

•

equal care on the paving at the entrance to a prestigious company headquarters.) Culture.W hen we encounter a visitor from abroad, we are at pains to ensure that differences in culture do not obscure our meaning, or our understanding of them.e Wmake a special effort to ensure good communication.e Wspeak to children on the basis of their known experience, we take the environment in which they find themselves into account when visiting elderly relatives in residential homes.e Ware not always so careful where our colleagues are concerned.Yet the perceptions of a surveyor, an engineer and a business man client as to the priorities in particular circumstances can vary widely, because their cultural base is different.It can be salutary to ask oneself whether everyone met at work means the same thing by ‘good brickwork’. Knowledge.It is always dangerous to assume other people know something because it is second nature to oneself, but it is a thing we do all the time.W hat we think we know is not necessarily common knowledge.It is, clearly, inevitably dangerous to take a vital safety point for granted.It could be expensive to assume that others were aware of the requirements of a local authority in whose area they did not usually work.Similarly, when we receive a message, we mustn’t always assume that the author knows of the lawsuit that’s pending, or the potentially treacherous ground conditions, although these are not referred to. Status.Those who believe themselves to be in inferior positions are liable to read guidance as draconian instruction.Those who perceive themselves to be in charge may be reluctant to accept comment.Both need to be alert to this, however good they believe their relations to be, because good communication can be subtly damaged where the possibility is not understood. Attitudes.Differences in our responses to situations, including our scale of values, can make a fifth potential hurdle between sender and recipient.e Wall have prejudices, though we often do not recognise them, and we should try to identify them so that we can allow for them before misunderstandings occur.

Noise Noise can also be introduced quite extraneously, if not always inadvertently, through lack of care.Poorly chosen letterheads, pompous email signatures, poorly groomed staff at formal meetings, and a cavalier attitude to punctuality are all effective portcullises.In the case of every attempt at communication, the following points should be clearly understood:

•

the objective, the message, and the need to eliminate redundant material;

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7.3

• •

the recipient, and the conditions under which the message will be received and used;and the competence of both originator and recipient in using the language and method of transmission.

Channels of communication

7.4

There is not space in this book to deal in detail with all the many communication channels used in the industry, though all those identified in Figure 7.3 should be considered and used by practitioners with equal care.Below are some salient points referring to a few of those in most widespread use.

Oral Fo r m a l m e e t i n g s In addition to the regular design team meetings referred to above (in Chapter 5), there will be clients’ meetings and site meetings, as well as others with planning authorities and so on.A formal meeting should always be based on an agenda, which is sent out with copies of all the


reports which are to be the basis for discussion, giving reasonable notice of the date, time and place. It is good practice for the agenda to indicate the period set aside for discussion of each matter, and the time at which the meeting is expected to end. The business should include, where appropriate – and always in the case of the first meeting of any group – a statement of the terms of reference, and a declaration of any limits on the decision-making powers of the people present (whether they need to refer to a higher authority, for example). The chair is often taken by the senior representative of the body convening the meeting, though it is more important that the chair has experience of formal meetings and the skill to allow all parties to make relevant points while curbing repetition and irrelevant matter.The minutes (see below) should be taken by someone not taking part in the discussion. It should be taken for granted that mobile telephones and bleepers are switched off.

Informal meetings It is frequent for people to rely on oral agreements reached during casual encounters.Good practice will ensure that all such discussions are confirmed in writing.If such a note is not challenged it can be relied on as constituting an agreed decision.

Te l e p h o n e c a l l s a n d e m a i l s Similar considerations apply in the case of telephone conversations.It is good practice to keep hard copies of emails, in case of computer failure.Systems managers often clear the inboxes of web members.

Written Minutes and records Above, there was emphasis on the importance of formal meetings. Such meetings only truly fulfil their purpose if readily accessible and transparent minutes are kept.One trap that it is all too easy to fall into is to attempt to make verbatim records of everything that is said.W hat it is generally necessary to record is:

• •

• • •

who attended and who sent apologies; the reading, or taking as read, of the previously circulated minutes of the prior meeting and their acceptance, or agreement to any amendments.The record can then be relied on to resolve any later disagreement as to what has been decided; decisions reached as to matters arising previously; reports on action taken since the previous meeting; matters raised for discussion and decisions reached, including actions to be taken and by whom.There is no need to include

7.5

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• •

details of the discussion, unless someone asks for a dissenting opinion to be noted; date, time and place of the next meeting;and distribution list for the minutes.

Minutes should always be circulated as soon as possible.It is very bad practice to leave them to be circulated with the agenda of a subsequent meeting, as this allows little opportunity for them to be considered before being agreed.

Letters and memoranda Ideally, letters should be written from organisations to organisations, that is to say: ‘Messrs ABC, (for the attention of DEF) Dear Sirs xxxxxxxxx xxxxxxxxx Yours faithfully (signature) (TUV) on behalf of X YZPartnership’ although the norms of some organisations may override this. Memoranda are more personal, and can be from Fred to a Jne, though text messaging jargon (‘Hiyah J ane, I C U R bck’) is to be avoided. Copies should be kept.

Specifications Specifications are vitally important documents, and are referred to in detail in Volume 3, Materials, Specification and Detailing. It is necessary to say little more here than that they should be treated for what they are, legal documents.Their purpose is to define:

• • • •

the nature and extent of the work to be included in the contract; the conditions under which the work will be done; the quality of the materials and workmanship which is acceptable and the tests which will be applied;and the sanctions which will applied for non-conformity.

The language used must of necessity be precise, but it should never descend into impenetrable jargon.Any words which are not in common use, or which are used in other than their everyday sense, should be defined.The specification must never contradict the Contract.


7.6

7.7

7.8

W here a Bill of Q uantities is to be the basis of a Contract, it remains the responsibility of the design team to prepare the specification on which, together with the drawings, the Bill will be based.This task should never be delegated to the Q uantity Surveyor alone.

Drawn S ke t c h d r a w i n g s As has been emphasised elsewhere, design happens in heads, not on paper. However, sketches are a powerful way of conveying concepts between members of the team.They can be confusing unless they are kept simple – only one idea should be included in one sketch.Clarity is sometimes helped if analogy is used:

• • •

in Figure 7.6, relative scale is expressed; in Figure 7.7 the importance of the transition from a dark to light space is emphasised;and in Figure 7.8, a simple statement about the nature of an auditorium is explored.

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Sketches are rapidly made and disposable. In this, they differ from the sketch design, which provides a full conceptual idea of a design solution, for discussion between members of the team and eventually for presentation to the client.This shows, as graphically as possible, what the nature of the building would be in relation both to the experience of the users and its place in the environment. The kind of skills involved in providing an accurate presentation of the proposals to readers unused to reading technical drawings are specialised, and may well include computer visualisations and physical models.These are all intended, above all, to sell the design, though never at the expense of accuracy. The ‘rendering’ of elevations, and the preparation of fully coloured perspective drawings of sketch designs are less common today than they once were, but may still be needed where public exhibition is required.

Production drawings The drawings from which a building will actually be constructed have an entirely different intention from the sketch design, and have to be devised from the outset with that in view.Their purpose is to ensure that the parts of the building are accurately assembled in the intended positions, relative to one another and to the site. Their most important feature, therefore, will be the three-dimensional framework to which all sizes and positions are related.The drawings will typically include:

7.9


7.10

7.11

• • • •

location or site plan, showing orientation, ground floor-level relative to Ordnance Datum and position relative to site boundaries; floor plans, showing the major structures, dimensioned either overall or by relation to a dimensional grid; sections showing all major changes of level, with levels relative to ground-floor level; details of all components, indicating the ways in which they fit together.These can include three-dimensional assembly drawings and exploded views.The subject is exhaustively covered in Volume 3, Materials, Specification and Detailing , so that little need be included here. However, it should be remembered that the details are the primary and essential sources of information on: – dimensions of components, including tolerances; – joints between components;and – the relationship of components in space to a standard threedimensional grid, where one is established.

Many professional offices keep banks of standard details, which have been used and proved repeatedly.This does not preclude the frequent

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necessity of reappraising such material, and preparing new details to meet new contingencies.

Service layouts These are usually prepared by consultants, but need to be carefully coordinated one with another, and with the general drawings, to avoid clashes.

Assembly drawings These show how all the components are co-ordinated and these are produced to assist, and to be consulted in case of dispute, but should not override the drawings identified above.W hen they are prepared, any inconsistencies should be ironed out and the specialised drawings amended accordingly.

Interior design and landscaping drawings The production drawings, amplified by the Specification, form the basis for the Bill of Q uantities.W here PC sums are included in the Bill of Q uantities, consistency with the drawings is a condition of the specification for each product or service.

Record drawings It is poor practice to rely on the production drawings for the use of the client. He or she requires a set of documents which assist him/her in running the premises, and in which service runs (especially cut off points), identification of manufacturers and catalogue numbers of components take priority. W here it is possible to provide a complete users’ guide, which includes instructions on the use and maintenance of plant, the cleaning of materials and so on, this should be done (see Part 3, Chapter 14).

Models S ke t c h m o d e l s During the development of a design it is frequently helpful if rapid disposable models of complex three-dimensional forms can be produced. These do not need to be engaging, but are used to reveal any odd conjunctions that may arise from the unusual assemblies of forms. Figure 7.12 is an attempt to demonstrate the importance of models in describing something that cannot be well conveyed in a drawing or words.The only simple way in which the reader will make sense of it is to make a model. First, four identical copies of an isosceles triangle surrounded by right angled triangles, as shown at A, should be cut out.Two of these shapes


7.12

should be formed into triangular pyramids (B).From the other two, a hexagonal three-dimensional form (shown in plan and elevation at C) is made by joining the edges of the right-angled triangles of the two shapes. Most people are quite surprised to discover that the three solids now assembled can be fitted together to make a cube (D). It is virtually impossible to make either an orthographic or a threedimensional drawing that a craftsman could use to reproduce the central element of these three shapes.If he or she were given a model, the form would be immediately apparent.

Mock ups Even more useful may be full-scale mock-ups of critical repeating components, from windows/structural frame assemblies to hospital bedbays and whole structures, so that they can be fully tested.This can, in some cases, include laboratory or wind-tunnel testing, in which case-specific considerations will apply and the advice of the laboratory must be taken.

Presentation models Realistic scale models can be a powerful marketing tool, especially where public approval is sought.They are expensive to produce and cumbersome to move and to store, and so should only be used where there is an excellent reason. It is important to determine in advance what effect is required (for example, to engage sympathy by showing how well a building would sit with its neighbours, or to project a forward-looking vision).The choice of materials and general presentation will be greatly influenced by such factors. In fact, the skills of the advertising world need to be engaged.

7.13

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C o m p u t e r- g e n e r a t e d m o d e l s The manual preparation of perspective drawings and physical models is increasingly being superseded by the generation of computer presentations. In particular, walk-throughs have considerable advantages over physical models in that they remove much of the doll’s house charm of the miniature, in favour of a more realistic experience.

Computer-aided design A computer is a powerful and versatile tool, in the same way as a pencil and sketch pad or a drawing board and t-square. It can no more produce designs than they can.

7.14

Indeed, computer-aided design (CAD)has serious limitations. While it may well be true that an application capable of drawing the subtle sophistications of the Parthenon in Athens, or the exuberance of Gaudi’s Sagrada Familia in Barcelona, could be developed, the technology is likely to be beyond the reach of most offices –and beyond the desires of imaginative designers. CAD will, supposing the appropriate data are input, produce speedy calculations which can be the basis for structural and environmental decision making. Complex modern structures like Wembley Stadium (Foster and Partners and HOK Sport, 2004)would be impractical otherwise. It cannot make the decisions, which require the application of professional judgement. CAD is discussed in detail in Volume 3, Materials, Specification and Detailing. It is not possible, in the scope of this book, to discuss the packages available. It is important, however, to guard against becoming computer dependent.

Fi l i n g What matters about a filing system is that it allows any record or drawing to be found quickly. Date order may not always be more efficient than collection by topics (for example as is done by ‘Dewey decimal’ in libraries), but whatever system is adopted should be understood by everyone who may need to consult the records. If a nominated filing clerk is employed, that may not mean everyone in the office. The most usual classification for building media is CI/SfB, which is a development of the Dewey decimal system. A survey of this can be found in the Royal Institute of British Architects (RIBA)Library website.

Chapter 8

Professional responsibility C o d e s o f p ro f e s s i o n a l c o n d u c t It is one of the distinguishing marks of any profession that its members are subject to discipline by their peers.The Codes of Professional Conduct of the institutes relevant to the construction industry share many characteristics, but one should not extrapolate the demands of one from those of another profession.These codes evolve through the years, often as a result of case law, and in any specific case the current requirements of the institute involved must be consulted. The detail of the Codes of Conduct of the Royal Institute of British Architects (RIBA), the Royal Institute of Chartered Surveyors (RICS) and the Chartered Institute of Architectural Technologists (CIAT) are dealt with in Volume 4, Practice, Management and Responsibility , in this series.Four requirements are more or less universal, at any rate within the professions concerned with the built environment, although differently phrased from code to code:

•

Members are expected to act with due diligence, providing proper standards of professional skill. This does not mean that their performance must be equal to that of the most skilful or diligent in their profession, but that they will only take on work they are competent to perform, will spend enough time and attention on the task to perform it properly and will take personal responsibility for it.If anything goes wrong, they are bound to do whatever, or pay whatever, is necessary to put the matter right, to the reasonable satisfaction of the person or body who commissioned the work. As a corollary, they are usually required to carry expensive professional indemnity insurance so as to be in a position to recompense their clients for added expenditure, should a problem arise,

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•

•

•

or cover their damages (including legal fees) in case of claims by third parties against the client for injury or damage. Additionally, it is part of this requirement that members keep up-to-date with rapidly developing technology, and a commitment to a programme of continuous professional development is nowadays usually obligatory. It is axiomatic that members will not act to the detriment of their fellow professionals.This is often interpreted in precluding anyone from criticising the work of a fellow member of his or her profession, unless he or she is an acknowledged critic or an assessor of some kind.This is generally too sweeping:criticism can, after all, be constructive.Such comment would usually only be taken to be in breach of the code if it affected the chances of the person criticised of getting further work, or brought unjustified public opprobrium upon them. Anyone invited to comment on the work of a colleague should always ensure that the person who, or whose work, is to be criticised is fully informed that this is to happen, and has the opportunity to see and reply to the comments.It is courteous to inform the person in advance of publishing the remarks, so that he or she has a chance to put his/her own side of the case straightaway. The requirement also carries the obligation to avoid unfair competition to get commissions, though members are generally no longer tied to mandatory fee scales.Touting for work is frowned upon, and the extent of advertising allowed is somewhat limited. Members are expected to exercise a duty of care for the public interests. A major part of this requirement is that the relevant law must be understood and adhered to. Ignorance of the law is not a defence. The internationalisation of building has complicated the position.There is an increasingly common pattern for designs to be prepared under one jurisdiction for buildings which will be erected elsewhere, within or without the European Union, and local law must be consulted. Under whatever legal system, it is also necessary that nothing which endangers the public should be done, even if the action is within the law.Any engineer whose structure collapsed, injuring passers-by, would be in breach of their public duty, and liable to punitive damages. Care for the environment, though this can be difficult to define, comes under this heading, too. Conflicts of interest are to be avoided.This makes it unacceptable, for example, for a director of a white goods firm to include the appliances they manufacture in a specification, without providing the opportunity for other firms to compete.It is generally unacceptable for a professional to have a financial interest in a building firm which he or she commissions.

PROFESSIONAL RESPONSIBILITY

C o n t ra c t Once a contract is entered into between client and builder, a further issue sometimes arises.The contract will appoint the lead professional as an arbiter between the parties to the contract where any dispute arises as to whether the contract is being carried out properly.The client, who has understood that this person was appointed to act solely in his or her interests, and who is paying them, may be dismayed to find that the contractor is being supported rather than the customer. An example of a situation where this could arise might be a client with a higher expectation of the quality of materials than was described in the specification.It is important that the client understands that if an unusually high standard is required, this must be made explicit before documents are prepared or tenders invited, because the work approved on site will be that covered by the contract, and not something different.The professional adviser will support the contractor in providing work to the standards described in the documents, even if that means appearing to be on the side of the contractor.

The self-employed consultant Codes of Professional Conduct mainly seem to have been written with the principal in practice on their own account in mind.Such a person may be expected to belong to a local branch of the institute, and to know, respect and co-operate with their peers.Someone in that position is also in control of their own actions and should not find it difficult, if honourable, to avoid unacceptable behaviour. If a member contravenes the rules, they will be taken before the profession’s disciplinary committee, and will expect to be admonished, probably publicly exposed, and even to lose the right to practise. Members of a profession understand and accept such sanctions as being in the interests of both the profession and public. W here clients are concerned, the practitioner will enter into contracts of engagement which reflect the behaviour envisaged by the code, and if asked to take inappropriate action, will be in a position to refuse. Conditions of employment will also be established for the professional staff of the practice, which take fully into account that they have similar obligations.They will act in the name of the principal, will take responsibility on their behalf – and be unsurprised if a contravention of normal professional behaviour is met by sanctions.

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E m p l o y e e s o f p ro f e s s i o n a l p ra c t i c e s People who are employees will find themselves, additionally, subject to the social mores of the organisation to which they belong.These can be summarised to include the following:

•

•

•

• •

The vocabulary, greetings, social interaction between peers, and with seniors, juniors and members of other departments, which are usual.The level of formality prevalent and the dress code may be different from what one has experienced previously, while they are not expressly spelled out.The smooth running of the office is greatly lubricated by conformity to the prevailing norms, and so some sensitivity in discerning what they are is desirable. People are generally paid a salary for a stated number of hours’ work in the week or month.Expectations vary, however: — in terms of acceptable time taken for refreshment breaks and time spent chatting;and — in the case of visits to the doctor, are staff expected to work twice as hard to make up the time, or are actual hours irrelevant so long as the allotted task is completed satisfactorily? Expectations vary as to the degree to which private life is to be subjugated to the interests of the firm. May staff expect to take time off (assuming it will be compensated for as above) for a child’s school concert, if there is an important meeting planned? It should not be necessary to state that there will probably be a formal code requiring the avoidance of discrimination on racial, gender or other grounds. Possibly, loyalty to the organisation is the most basic requirement. However, this last point has to be considered seriously.If there is any chance that obligations to one’s profession and loyalty to an employer might clash, the matter should be taken to one’s line manager and, if necessary, advice should be sought from the employee’s professional institute.

Any of these issues may seem to be in tension with professional independence.It can be difficult to drive against the prevailing environment, if one perceives a conflict between the highest professional standards and what is happening in the office, because there is a clash of loyalties. W histle-blowing is de rigeur if a contravention of professional standards is perceived, but this duty has to be exercised with responsible care – false accusations can destroy professional reputations, and can be hazardous to the initiator in terms of legal proceedings.

T h e c l i e n t ’s e m p l o y e e Additional factors may affect the performance of people who are employed as ‘in-house’ professional staff of a large, particularly a

PROFESSIONAL RESPONSIBILITY

statutory, organisation.This is an increasingly common arrangement today.Government and quasi-governmental bodies build-up specialist teams to undertake their professional work.The members of the various internal departments learn to know each other well, and in theory to work together effectively.They amass an archive of relevant experience and information.There are three main areas of which it is wise to be aware:

•

• •

The specialist client.The client’s expectations that his or her wishes are paramount will be exacerbated.They will be very experienced in commissioning specialised work, less likely to accept advice, and more likely to assume that the professional should argue for them in any dispute with the builder. Clash of loyalties. Loyalty to such an organisation, when a wholly specialised career within it is anticipated, may be particularly strong, making whistle-blowing especially difficult. The optimum team. The people appointed to work in professional roles will have been handpicked, and should be expected to work together happily.This is not always the case, for various reasons: — they may easily fall into practised paths and find fresh thinking on a problem more difficult; — they may have worked together on previous projects where they found each other difficult;and — the team-building activities described above (in Chapter 5) will have been pre-empted, removing a helpful engine of creativity.

The design and build team W here a developer has, for what are good reasons of commercial efficiency, decided to offer a design and build service, and therefore to employ professionals in-house, there are even further considerations:

•

•

•

Commercially driven. The imperative to be profitable must, in such cases, be paramount.This affects decisions taken in connection with a very wide spectrum of topics, such as the choice of a structural system which the developer favours, or the requirements of a sales staff.None of these need make it impossible to take sound professional decisions, so long as they are accepted as being among the parameters of employment. Identifying the client. It is generally necessary to accept the briefing given by the developer, developed from his commercial experience, and unusual to have the opportunity to consult the end user of the premises.This can be frustrating, as it limits the possibility of innovation. Special care is needed to avoid conflicts of interest.

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Summary Members of professional design and supervision teams in the construction industry do not have a free hand to use their own judgement. In addition to the limitations arising from team work, they are subject to what are generally benevolent checks and balances.These include:

• • •

the expectations of the professional bodies to which they belong; the law of the land in which they practise;and the requirements of their employer.

Part 2

Bibliography Acland, Andrew Floyer (1997) Perfect People Skills. London: Random House. Chartered Institute of Architectural Technologists (2003) Code of Professional Conduct. London: BIAT. Goslett, Dorothy (1971) The Professional Practice of Design. London: Batsford. Hendy, C.B. (1976) Understanding Organisations. New York: Reinhold. Langford, D.A. (1987) Human Relations (Design Technology Project). Sheffield: Pavic. Linton, Ian (1988) The Business of Design. Wokingham: Van Nostrand Reinhold. Royal Institute of British Architects (1997) Code of Professional Conduct. London: RIBA. Sharman, David (1993)The Perfect Meeting. London: Random House.

Webliography www.dca.ca.gov/pels/conduct.htm (22 August 2005) www.eyelid.co.uk (22 August 2005) www.gmu edu/student/csl/5stages.html (22 August 2005) www.grad.niu.edu (Code of Professional Conduct in US, engineers) (22 August 2005) www.greatbuildings.com (22 August 2005) www.londonnet.co.uk (22 August 2005)

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www.salisburycathedral.org.uk (22 August 2005) www.teamtechnology.co.uk (22 August 2005)

Professional institutes and institutions Architects Registration Board: www.arb.org.uk (22 August 2005) Chartered Institute of Architectural Technologists: www.ciat.org.uk (22 August 2005) Construction Industry Council: www.cic.org.uk (22 August 2005) Chartered Institute of Building: www.ciob.org.uk (22 August 2005) Institution of Civil Engineers: www.ice.org.uk (22 August 2005) Institution of Electrical Engineers: www.iee.org.uk (22 August 2005) Institution of Mechanical Engineers: www.imeche.org.uk (22 August 2005) Institution of Structural Engineers: www.istructe.org.uk (22 August 2005) Royal Institute of British Architects: www.riba.org.uk (22 August 2005) Royal Institution of Chartered Surveyors: www.rics.org.uk (22 August 2005)

Part 3 The design process

INTRODUCTION, 85 Chapter 9

CREATIVE PROBLEM-SOLVING, 87 Defining the problem, 87 Analysis, 89 Synthesis, 90 Development, 91 Communication, 91 During construction, 91 Summary, 92

Chapter 10 THE PROBLEM, 93 Developing the commission into a brief, 93 Functional requirements, 93 Cost limits, 95 Time limits, 97 The site, 97 The brief, 101 Evolving a design, 102 Communication, 106 Contract documents, 106 Chapter 11

THE PROCESS IN ACTION, 107 Case study 1 – Instant shelter, 107 Case study 2 – A private house, 108 Case study 3 – A teaching block, 112

Chapter 12 AESTHETICS, 119 Introduction, 119 Unity, 121

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Proportion, 124 Balance, 127 Rhythm, 128 Massing, 129 Style, 131 Decoration, 131 Colour, 131 Selection, 135 Chapter 13 EVALUATION, 137 Aesthetics (‘delight’), 138 Function (‘commodity’), 139 Technology (‘firmness’), 140 External scrutiny, 141 Overall, 142 Chapter 14 COMPLETION, 143 Practical completion, 143 Owner’s manual, 144 BIBLIOGRAPHY, 147

Part 3

Introduction Design is not an arbitrary activity. If it is to be practised as a professional occupation it is essential that systematic methods should be adopted.This Part describes an objective approach to building design based upon careful appraisal of the practical req uirements, the conditions under which the building is to be constructed and will operate, and the time and financial restraints which apply. Chapter 9 discusses creative problem-solving as a controlled techniq ue applicable to large and small design problems. In Chapter 10, the analysis of the problem is considered, with ex planation of appropriate strategies to determine the parameters within which the solution must be found, including those of time and cost. Chapter 11 describes some simple case studies which demonstrate the application of such strategies in single designer and team situations. Chapter 12is a brief consideration of aesthetic principles, treated as objective measures of ex cellence, while Chapter 13 discusses the evaluation of proposals against the established req uirements. Finally the completion of the project is considered in Chapter 14, including a discussion of the important documentation which should be given to the client with the competed building.

Chapter 9

Creative problem-solving It is of the greatest importance to understand that finding the optimum solution to a design problem is a systematic process.Designers do not wait for inspiration to strike, they apply tested methods. Neither do they draw a pretty picture and then decide how the effect they want can be produced.An influential twentieth-century designer said: ‘When I am working on a problem I never thinkabout beauty. I only thinkabout how to solve the problem.But when I have finished, if the solution is not beautiful, I know it is wrong.’ R.Buckminster Fuller engineer, designer, architect (1895–1983) Whatever specific techniq ues are selected in a particular case, design procedures will fall into the same series of stages, each of which has to be completed thoroughly before the nex t is attempted. The process which is recommended here is a systematic approach known as ‘creative problem-solving’which is applicable to much decision making in many spheres, but particularly appropriate where a complexproblem involving many specialisms is concerned. It works very well in the case of designing buildings.The diagram in Figure 9.1 outlines the process which will be followed.

D e f i n i n g t h e p ro b l e m To get a proper grasp of the nature of the problem involves collecting all the available data about the req uirements of the client, the conditions under which the design has to be made and the eventual building to operate, and the means available to fulfil the req uirements in that environment.

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9.1

For ex ample, an ex ercise is sometimes done where small groups of students are invited to imagine that they belong to a multi-skilled party intent on setting up a community on a presently uninhabited island off the Scottish coast.They are to aim for self-sufficiency, and may take a single boat load of materials and tools of their choice with them They have to plan for short-term shelter and for the form their buildings will take in the long term, and this involves them ex amining the resources and climate of the island, auditing their skills, and developing plans and building methods which are within their competence, will meet the conditions in which they are to live, and use the very limited local materials.They also, incidentally, find that they have to set up a simple decision-making system and develop a code of rules to control the use of resources by individual family units.They very soon discover that they can only make any progress at all if they first discover as much as they can about the conditions under which they will have to work.

9.2

C R E AT I V E P R O B L E M - S O LV I N G

In the same way, it is misleading to follow preconceived ideas in the case of a more sophisticated proje ct until all the relevant data are available.These will come from many different sources and from bodies with varying priorities. When the whole of the information has been collected, this constitutes the detailed brief for the building.Sources of information are considered in Chapter 10 as well as in the specialised Parts of the book.

Analysis All of this material must be recorded in a systematic and accessible way, and the time allowed for it to be considered as a whole, before further development is attempted. The nex t stage is inevitably the consideration of the data, so that the internal influences can be determined.The materials which can be used may be limited by the budget –and possibly by planning regulations. The client may have stipulated a time limit for construction, which might enforce the choice of a specific structural system, and so on. Each of the specialist members of the design team will have contributions to make to the analytical process.Each may well see the priorities from a different point of view, and it is vital, therefore, that the needs of the project are prioritised and agreed.Several iterations may be req uired before agreement can be reached, and it will certainly be necessary for a number of possibilities to be canvassed before the detailed statement of the problem which emerges from the process can be finalised. Returning to the short-term shelter ex ercise, one team might decide that speed was all important and decide to take along a large amount of sheet plastic in which to wrap themselves, while another might reconnoitre and discover a cave and trees from which a rude shelter could readily be constructed.A third might decide to remain on the boat in the short term. Members of one such team would not agree with the priorities of another, but each would have solved the problem as they themselves defined it. Designers are not usually their own client, and so it is essential that the client’s priorities are clearly understood and followed. It should be appreciated that, even if there is a single designer, or a very small team, this analysis should be carried out carefully –and that it can be harder to evaluate the accuracy of the understanding where there is no team of minds to consider what is proposed.

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Synthesis The stage is now reached where potential solutions can be proposed. It is necessary to understand and give due weight to the many aspects of the problem.Figure 9.3 summarises the headings under which they will come –and it is important that each of these three main categories should be addressed, if the design solution is to be balanced.The diagram in Figure 9.3 develops the sense of the need to balance efficiency with pleasure and practicality, articulated by Sir Henry Wotton (1568–1639): ‘In Architecture, as in other Operative Arts, the end must direct the Operation.The end is to build well.Well building hath three conditions, Commodity, Firmness and Delight.’

The Elements of Architecture Each of these aspects is likely to be addressed independently, but it is their interaction which is necessary for success. There will always be a number of potential solutions –if designers can visualise only one, they are blinkered and it is necessary to find a way of generating more.Techniq ues through which this can be achieved include:

• •

9.3

accurate reporting –using objective, not subjective language; parallel thinking –looking for as many synonyms for terms as possible;

C R E AT I V E P R O B L E M - S O LV I N G

• • • •

lateral thinking –making the effort to escape from the tram tracks of habit; brainstorming –collecting many unex amined ideas from a group of people and only later eliminating those that do not measure up to necessary criteria; extreme thinking –believing the inconceivable;and the Eureka moment –allowing the mind to wander and make unex pected conjunctions.

These are ex plored further in the nex t chapter. It is only when a design team has at least three potential design solutions before it, that it is possible to proceed to the nex t stage of the process.

Development Designers usually have ideas teeming through their heads almost as soon as they hear of a project, and it is vital that these should be disciplined. More and more will be generated as the team interact. It is, therefore, essential that a formal structure of evaluation is set in place, since otherwise undue significance may be given to some splendid but entirely impractical notion.The best way in which this is achieved is usually by the team as a whole ranking alternatives by the light of the conditions set in the brief.The client should only be approached with a solution in which the team as a whole has total confidence.

Communication It now becomes important to convey the outcome of the process to the clients for their approval.The team will wish to make it clear that suggestions are not made arbitrarily, but it is not necessary to detail the thought processes which lie behind the scheme though the team should be ready to ex plain the reasons for the proposals they are making.

During construction The responsibility for design does not cease when the client approves the proposals. It will be readily understood that it continues through the preparation of contract documentation, to ensure that the vision is not lost. It is not always appreciated, however, that it continues throughout construction.This is the case for two reasons:

•

to ensure that not only the constructional but also the design aspects of the project are carried out correctly;and

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•

to respond to contingencies arising during construction and ensure that they are resolved in accordance with the original intentions.

Summary It is important to stress that design:

•

is

•

is not

–systematic; –realistic; –creative; –evolutionary;and –arbitrary; –imitative; –fashionable.

Chapter 10

The problem Developing the commission into a brief As pointed out in the previous Part, though the client presents what he or she understands to be a job to be done, in the form of his or her commission, it is not possible to begin meaningful workuntil this commission information is ex panded into the brief. Figure 10.1 gives a frameworkwithin which the whole process may be controlled.The most important stages are those marked ‘Thinks.’ The collection of the information req uired will be performed in a number of ways, and it is important to recognise what material is useful and relevant so that the process is controlled appropriately. Making sure that everything significant has been discovered will be time consuming, and it is necessary to allow sufficient time for this essential first stage of design.It may be most satisfactory to deal with the separate areas under the headings used in referring to the content of the commission (see Chapter 6).

F u n c t i o n a l re q u i re m e n t s The ways in which the accommodation is to be used can conveniently be defined in detail by the use of the Briefing Chart, which is discussed in Part 4, Chapter 16, along with other sources of information about the arrangement of space.As discussed there, it is the client’s responsibility to state how he or she intends and ex pects the building to be used, but not what accommodation is req uired to house those activities. Freq uently, if an ex isting activity is being provided with new accommodation, it is found that it is currently being carried out in less than optimum ways, enforced by its present unsatisfactory spaces.This

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10.1

THE PROBLEM

95

may make a detailed study of best practice, as found in other ex amples of similar buildings, desirable. The only usual ex ception to this rule that only the activities direct the method by which they are best accommodated would be, in the case of an ex tension or adaptation to ex isting property, where a need to respect what already ex isted might intervene.

It is freq u ently the case that clients, especially inex p erienced ones, present with what they feel is a fully developed plan of the building they want, which they ju st hope someone will arrange to build for them. It is necessary to make it clear to them that to get the best possible building for their purpose on their site and within their stated limitations, they should trust their professional advisers to use their skills to produce the optimum solution. Such people are trained, and are being paid, to perceive how best to use the available resources to solve the given problem. Helping the client to differentiate between what is wanted and what is needed often calls for considerable diplomacy. It is occasionally necessary to do some development workon the lines the client has in mind, so that the strengths and weakn esses of different solutions can be fully demonstrated, but it is best if this can be avoided as it is wasteful of resources.

When the details of the client’s needs have been established, it should be regarded as a priority that they are to be met.If at any time it seems possible that they may need to be compromised, this must be fully discussed with the client and their instructions obtained. Probably the commonest situation where this may arise is the case of the cost limits appearing inadeq uate for the whole of the brief to be met.

Cost limits The duty of staying within the client’s cost limits has often, notoriously, been disregarded.This is irresponsible, and should never occur. An early discussion is necessary, during which the realism of the client’s ex pectations is ex amined, but once a cost limit has been set a mechanism to ensure that it is not violated should be put in place. Within this, it must be clear what portion of the total ex penditure is accounted for by the design process and other overheads.A percentage set aside for unforeseen contingencies –additional to the ‘contingency sum’ included in the contract documents –should also be allocated.The total sum available as an anticipated contract figure should then be apparent.

Cost planning, based on analyses of earlier projects, is a helpful tool for ensuring that this sum is not ex ceeded.

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In this techniq u e, cost breakd owns of earlier, comparable proje cts are ex a mined, to ex t ract the percentage cost of specific elements, such as structure, finishes and so on.These are often broke n down in some detail. In this way, for exa mple, under ‘s ervices’ the proportion of the cost attributable to heating, artificial lighting, communications and so on are separately indicated. Within communications the sums for telephone, intranet and broadband would be indicated individually if they could be obtained. It is important that an allowance is made for contingencies. Analyses of a number of buildings should be obtained, so that the unusual circumstances of a particular proje ct do not distort the picture. A typical set of figures can then be calculated.The percentages derived can then be applied to the global cost allowance for the new proje ct, showing actual ceiling costs for similar elements. During the development of the design, regular checks will be made on the cost implications of decisions, and it will often be found that adju stments have to be made.The only responsible reaction, if it is found that one element is going over budget, is to find eq u ivalent savings elsewhere.

10.2

Cost analysis and planning are ex amined in detail in Volume 4, Practice, Management and Responsibility.

Terotechnological assessment is also of great value.This is a method of establishing the lifetime costs of a building (or any other capital investment).It is necessary to begin from an assessment of the economic life of the building, and to calculate the whole costs, set against any residual value. This techniq ue will be dealt with in detail in the Volume 4, Practice, Management and Responsibility, in this series.The importance of this aspect of design implies that the Quantity Surveyor should be a full member of the team in the case of any sizeable project.

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The costs of actually setting up the building, including fees, the time out of use, the construction costs, and running and maintenance costs throughout the building’s life are calculated.These are set against the value of the building when it is sold off as no longer suitable for its original purpose.Often it can be demonstrated that additional first cost will pay for itself over considerably less time than the life of the object purchased. For ex ample, roof insulation is often said to pay for itself in three years in terms of saved energy, while it will continue to be effective for the life of the building. Similarly, if good carpet costs twice as much as a cheap floor covering, but lasts three times as long, it is a good investment.

Ti m e l i m i t s The relationship between costs and time spent on the project, both in design and construction phases (see Chapter 6), should also be discussed with clients, and an agreed timeframe be established.This will indicate the essential dates for briefing to be complete, when a design will be presented and agreed, the completion of contract documentation, the invitation of tenders, and the construction begin and end. If these latter two dates are important to the client, they will become design contract conditions. All members of the design team should have an opportunity to comment upon this programme before it is finalised.They must ensure that adeq uate time for proper analysis of the need and investigation of the options is allowed, and that it will be possible to complete contract documentation before tenders are invited.If this will not be the case, they must draw the attention of the client to the fact that cost control becomes that much more difficult. Once a programme is agreed, the design team must understand and adhere to it. It will no doubt be developed in more detail at an early team meeting.

The site Essential information regarding the nature of the site comes under a number of headings, and will be obtained from a variety of sources.

Aspect and prospect It is important that the lead designers visit the site, or at least obtain a comprehensive photographic record of it, in order to understand its characteristics and the nature of the surroundings.The materials and style prevalent in the area are essential parts of the environment of the building to be designed which should never be overlooked. There may be views to be ex ploited, others to be screened.A nearby motorway may give ex cellent access but create a noise problem, and

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10.3

10.4

THE PROBLEM

so on.The degree of ex p osure to the elements, including potential solar gain, can best be assessed by a personal visit.While the presence of ex isting structures, trees and other features will be noted in the survey, it is impossible to determine which of these are best removed and which worth preservation without a personal visit.

Ownership It is vital to establish the nature of any restrictions limiting the title to the land, which may constrain the ways in which the site may be used. The commonest of these are the following:

•

Easements, which are enduring req uirements, such as the right of way or the right of light, by which the owner of one property can limit the uses made of adjoining land in other ownership.They generally come into effect either by grant or as a result of being enjoyed unchallenged for a period (technically from time immemorial, but in practice q uite short periods, see panel below). Easements are common law rights, almost always established by long use, and are very difficult to ex tinguish other than by the adjoining sites coming into common ownership. Developers

Easements A right of way comes into ex i stence if the public has had unrestricted access to a path or to land for a lengthy period, or if an adjo ining owner has either been granted or has used a path as access to his own land for 2 0 years or more. It can have severely limiting effects on the use that can be made of the affected site, since privacy and security may be compromised. A public right of way cannot, by its nature, be ex t inguished by the means mentioned above. i sting opening, which has been there for 2 7 years or more. (A blankwall A right of light is enjo yed by an ex does not enjo y such a right, so a new window made in an ex i sting wall will not acq u ire the right until the statutory period ex p ires after its construction.) Such an opening must not be obstructed by building on the adjo ining site. It is possible to serve notice of the intention to develop before actual building starts, so as to prevent the opening in q u estion from acq u iring the right. The most common relevance of this right in relation to new building is that windows in adjo ining, ex i sting properties need to be considered throughout the design process, since they must not be obstructed.This can, of course, be significant to the siting of a new building.There is normally no common law right to a view or to air.

Right to support from an adja cent building may exist where a property has been part of a terrace, so that it relies on a party wall. If such a wall is exp osed during redevelopment, it may be necessary to provide a new wall to ex t ernal standards to replace it. A building also acq u ires a right to support from the ground around foundations, so that if nearby ex c avations will undermine this, suitable remedial action must be take n by those making the ex c avations.

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•

sometimes purchase property adjoining that to be developed purely in order to ex tinguish such rights. Covenants are specific restrictions on the use of a site included in the terms of transfer of the property.They may, for ex ample, prohibit activities such as brewing, or noisy activities at night such as might be created by a night club in a residential area.There are often covenants attached to previous church buildings, restricting the uses to which they can be put, so as to avoid activities that the worshippers might have found repugnant, such as gambling. Covenants are common where properties in whole districts are, or were, held on leasehold tenure.Like easements, they are hard to remove.

In any case where the ex istence of an easement is suspected, or that of a covenant known, designers should askthe owner to obtain legal advice.Designers should not rely on their own knowledge or ex perience in such matters.

Legal restrictions The req uirements of the planning authority, including any regarding:

• • • •

conservation areas; national parks; restrictions due to the prox imity of air corridors;and other limiting factors,

have to be canvassed as part of the briefing process, since they can have a significant effect on what is possible. Enq uiries of the planning authority should also include req uests for information regarding proposals under discussion, for the area, for road or rail building and the development of other properties. Similarly, if the development is to take place in an unfamiliar district (s uch as another country) the req u irements of any building codes must be assimilated.While these can be ex p ected to share the preoccupations of those of one’s own country, they will be worked out differently in detail. It may be essential to obtain an authoritative translation.

Physical nature of the site Much abortive workcan be avoided if the actual land is fully investigated at an early stage:

•

The survey will provide detailed information, and should include:

–

the location in relation to the surroundings, including adjoining property, roads, rivers and rail;

THE PROBLEM

• •

— levels in relation to Ordnance datum –where there are appreciable changes of level, contours, spot levels and sections are helpful;and — the dimensions of the site. The plan should be to a large enough scale to be used as the basis for a design and a construction site plan. The site investigation should give data on: — the nature of the subsoil, including its bearing capacity;and — the water table. Enq uiries of the relevant service providers give information on the position, levels, accessibility and capacity of services, including: — sewerage; — water; — electricity; — gas; — telephone;and — cable.

The brief Any part of this detailed material may affect the viability of the site or of particular options that could be considered for the design solution. If detail surfaces after workon the design has begun it can, in ex treme cases, mean that the developing workhas to be unwound to the point where what have proved to be inaccurate assumptions of that particular aspect of the conditions were relied on. The brief, then, is a considerable document, and since it will form the basis for all further work, all the information must be collected and recorded in a coherent and accessible form.It will include:

• • • • • • • •

the briefing chart or a similar record of detailed req uirements; the cost plan of target costs within the overall max imum cost; the programme of agreed dates; ownership information regarding the site; legal restrictions on the development; the survey; the site investigation;and the outcomes of all the discussions between the team.

It is essential that the whole of this material, having been established as a viable frameworkfor progress, should be agreed with the client. The client must understand that all future workwill be based on the conditions laid down in the brief, and not on any that are omitted from it.

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If at any point a previously unrecorded condition is brought up, this may well undermine a great deal of completed work, and, because it is necessary to unwind progress to the point where the item was crucial, additional design time and therefore delay and additional fees will become applicable.

Evolving a design The team of specialists, or the sole designer in the case of a simple problem, now has a wealth of information which constitute the problem to be solved and must hold the solution within it. It is important that members of a team should workin a spirit of mutual co-operation, so that a single coherent design eventually emerges.The elements of group dynamics were referred to in Chapter 5.At a first meeting, it would be usual for two important sets of guidelines to be agreed:

•

•

10.5

The hierarchy of decisions should be established, so that it is known at what point, for ex ample, the siting of the building, the structural system to be adopted, the heating system and so on will be known.In different cases, the detailed planning of accommodation, the choice of structural system or the architectural style might be critical, and therefore given priority. The critical dates will be set, so that, within the programme agreed with the client, each degree of completion will be reached. It is important, for ex ample, that the availability of the detailed cost plan should be known before materials are proposed, that the

THE PROBLEM

10.6

10.7

10.8

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structural engineer should know when the service runs to be accommodated will be established, and so on, if abortive workis to be avoided. At the same time, dates for formal meetings to which all will report will be agreed. It then becomes possible for the team to disperse, so that each member can progress their own elements of the design, relying on informal contacts.Later chapters deal with the specifics of many of these particular areas, but within the mathematical or other parameters of each case, each specialist will be anx ious to find the optimum answer to the discrete problem.Though most minds will run naturally to t‘ ried and tested’ solutions, they can be more certain of success if they aim for innovative think ing.Some methods by which this can be achieved include:

•

• •

Accurate reporting. There is a story, possibly apocryphal, of a lecturer who walked into a room in which there was a group of students and a table covered with a cloth.As he approached the table, it began to move towards the windows.He sat, and asked the class to write down what had happened.When he collected their papers, he found that one had written that someone under the table had raised his backand crawled towards the window, one that the lecturer had pulled a string, one that a passing aircraft had caused an up-draught, which had sucked the table outwards –and so on and so on.They had tried to interpret their observations, not to report them objectively.(One student alone gave an objective statement as in the first two sentences above. She was the only one to get a good mark.) Always aim for the most objective statement of the client’s needs. State the limits of acceptable conditions of temperature and humidity, which is the problem, rather than mention air-conditioning, which is a solution. Parallel thinking. Put it in different words. Do not say ‘chair’, say ‘stool’or ‘misericord’, which are alternative solutions to the same problem –or simply ‘somewhere to sit’. Lateral thinking. Edward De Bono suggests that lateral thinking has four important elements: — looking at the usual solution, and recognising its limits; — looking from a different perspective; — relax ation of the rigid control of thinking;and — playing games to encourage other ideas. For ex ample, you can put unusual conditions into an ex ercise – limit the materials or the time in which it has to be solved.This will nudge the brain out of one-trackthinking. There is one ex ercise in which students are given straws to represent scaffold poles and pins to represent pin joints, and told there is an injured agent with a great secret who must be got out of an enemy camp, which is surrounded by an electrified fence within a piranha-infested moat (dimensions are given).They have

THE PROBLEM

•

•

•

to get the agent out of the compound.Most of them devote their time to constructing elaborate crane-like structures to reach into the compound.The lateral thinking solution is to pitch the poles at the fence so as to electrify the water and kill the piranha, so the rescuers can swim across to bring the captive to freedom. Brainstorming. A group of people, thinking very rapidly, propose ideas without any critical thought at all.All ideas are recorded.It is only at the end of an agreed period that the list is reviewed critically, those ideas that are clearly impractical are discarded, and the rest are ex amined to see which are viable. Extreme thinking. Askthe q uestions ‘What? ,’ ‘Why? ,’ ‘How? .’The veteran politician Tony Benn is recorded as saying on BBC television in 2 0 04 that ‘The limits of possibility are not the limits of what has been done’.Thinkabout this. The eureka moment. Richard Wiseman tells us that we see what we ex pect to see.The e‘ ureka moment’hits us when we manage to see the unex pected. It is useful (and fun)to read his book Did you spot the Gorilla?.

Such techniq ues should result in a set of possible solutions to be tested against the whole of the data.Each specialist will be able to ranktheir possibles in terms of desirability from their particular point of view. However, only the group can determine which should be selected because the entire set of specialist material has to be formulated into a single whole. When three probable global ideas are available for consideration, a process of rigorous testing should be begun. Still open to a number of possibilities at every stage, the team is now in a position to develop the potential ideas into actual design solutions.Each of these must be subject to rigorous ex amination against the criteria inherent in the brief, so that the optimum solution emerges. There will usually be a number of iterations of this process, as possible improvements are recognised and adopted.As the team members will, to some ex tent, be work ing independently and meeting only at intervals, there will be inevitable debate, often leading to a need to compromise, a wish to return to first principles –and often to innovative think ing. However, there are limits on the time which can be afforded for the process, and a strict schedule and deadlines will have been established.The solution which has to be proposed and agreed will not be the ultimate, but the best that can be achieved within the limitations of the project’s time and cost budgets.It now has to be put forward for the client’s consideration.

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Communication When conveying the proposed design to the client it is important to bear two points in mind:

•

•

The client must be given an accurate idea of the intentions.They need to know the nature of their intended investment, and it is highly undesirable that the client should ever be able to feel that they were misled, even if the misunderstanding arises from the client’s own inability to appreciate the nature of the proposals. Every care must be taken to discuss the proposals with the client, to answer their q uestions fully and to obtain their appreciative agreement. Means of communication which are familiar to the people who are to understand them should always be adopted. It is inappropriate to resort to starkly technical drawings and language in this contex t.Please read Chapter 7, Communication, with this in mind.

If the briefing was thorough, and the client was helped to make their needs known (as well as any prejudices), it should be ex pected that the client will be delighted with the scheme with which he or she is presented.Should this not be the case, a further iteration will be necessary, with the effects on time and cost which have been discussed before.

C o n t ra c t d o c u m e n t s The preparation of the drawings and specification, against which either a Bill of Quantities or a tender can be obtained, must always be regarded as an integral part of the design, since many detailed aspects are dealt with here.This is not a taskwhich can be handed to someone who was not a party to the decisions taken, but must at least be supervised by the specialists directly involved in the evolution of the design solution, who can ensure that compatible decisions are taken. The nature of these documents is discussed in Chapter 7, and are developed in detail in Volume 3, Materials, Specification and Detailing.

Chapter 11

The process in action

The case studies in this chapter are fictitious, though they call upon ex perience of many real cases. Nothing in the scenarios should be taken as comment on actual people or events.They are considerably simplified, and are intended only to ex plain the process outlined in Chapter 10.They do not address in detail the spatial, aesthetic and technological aspects of the process discussed later in the book.

Case study 1 – Instant shelter A class of first-year students was set a weekend task.They were divided into groups of five, and each group was given £ 10 by a benefactor.They were taken to a paddockin the grounds of an out-of-town property belonging to their university. It was the just before the end of the second term.They were not given advance notice of the reason for their trip, though they were warned that they would be away over night and should bring sandwiches. When they arrived, they were told that, using found materials, and spending no more than the money they had been given, they were to construct a shelter in which the group would spend the night.Toilets and cold water were available at the nearby stables. One group set off at once to forage for materials, while others began by staking out the most sheltered sites near to the water and drainage points.Yet others sat down to consider their options, and to assess what resources they already had available. (One of these groups decided to spend their money on chips, wrap up in the sleeping bags they had providentially brought, and see the night out.)

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The scavengers discovered a skip full of demolition materials behind the stables, and were able to use pieces of ancient fencing to create a windbreakagainst a tumbledown wall.Over this structure they draped a rather precarious sheet of plastic. The more thoughtful groups divided their resources, having decided what they needed to find.One set felt sure there would be materials to hand, which they were allowed to use, or they would not have been brought.Taking hay bales (which they found in the stables)they built three walls a metre and a half high against the boundary, and by venturing into the village they were able to find a couple of old doors that were being thrown away, and pay a local woman to drive them up in her van.From these materials they were able to construct a warm and serviceable shed.The farmer insisted in the morning that the bales be returned, and was not impressed to find them saturated. The other group considered what they already had, which included three q uilted jackets and four sleeping bags, all shower proof.They bought duct tape in the village, with which they fix ed these together, hanging them over dry branches which they brought from the woodland around.They spread a single plastic sheet on the ground.This group found enough dry wood to start a fire at the opening to their shelter, and agreed a rota so that there would always be two people awake to keep an eye on the fire. All of these groups considered the need for basic shelter, one thought this was unnecessary in the short term (they got rather wet but came to no harm).One group annoyed the neighbouring farmer but created a shelter that would have served for longer than a single night, and one spent a comfortable night. The students had not been warned that the press would turn up in the morning, but were pleased with their warm write-up, in spite of the dishevelled photograph that was printed.They agreed that practice had taught them more about shelter than theory ever could.

Case study 2 – A private house The client, Bob Robson, was a widowed man in his early six ties, who approached a local architectural technologist, Chas Phillips, whom he knew through the golf club, with a view to building a house in which he could ex pect to spend his retirement.

Stage 1 – Defining the problem Bob had the family home to sell, and felt that he needed to put as much as possible of the capital aside to provide an income to supplement his pension.His priorities were:

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• • • •

a home he would be able to remain in independently, even if he became disabled as he grew older; space for his grand piano; low maintenance req uirements, both in terms of regular housekeeping and refurbishment;and energy efficiency.

Working with Chas, he completed the briefing chart shown in Figure 11.1 (see Chapter 16 for detail on the use of such charts).After many months of searching, he had found a site which was part of someone’s garden in an early Victorian suburb, near to where he lived at present (Figure 11.2 ).The road frontage was to a small cul-de-sac among conventional post-war semi-detached houses.

JOB NO ABC Activity

BRIEFING CHART House in Brindlewood Arrangement share next with to

Shape

Features

near to

level

aspect

size

bath

GF

road

4 people

Sit

eat outdoor bath music sit

GF

SE/SW

Eat

sit

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sit

GF

Cook

laundry outdoor sit

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sit cook sleep

cook

equipment

light

Remarks

hum- temp- power floor wall idity erature surface surface Í

soft

Í

piano

Í wash wash

extraction wash

GF bath

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1 person

soft wash

access sleep

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4 people

shelter 11.1

11.2

extraction

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THE DESIGN PROCESS

Stage 2 – Analysis As Chas had not been authorised to employ consultants, he had to find alternative ways of collecting the data he needed. He immediately made an outline planning application, to confirm that permission would be given for a dwelling on the site, warning Bob not to finalise the purchase until this came through. He found maps in the archive section of the local library, which showed the earlier layout of the site, and the local authority (LA)drainage plans provided manhole invert and cover levels, which were accessible and did not create problems.He knew, from workhe had done in the vicinity while he was employed by a local surveyor, what the subsoil would probably be like.

Outdoor sit Cook Laundry

Sit Music

Eat Bath

Access

11.3

Sleep

He produced alternative cost budgets by reference to published cost analyses of comparable houses, supported by estimates of the related running costs in each case.The first of these was for a conventionally constructed house, while the second allowed for enhanced standards of thermal insulation and for high-q uality, low-maintenance materials. There was a premium of 30% for the second case, but he calculated that the difference would be paid for in reduced running costs in the first 10 years.He made a generous allowance for inflation, and arrived at a cost per metre he could apply to both the alternative designs he intended to workup.He relied on his own understanding of services and structures, though he n k ew he might need to get specialist help later. On the basis of the briefing chart, he prepared a circulation diagram on the lines of those discussed in detail in Chapter 18, which he discussed and agreed with Bob.

Stage 3 – Synthesis Chas now had three points he felt that he needed to resolve:

•

• •

11.4

as achieving low maintenance costs and good energy conservation might involve higher capital ex penditure, he felt it important to make a realistic lifecycle cost assessment, so that Bob could understand where additional outlay would reduce year-on-year ex penditure; he was concerned that the new house should fit into its environment, which included Victorian properties to one side of the site and twentieth century ones to the other;and he was unsure what degree of internal privacy Bob req uired in his home.

He therefore sketched out a number of possible arrangements of the floor plan (taking care that the major pieces of furniture, and especially the piano, were located), and selected two as potential solutions to the spatial problem.In each case, he included a service core, so as to minimise


service runs.He sent these sketches to Bob, along with his considered advice that spending money on a high specification would be costeffective in the long run, with calculations to support this. Having had a discussion with the planning officer, he was able to advise that a simple modern brickstructure would be acceptable to the LA, so long as the materials sat well with those of surrounding buildings, and he advised that the proportions of openings and so on should follow the precedent of the Victorian villas. Chas and Bob met at the site, so that Chas could point out what the views from the windows would be, and the degree of overlooking he might encounter.They also spoke at length about the advantages of spending money in the short term to save in the long term.

11.5

It was noted that while the L-shaped plan provided a sheltered outside living space, and allowed for windows in the kitchen and bathroom areas, the perimeter was significantly greater than in the alternative. Chas advised that it would be more economical, in both the short and long term, to have as compact a plan as possible.Bob said that, so long as his outside space was not overlooked he was happy for it to be screened by shrubs.He did not thinka bathroom window was important, so long as there was ventilation, and he rather favoured an open plan living area, where a kitchen window would not be missed. On the basis of this discussion, Chas undertookto produce a revised design, allowing for enhanced privacy from outside, but tak ing out several of the physical internal divisions. A high specification would be included. Bob made the point that he was not concerned with the eventual resale value of the property, as he wanted a home where he could stay for life. He agreed that features which would make adaptation to disabled use, such as wide doorways, level access and waist-high electric outlets, should be incorporated, even though they might lookunconventional, and could affect resale.

Stage 4 – Development A revised floor plan was now made and some critical details, such as that of the ex ternal walls with their enhanced insulation, sketched. Specification notes were written, to include triple glazing, high-q uality finishes and so on, and, with Bob’s agreement, a q uantity surveyor was invited to give an estimate of cost.This turned out, to Chas’s relief, to be comparable to the figures he had floated earlier. The plans allowed for an efficient condensing boiler, and a horizontal duct was shown, built into the ex ternal walls 900 m above floor level, to carry the power circuit, with double switch 13 amp points every 1,000 mm along it, so that trailing leads could be avoided.

11.6

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THE DESIGN PROCESS

Stage 5 – Communication

11.7

Chas used a fairly basic CAD programme to set up the plan, so that a simple perspective (sketched here)could be generated to give Bob a sense of what the building would feel like.The plan and estimate were agreed, and tenders were invited on the basis of drawings and a q uite detailed specification.The lowest tender came in just under the estimate, and was accepted, and the house was completed within four months.

Case study 3 – A teaching block Three technical colleges came together to form a new independently funded college of technology, within which the Department of Construction was to be a core.The various institutions which made up the new college had offered courses for building and engineering technicians to HNC level, and for craftspeople as well as in building management, landscape and interior design.All of these were consolidated in a single department, which it was intended would develop a degree programme in design and construction technology.A new blockwas req uired to house the necessary facilities, and a sloping site on the outof-town campus was found (Figure 11.8).

11.8


The college’s Buildings Division would be the commissioning authority, but an advisory committee representing also the staff of the Department would be set up to monitor the project.A major multi-disciplinary design firm, Technical Building T ( B), was offered the commission. It was a req uirement that the facilities should be capable of straightforward modification as new curriculum needs and technology developed.Completion was needed within two years from commissioning. The finance available was strictly limited, by the industry-based funding authority, to a total cost per sq uare metre common to laboratory based departments in universities.For this reason it was essential that as many as possible of the laboratories and workshops should be multi-use.

Stage 1 – Defining the problem Each of the three departments which had formed the group had its own strong ethos and a determination not to be dominated by the other two.Each had had accommodation which had evolved over a number of years, and which, though admittedly outmoded, was familiar to staff. It seemed to the consultants that, rather than teaching patterns determining the facilities, the facilities had at least to some ex tent been dictated by the content and style of teaching. The college arranged an off-site ‘bonding’weekend for the staffs, and invited TB to send representatives, and to take the opportunity of describing the design process which would be followed in mak ing plans for the new building, as well as the constraints which would apply.TB made clear that compromises would be req uired from everyone.The use of a briefing chart was ex plained, and it was agreed that each course team should complete a chart independently.They were also asked to indicate the anticipated usage in hours per weekof each space. In spite of their familiarity with the industry, the staff appeared to be u qite surprised that they were being asked to define a problem, because they already thought they n k ew precisely what accommodation they needed. Health and safety, and fire resistance and escape issues were investigated. As the department would not be entirely self-contained, but would rely on service teaching for certain subjects (such as law), it would be necessary to consider the relationship of the blockto the rest of the campus.

Stage 2 – Analysis TB began their analysis by a study of the competing charts produced by the course teams.They were able to see that there was much less conflict between the req uirements than might have been anticipated. They found it possible to consolidate the practical req uirements into

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THE DESIGN PROCESS

a single chart, where the incorporation of a limited number of additional facilities would facilitate the provision of multi-purpose spaces that could be in use for a significant part of the teaching week. It was anticipated that, in total, there would be 350 students in 15 cohorts, 10 research students and 0 2 full-time teaching staff, as well as 10 technicians and 3 administrative staff.Accommodation needs were resolved as:

• • • • • • • • •

4 laboratories, each with prep room; 2workshops, each with prep room; 2lecture theatres; 4 studios; 4 seminar rooms; 2 0 staff rooms; 1 administrative office; 1 common room;and appropriate cloakrooms and toilets.

No library provision was needed, as this was centralised elsewhere on the campus.Computer points would be available in every room. The mechanical engineers considered the service req uirements of the spaces.They formed the opinion that, to allow for possible future changes, ex tensive accessible ducting would be needed to permit service outlets to be provided at virtually any point in the laboratories, work shops and studios.They considered this to be a priority, and produced sketches to show the cross-sectional area that would be req uired.They were inclined to recommend a vertical stackserving labs on each floor. Meanwhile the structural engineers commissioned a full site investigation to determine the nature of the subsoil. On the basis of this, and of the big change in levels shown by the site survey, they recommended that a max imum two-storey building should be preferred, with the ground floor level stepped to follow the contours. The q uantity surveyors produced a detailed cost plan.From this it was clear that there was a choice between providing high-q uality finishes throughout, providing the full range of spaces indicated or of providing the sophisticated eq uipment considered necessary. The site was situated at the focal point of two approaches to the campus, and the building, in the architects’opinion, needed to make a firm statement.This would also serve aesthetically to ex press the importance ascribed to the department within the college. When these preliminary investigations were complete, the design team met to consider priorities.They tookinto account that basic seminar rooms and staff rooms could be made available elsewhere on the campus. So far as practical considerations were concerned, it was concluded that the priority should be given, in order, to:


• •

• • • •

health and safety req uirements; the provision and eq uipment of specialised teaching spaces, to the highest necessary specification.These should not be compromised for the sake of centralising the whole of the department’s accommodation in the one block; toilet and cloakroom provision; staff rooms; lecture theatres;and seminar rooms.

Taking into account the advice of both the mechanical and the structural engineers, it was decided to develop two sketch plans, one concentrating on a tower blockas recommended by the mechanical engineers, and the other following the contours as the structural engineers suggested, so that the two could be evaluated.

Stage 3 – Synthesis Plans on the lines of the sketches shown were produced by two different architect members of the team. On the basis of these, outline proposals for the structure and for the distribution of services were offered. The first of the proposals shows a triangular six -storey blockwith two major teaching areas and one studio and one seminar room on each of the four floors, with ground floor service and plant areas and staff rooms and common room on the six th floor.There is a roof terrace.The blockis served by two passenger lifts and one service lift, and the central service duct feeds a shallow, accessible duct space between floors and ceilings. The building is intended to be simple but striking in form, and to have a minimal ex ternal envelope, so limiting cost while providing high standards of insulation. The reinforced-concrete structure would incorporate lattice beams, so as to allow easy distribution of services.

11.9

In the alternative plan, a two-storey core containing the administrative and staff accommodation is proposed, with four single-storey wings for the teaching spaces.The plant and service areas are in a basement to the central core, and services are distributed through ducts over the corridor ceilings.Strong sculptural forms reflecting the nature of the accommodation would ex press the function of the building ex ternally.The frame is intended to be of lightweight steel, and there are no lifts.

11.10

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THE DESIGN PROCESS

Stage 4 – Development Though the authors of both proposals were vocal in their advocacy, neither of these plans was considered satisfactory.However, they were rigorously evaluated and provided a fruitful basis for discussion. The six -storey design was admired for the compactness of the service layout and for its potentially striking appearance.The reliance on lifts was considered unfortunate, but it was believed that the relationship between the spaces would be convenient and that a congenial environment for learning would be produced.One disadvantage might be that students (though not staffs)of different disciplines were somewhat segregated. The low-rise solution was liked for its simplicity, and for the fact that everyone would use the central core and so mix .However, it was calculated that it would be less economical in running costs. Disabled access presented a problem because ramps or stair lifts would be needed at each change of level.The thumbnail sketches which accompanied the plans seemed to offer the potential of an innovative building (suitably ex pressive of the disciplines accommodated), but this would need careful integration into the ambience of the campus. From these discussions, a consensus emerged that the final scheme should incorporate the following features:

• • •

the laboratory spaces should be clustered around a compact service supply; there should be no changes of level other than ones accessible by lift;and the building should be immediately recognisable as a centre of ex cellence in building design and construction.

An innovative scheme was now developed, in which there were two large open plan laboratory spaces, one with the workshop type facilities and one conventional.The studios and seminar rooms would be clustered around these, while the lecture theatres should be shared with other departments.Staff rooms would remain individual, for the sake of privacy in interaction with students, but would be small and basic.This suggestion was put to the advisory committee, who indicated (after some discussion)that they would be prepared to consider a design on those lines.A new, more developed plan was made (Figure 11.11)and rigorously ex amined.After a number of modifications, the design was approved within the design team.

Stage 5 – Communication A sketch model was made to discuss with the advisory committee, supported by carefully prepared estimates of cost and of the time-scale of implementation.The cost estimate was 15%above the limit set


Staff Seminar

Seminar

Studio

Shop

Studio

Laboratory

Laboratory/ workshop

Cafeteria Studio

Studio

Seminar

Seminar

Staff

Shop Staff

11.11

down, but TB were able to show that this difference would be made up by savings when modifications to the building were inevitably needed.TB reported in detail on the reasons for the proposals made, and advised their acceptance. These materials were formally evaluated by the committee against their req uirements as originally formulated. It was agreed that they could only be accepted subject to modification in the overall development plan for the campus to incorporate a new central lecture and seminar block.Since it was unclear where funding for this would be found, there seemed to the committee to be only two courses of action available:

•

to have new plans prepared to include the whole scale of accommodation req uired but to a lower initial specification, in the hope that upgrading might be possible once funding became available; and

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THE DESIGN PROCESS

•

to rethinkthe departmental teaching timetable so as to obtain increased use of a smaller range of rooms.This could be achieved either by lengthening the teaching weekor by shortening vacations.Since neither of these strategies was likely to be acceptable to the unions involved, this option was discarded.

The professional fees spent to date were therefore written off, and TB were asked to prepare new plans against an amended list of req uirements. In particular, the need for the ease of alteration to the use of rooms, and therefore for the ex tensive accessible ductwork,was abandoned.The original two-year programme for completion had already been overrun. New plans were prepared, and a simple but workmanlike building was erected, to meet the immediate needs of the department (which had changed somewhat during the intervening period), coming into use four and a half years late.After 10 years this proved to be obsolescent, and a new building had to be commissioned.TB were offered the commission, but declined.They were concerned that the institutional inability to understand the benefits of long-term cost planning or to think laterally (based on a rigid organisational structure) reduced the chances of producing fully satisfactory outcomes. This case study is believed to be instructive, and to repay consideration.The unfortunate outcome of the design cycle might be laid at a number of doors, and there will be various opinions as to where the faults lie.

Chapter 12

Aesthetics I n t ro d u c t i o n It is q uite commonplace to accept without q uestion that the space in a building, and the way in which it is arranged, as well as the characteristics of the envelope which surrounds that space, can only be finalised after a process of analysis of need and the application of scientific knowledge.Objective standards are naturally evoked as a basis for such decisions. The ways in which the spaces are to be used have to be established, the optimum conditions for their use determined, and structural elements chosen which are not only durable and safe but also conducive to providing those conditions. It is not always so freely accepted that producing a building that will be visually pleasing is an eq ually objective undertak ing.Aesthetics is both a branch of philosophy concerned with u qestions of taste and beauty, and also of consideration of the rules governing art.It encompasses music and poetry as well as visual u qestions, but it is these last with which designers usually need to be concerned.For reasons that would have to be referred to the philosophers, the ex istence of rules of harmony and rhythm in music, of metre and rhyme in poetry, is more readily accepted than the suggestion that visual design is also subject to guiding principles. There is also sometimes confusion between art and design.One of the distinctions between these is that fine artists set out to make personal statements.They do not seekto please an audience or to provide decorative objects, but to ex plore their understanding of space and their perception of the human condition, and to present the outcome for consideration by others.This is the area in which aesthetics is considered as a philosophical discipline.In comparison, the designer sets out to solve a practical problem in an aesthetically pleasing way.

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The distinction between the artist and designer in the visual sphere can be thought of as parallel to that between the novelist and the journalist where the writing of prose in concerned.Both produce honest work and make useful contributions to society, but there is a category difference between them. The science of aesthetics provides guidelines, based on many centuries of ex perience, to aid and support designers.These enable them to produce objects, as inconsiderable as spoons or as imposing as airports, which are likely to please not only those who commission them in the first place, but all those who encounter the artefacts throughout their (the objects’)life. It is very important to be aware of these rules when considering the design of buildings. Genius may be able to workby instinct, but for most practitioners the secure guidance of established principles is indispensable. When one is choosing a piece of furniture for use within one’s own home, it is of course appropriate to be guided entirely by personal taste. Only those making the choice are going to have the chair or bookcase as part of their daily surroundings.Such personal choices are made on the basis of personal ex perience and ex pectation.They are conditioned by such factors as:

•

•

•

Familiarity.Everyone takes for granted the objects with which they have been surrounded from infancy, to such an ex tent that it is very hard to consider them objectively.Something is considered almost as part of the natural environment if it has long been part of a largely ignored background. One of the ways in which we commonly judge an innovation is to askourselves whether it ‘looks right’.If it harks backto norms deeply rooted in subconscious memory, it will indeed lookright because it will lookfamiliar.The form being considered may actually be an ex cellent one, but that cannot be determined purely on such spurious grounds Eclecticism. In a somewhat similar way, there are elements that appear homely and others that have an ex otic aura.When a fresh appearance is sought, for the sake of variety or to create a particular impact, an apparently easy option is to lookfor design features culled from the vocabulary of a different culture. Such elements may be imported –even to the point of eclecticism –to produce a veneer of ex citing design.This is, however, only a veneer, and the effect will rapidly pall unless the underlying design is strong. Design motifs, whether drawn from a local or an ex otic culture, a fashionable idiom or a historic one, do not in themselves constitute design, but only decoration. Fashion.There is commonly a prevailing design vocabulary, in previous eras localised but nowadays mainly international, of

AESTHETICS

•

acceptable design elements and style features.Very often these are only moved on by the great innovative movements, so that (for ex ample)Art Nouveau becomes old fashioned or minimalism becomes de rigeur.The general run of designers find themselves following such norms, which are very hard to resist.It is difficult to see how this can be avoided other than by ex ceptional minds. We are all children of our age. However, conformity to the style of a period or place is not of itself a marker of good design.There is a trap in simply being fashionable –the rules of design are sometimes ignored.They still apply. Aspiration. A designer may become anx ious to help design to progress, to be part of a great innovative movement, as referred to above. Such a designer may strive so hard to do only what is new that trusted traditional manners are discarded without proper consideration. The designers’ proper aim is to satisfy the needs and aspirations of their clients, not to establish themselves as leaders in their field.Ambition to be seen to innovate can militate against good design:a systematic designer will recognise where there is a need to find a lateral solution, and such innovation, where well judged, will be recognised.

None of us likes to believe themselves to be prejudiced, but since there is a whole system of influences which incline one towards particular attitudes, we all have to admit that these factors are likely to affect our choices, and so that, in that respect at least, we are prejudiced. The first step towards objectivity in aesthetic judgement is to identify those influences and be ready to make allowances for them when we consider our instinctive choices. Having done so, a designer is in a position to ex ercise understanding of the principles whose application is accepted as likely to result in a satisfactory outcome.As in the case of any scientific principle, these have never been given the status of absolute truth, but they have been tested in ex perience for so many hundreds of years, and relied on by so many generations of designers, that they make an ex cellent foundation for designers today.

Unity Though it would be difficult to establish a hierarchy between the principles underlying good design, there can be little doubt of the importance of unity of concept and of outcome.It is particularly necessary to emphasise this point where a team of designers is involved, since coherence cannot be achieved unless there is unanimity of aim.For this reason, it has been recommended above that some preliminary workshould be done among such a team to ensure that priorities have been agreed.

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The need for a harmonised approach goes beyond such agreement. A consistent understanding of the inevitable choices which have to be made is necessary in each of the following areas:

•

•

12.1

Colour.The theory of colour is dealt with later in this chapter.What it is necessary to stress at this point is that a whole project should be dealt with as a unity when colours are selected.This may mean that a limited colour palette has to be established, from which all selections will be made.In no case (unless very particular conditions apply)should the move from one space to another be seen as a violent transition, which means that the scheme in each must be considered as part of a whole. The approach can be especially useful if there are a number of discrete departments (or even separate buildings)within the project, whose individuality should be clear while their identity as constituents of the overall scheme is not compromised.In such a case, to select a range of colours which can be used throughout the project, while proposing emphasis on particular hues in different areas, may be a suitable strategy. It is suggested that a total of seven hues (carefully chosen for their relationships), and which can be used at various values and chromas, should be sufficient for the most complexproject. Texture.Tex ture is intimately connected with colour:the shadows cast across a surface by a rough tex ture decrease the apparent value, while a reflective surface may both increase it and heighten chroma at the same time. However, other aspects need to be taken into account. Sometimes contrasting tex tures are deliberately chosen for effect (as in some Florentine pallazzi, for ex ample that shown in Figure 12 .1. More often, it is desirable to adopt a more limited range of options, so that an urbane or a rural character can be achieved.

S c i a g ra p h y To cast the theoretical shadows on an elevation, one assumes that the sun is shining at 45 degrees vertically and horizo ntally from the left of the onlooke r. In the plan, lines are proje cted to show which parts of the elevation will be in shade. Vertical lines on the elevation repeat these points on plan. On the elevation, lines are drawn to show the angle of the sun from above.These intersect the previous set of lines to delineate the cut-off areas of shadow and sunlight. Note that the shadow cast by overhanging eaves can also be calculated. It is possible to construct such proje ctions in great detail, and where a very intricate faça de is proposed it is a very helpful ex e rcise to undertake .

12.2

AESTHETICS

•

•

•

Tex tures created by projecting structures, window openings and changes of plane need also to be considered, and the traditional art of sciagraphy has much to commend it as it is useful in determining what such effects will be. Shape. Buildings are perceived as both two- and three-dimensional forms, whose geometry can generally be easily discerned. The mind is apparently programmed to recognise the family relationship between, say, a sq uare and a cube, a triangle and a hex agon, or a circle and a cone. Without prejudicing the discussion of massing which appears below, it is necessary to indicate at this point that the introduction of a plethora of disparate two- or three-dimensional forms is unnecessarily distracting.To echo a form reinforces its impact. Unthinking repetition can induce boredom and the viewer easily loses interest.Producing a happy balance between echo and distraction is generally a suitable aim.The ways in which the hemiand semi-spherical forms of Sancta Sophia in Istanbul produced their impact deserve study. Scale. Most buildings, as is discussed in detail in Part 4, are designed to suit the use of human beings.This does not mean, however, that they must all conform to the same scale. In this sense, scale is concerned with relative size and with impact:it is most readily understood if one considers the size of the door opening that would be thought appropriate at the main entrance to a modest dwelling, a hotel or a parliament building.It has generally been felt that the doorways of great public buildings should be o ‘ ver scale’to reflect the importance of the functions housed in them. There is great charm in the miniature villages to which tourists throng, which is as much a function of their miniature scale as of the environment they depict. Similarly, law courts and council chambers will usually have high ceilings and big doorways, and gain gravitas by doing so. In such cases, ceiling and cill heights, window openings and cornices, must be similarly sized if the building is to appear consistent. Other large public buildings, such as railway stations (at any rate modern ones)and cinemas are not, on the whole, over scaled, as their proprietors wish them to seem welcoming. Dynamic.All designs contain some elements of directional movement –the eye is encouraged to move across each of them in a particular direction. In most buildings it is desirable that such movement should be contained within the composition, and under the section ‘Rhythm’, below, strategies for achieving this are mentioned. Occasionally one encounters designs where all too many directional influences are in play, and the degree of distracting noise perceived makes any ex cellent points of the composition difficult to discern.

12.3

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Failure to pay due attention to the need for harmony in all the aspects referred to impairs a design and should be rigorously eliminated.It is best if a deliberate strategy discourages their development from the outset.

P ro p o r t i o n There is sometimes confusion between the terms scale and proportion. While there is some cross-over of meaning between them, it is desirable to define their technical sense as the words are used here.

Scale is used when discussing the coherence of the elements of a building to one another and human scale in terms of their magnitude –the building is human-sized or overscale, as discussed above.Usually the q uality mentioned applies to the whole building, but occasionally the term may be used to refer to a component of it. A door that appeared unnecessarily large could be described as o ‘ ut of scale’.In conversation, one might say it was out of proportion, but that would not comply with the correct technical use of the latter term. Proportion refers to a system of ratios at the heart of a design, and this part of the section discusses the importance of such systems.

Golden Section or Golden Mean If one takes an A4 sheet of paper and turns up one corner so that the bottom edge meets one of the sides, creasing the fold, it will be found that the length of the diagonal created is ex actly that of the long side of the rectangle. If an A5 sheet (which is half A4)or an A3 one (double A4)are used instead, the same thing will be found.The phenomenon of the ratio between the dimensions demonstrated by this ex periment is that of the Golden Section.From Pythagoras’Theorem, the ratio between the sides of the sheet can be shown to be 1:√ 2 .

12.4

12.5

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AESTHETICS

According to Pythagoras’ Theorem, the area of the sq u are on the hypotenuse of a right-angle triangle is eq u al to the sum of the areas of the sq u ares on the other two sides.Therefore, if side a and side b each have a length of 1 unit, they each support a sq u are area 1 sq u are unit.The sum of those sq u ares is 2sq u are units, and so the length of the hypotenuse (h ) is the sq u are root of 2 . Since, in this case, the hypotenuse is eq u al to the length of the long side of the rectangle, the ratio between the sides of the rectangle must be 1:√ 2 .

Besides its inherent mathematical beauty, this relationship has been found for many centuries to be an ex cellent guide to the creation of satisfying proportions in design. It can be used in multiples and, while other systems come in and out of use with fashion, the pendulum generally seems to return to this position. It is known as the Golden Section, and the point of intersection between such related areas along a straight line is known as the Golden Mean.

12.6

12.7

In the short description which follows, the Golden Section will be compared to two other proportions which have been adopted at certain periods (and give particular styles some of their characteristic flavour). One produces attenuated forms, and is based on a 70 degree angle.The other is sometimes used because it is simpler to adopt than the Golden Mean, and is based on the ratio 2 :3. Proportion may be identified in at least four different fields.These have been variously named, but can be recognised as referring to one dimension, to the lines bounding a two-dimensional form, to the areas created by related two-dimensional forms, and to the faces of a threedimensional object.It must not, of course, be forgotten that buildings are three dimensional, and so the parts referred to do not necessarily lie in the same plane. In each case the ratios may be as applicable to a plan as to an elevation or section.

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Linear (Figure 12 .9).In this case, the placing of a breakor change in a linear form is selected at the point separating lengths in the chosen ratio.This might be the point chosen to place a statue in front of a façade or the division between large and small entrance gates.The ratio refers to distance and not to area. Geometric (Figure 12 .10). This proportion refers to the shape of a rectangle (or other geometric plane), and might control the height as opposed to the length of an elevation, or of a window or other component. Territorial (Figure 12 .11).Relative areas rather than relative lengths are considered in this case, so that it would be the relationship

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12.10

12.11

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between the area of a window or bank of windows to the area of the wall in which it or they were set, that would be considered. Solid (Figure 12.12). Once the third dimension comes under consideration, the proportions created on three connected planes have to be related. In a simple rectangular block, height will be a component of two differing rectangular faces, and on the plan, length and depth come together. The sophisticated mathematics becomes impractical for everyday application, and the designer’s instinct, honed by experience and by study, is probably the most practical guide.

Good proportion has always been considered to be an essential aspect of satisfactory design, and it is a worthwhile exercise to study buildings one admires (or that one knows to be generally admired)in order to analyse the proportions adopted. It will be found that this is a far more intricate matter than might appear from the outline above. To take as an example the façade of the Royal Crescent in Bath (John Wood the Younger, 1767–75), it can be observed, on visiting the site, that the relationship between the depth and width of the semi-elliptical plan, the placing of the entrances to the individual houses, the spacing of the columns, the shapes of the windows and the ratio of void to solid have all been carefully considered.

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In everyday use, most designers would emphasise the importance of the ratio of void to solid in an elevation, since this impinges most strongly on the conscious (o r subconscious)view of the passer-by, and then on the shapes of windows. It would be precious to attempt

AESTHETICS

to calculate the placing of every part of a building according to a mathematical rule. Awareness of the rule and what has generally been found to please becomes a natural part of the design strategy.

Balance The easiest way to understand the concept of balance in visual design is to conceive each element of the composition as a weight, to be counterbalanced by another. In any such composition, one of the aims is to capture the viewer’s eye, so that it rests at a focal point.In the case of an elevation, this is often a main entrance or the major mass of the grouping (the tower of Salisbury Cathedral, for ex ample).

12.14

To achieve this effect of total rest, the composition needs to be balanced about that focal point, as though it was the fulcrum on which a lever turned.There can be great subtlety in the ways in which this is managed.

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Symmetry.The most obvious techniq ue is to seekperfect symmetry, the two halves of the elevation being ex act mirror images of one another.The effect of this is usually very formal, and the opportunity to achieve it in a building depends on it being possible to arrange the accommodation symmetrically on the plan. Sometimes, near symmetry is produced, with the major masses mirroring each other while minor features differ.For this to be successful, those minor features must carry eq uivalent weight, so that the eye is not distracted nor the balance upset. Duality. It will be appreciated that symmetrical balance is most easily achieved if the fulcrum, or focal point, is marked by an important feature, and traditionally this would almost invariably be the grand entrance. An unfortunate effect, if there is no strong emphasis at the focus, is that of the eye caught between two competing masses, unsure to which it should attend.This effect is known as ‘duality’ and can be observed in some terraced streets, where neat rows of houses face one another, but there is no feature at the end of the road to hold the eye. It is an effect analogous to that of the proverbial donkey starving when placed midway between two piles of carrots. It is necessary to resolve the duality by providing such a central feature. Occult (asymmetrical) balance.The much more subtle balance which comes from arranging differing forms so as to counter one another is the more usual in design nowadays.At its simplest, this can be envisaged in terms of two children on a seesaw.The lighter needs to sit further from the fulcrum than the larger, if the two are to give each other a satisfactory game.This is because of the simple physical fact that the turning moment each ex erts is the product of the mass and length of the lever arm.

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THE DESIGN PROCESS

The eye ex periences the visual weight of the elements of a composition similarly, so that those nearer the periphery of vision gain weight from their distance from the apparent centre of gravity.A long, low wing can balance a short, sturdy one, if they are arranged appropriately.This means that as each element is added to the composition, a balancing feature will be looked for, if eq uilibrium is to be achieved. In each of these cases the ex amples given are simplistic, and they tend to be two dimensional. In the design of buildings, façades as two-dimensional pictures do often need to be considered, but it must not be forgotten that many buildings are seen from angled views as well, and the relationship between one elevation and another cannot be overlooked.As it is elevations that are drawn, there is a danger that only the two-dimensional aspects of design will be considered.

Rhythm Earlier (Figure 12 .13 above)there is a sketch of the Royal Crescent at Bath.Two of the outstanding features of the design of this façade are aspects of rhythm –repetition and dynamic. The march of the engaged Ionic columns along the length of the frontage, with their high columns and powerful entablature, is the major element of the elevation.The repetition of a strong feature like this works like a drum beat to give an underlying structure to the design, which contains, and adds discipline to, what might be a distracting number of smaller features. A similar effect can be observed where any motif is repeated –strongly marked floors on an office tower block, or a repetitive pattern of floor tiles, have similar effects. Sometimes one rhythmic pattern is contained within a stronger one.At Bath, the windows repeat in harmony.At the Palazo z Riccardi (Figure 12 .1 above), an almost syncopated relationship is set up. All such rhythmic patterns need to be contained by punctuating forms at their terminations.At Bath, this is provided by double columns, and the façades on the ends of the blockalso help to stop the eye.If such punctuation were not provided, the overall appearance would seem arbitrary, as though the elevation or floor could be stopped or continued to any desired dimension. Such repetitive patterns set up visual movement which is, in the case of buildings, because of their nature, usually horizontal or vertical. Additional apparent movement may be achieved through shape, and in the Royal Crescent this is provided by the powerful semi-ellipse of the plan.The effect of this, at its simplest, is that the spacing of the

AESTHETICS

columns as seen in perspective is subtly modulated, and even when walking along the street one is aware of the delicacy of the pattern.At Salisbury Cathedral (Figure 12 .14 above), a q uite different dynamic is produced by the soaring spire. Some buildings are designed as pieces of sculpture, where dynamic effects are the dominant features of the composition.The Guggenheim Museum in Bilbao (FrankO. Gehry, 1994–1997)is an ex ample where visual impact is achieved by an interplay of dynamic rhythms.

12.20

A strategy like this is only successful for isolated, focal buildings.In the great majority of urban settings, some conformity to surroundings is desirable, and this may often mean that rhythmic pattern is achieved more by the street or group than by an individual building.

Massing All of the aesthetic considerations discussed above have to be seen in the light of the fact that buildings are hardly ever perceived only as façades.They are three-dimensional objects, and people will move around and within them, so that the integrity of any design must be maintained from many points of view.The term ‘massing’refers to the ways in which the various blocks of an articulated building or of individual blocks in a multi-building development are seen one against the other, by an active observer. The relative sizes of the masses, their internal dynamics and the ways in which they are seen as a group, have all to be considered.It is particularly important, when a new project is being set within an ex isting townscape, that the surrounding structures of the whole environment should be taken into account.It is usually good practice to allow one blockof a group to dominate, while the others are arranged so as to enhance its impact. The Piazza San Marco in Venice is a beautifully proportioned space forming a forecourt to the cathedral.The cathedral frontage is in q uite a different style from the arcades around three sides of the sq uare but the two are sufficiently well related to form a coherent whole.As one approaches, one becomes aware that a second sq uare runs off to one’s right (the Piazzetta), and the junction between the two spaces is emphasised by the dominant Campanile (bell tower)which focuses the eye and brings the whole design together.The Piaze z tta, in its turn, runs past the Doge’s palace to the Canale Grande, where two strong freestanding columns markits end. Be aware, however, that considering the sculptural aspects of a design can mislead, unless one remains clearly aware of the points of view from which the eventual structure will be observed.The Piazza looks lovely from the top of the Campanile, but this is hardly the most usual

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C l a s s i c a l a n d ro m a n t i c d e s i g n It is often believed that the use of motifs from ancient architectural styles, such as Greeko ‘ rders’, is a markof a classical design.This is a misunderstanding. Correctly understood, a classical design is one where logic predominates, and the whole is disciplined and austere. It is comparatively static, and freq u ently symmetrical. A ‘r omantic’ one is much freer and more lively, and occult balance will more often be found. 12.24

Buildings in the Art Nouveau style are romantic in concept, while minimalist ones at the turn of the twentieth to twenty-first century are classical in intention.

vantage point.Presentations are freq uently made by designers, from which it might be inferred that a whole district would be seen from the air, or from some distant point from which, in fact, it would be invisible.

AESTHETICS

Style Having style and being stylish are not the same thing.Being stylish is following fashion, and applying lavish fashionable motifs.Having style is a matter of confident design. It is hard to avoid the trap of following fashion, but conscientious analytical design will generally be lasting in its appeal beyond what is merely trendy. Character is not imparted to a design by embellishment –indeed the only effect may be to produce an outcome that dates rapidly.A good design will be strong enough to stand alone without self-consciously trendy features.

12.25

D e c o ra t i o n It will be found a good rule always to consider the composition as an undecorated whole, and then a minimum of decoration may be used to emphasise the structural points of the composition. Decoration should never be allowed to obscure this.The overall shapes and the major composition must always be the first feature to be appreciated. This can be seen clearly in a building like the Parthenon, where the lines of the columns and entablature dominate the (q uite heavy) applied decoration.

Simplicity ‘Less is more’is almost always a good rule.William Morris told us we should ‘have nothing in your houses that you don’t know to be useful or believe to be beautiful’, and this remains a helpful mantra.It makes sense to eliminate anything in a design which neither serves a practical purpose nor, following well understood rules of aesthetics, enhances understanding of it.

Colour Appropriately used, colour can be effective in emphasising the features of a design, but it can also camouflage and obscure.It is an important component of any design, and many of the elements of a colour scheme –the permanent materials, for ex ample –are always going to control choices made in redecoration.The colours of such features need to be considered as carefully as the colours of carpet and paintwork. Colours can only be chosen sensibly if the theory of colour is understood, because like any other component of a design they need to be selected systematically.

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THE DESIGN PROCESS

It is traditional to consider three primary colours: red, blue and yellow.These are regarded as ‘p rimary’ because they are the three colours which cannot be mix e d from others, but must be found in the form of pigments. With the secondary and tertiary colours which lie between them, these twelve make up the colour wheel shown. If mix e d with blackand white, any req u ired colour can be produced. In theory, if any colour in the wheel is mixe d with the colour opposite to it (i ts complement), a completely neutral grey will be made. This does not entirely work because the pigments to which we have access are less than pure, but it is a good working rule. Colours that lie close together on the circle are said to form a harmony, while those from the opposite side are contrasts.

12.27

One essential factor to a designer is that he or she should be able to convey precisely the colour he or she has selected to the painter, dyer or printer, so that their intentions can be carried out accurately. The ‘M unsell’ system is an effective way of identifying precise colours.The idea of the Munsell colour chart is that the steps or gradations of each of the three dimensions of colour can be q u antified, the dimensions being hue, chroma and value. Because of this, any colour can be accurately reproduced from a formula.

hues , hue being that characteristic of colour by which Around the eq u ator of Figure 12 .8 are arranged the we distinguish red from blue. Instead of the three primary colours placed eq u ally around the perimeter of the colour wheel, five primary hues are recognised in the Munsell system –red, yellow, green, blue and purple.These are chosen as primaries as they are in (n early) even gradations of wavelength. When these are evenly arranged around a circle a much closer approx i mation to the proportions of the colours present in

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AESTHETICS

133

white light is obtained. Five intermediate hues are also recognised, and the steps between can be defined – usually limited to four at each stage.This means that 40 different hues are immediately identifiable, with no limit to the further subdivisions that could be obtained. Not all the hues that lie on this eq u ator will be at their fullest intensity.This system take s into account the fact that with some pigments a much stronger colour can be obtained than with others.This characteristic of colour is called chroma and spoke s radiating from the centre of the diagram bear regular marke d steps indicating the chroma of the hues.The dullest colours, of course, are those of ‘l ow chroma’, lying at the centre of the diagram, while the brightest are those of ‘h igh chroma’ at the ex t remities of the radii. The third dimension is that of value (l ightness or darkn ess) and is indicated on a scale running vertically through the centre of the diagram. White (h igh value) is at the top and black(l ow value) is at the bottom. There is a direct (i f approx i mate) relationship between value and the reflection factor. Value multiplied by value –1 (V (V-l)) gives the figure –so a value of 6 is eq u ivalent to a reflectance of about 6 x5 =30% . Any hue can have any chroma from nil to the maximum obtainable with the available pigments, as well as any value between blackand white, and all of these three characteristics can be q u antified.The diagram represents a three-dimensional solid –all the spaces between the arms could be filled in with possible colours. A Munsell atlas is published, giving chips and formulae for several hundred colours. While there will always be the need for the ‘a rtist’s eye’ in preparing the most subtle colour schemes, the kn owledge of colour available through the Munsell classification make s it possible for everyone to avoid the worst clashes, since the relationships between colours are clear.

Colour schemes Further guidelines based on observed phenomena, which should be borne in mind by anyone putting together a colour scheme, include the points mentioned below.

Psychological effects

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Some colours have the effect of apparently creating warmth while others have a cool effect.The blue/green side of the colour diagram is the cool side, while reds and oranges are categorised as ‘warm’. Some hues, we are told by psychologists, have a stimulating effect, while others have a calming effect.Blue/greens are soothing, while red/purples are aggressive.This effect is also related to chroma, with high chromas having the greatest impact. An effect of recession or advance is associated with particular colours.In general, warm colours advance while cool ones appear to recede –and this can affect the apparent shape of a space in which they are used.

The cumulative effect of these points is shown in Figure 12 .2 9.

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Practical guidelines Any colour scheme which is to retain interest for any length of time needs to contain within it –and usually within a very limited palette of colours –three separate kinds of contrast:

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Contrast of hue. A scheme made up entirely of harmonious colours may be very restful, but will lack‘bite’ and the selected colours will lose their impact.A contrasting hue sets off and intensifies the harmony and rests the eye. Contrast of value.There should always be some variation between darker and lighter colours. Contrast of chroma. A scheme consisting entirely of saturated colours would be naive and crude, while one made up from low chroma hues could well be monotonous.

Having taken all the above points regarding the choice of colour into account, it is easy to fall into the twin traps of over elaboration on the one hand or ex cessive austerity on the other.An approach which will avoid either of these pitfalls would be to limit the ‘palette’ of hues to two contrasted sets of three harmonies, and then to use these colours in various combinations of value and chroma throughout the building. This approach of preparing a limited range of colours for a job takes care automatically of the view from one space into another (perhaps through an open door), which may often be overlooked.In particular in the small job, such as a single house.One simple scheme for the whole

AESTHETICS

will virtually always be more successful than schemes for individual spaces prepared piecemeal.

Selection All of the aspects of design which have been considered in this chapter apply as much to objects being chosen from commercial sources as to those being designed from first principles. It is usual for buildings to be composed almost entirely from manufactured components, and considerable care is needed to ensure that these are mutually compatible in their design characteristics.

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Chapter 13

Evaluation

In spite of the continuous cycle of evaluation and adjustment that is integral to the development of any design, it is necessary to carry out a formal assessment when the process is believed to be complete. Hindsight is a wonderful thing.It is almost always possible to lookat a completed proposal and see how it could have been improved, if only a little more time had been available, or information now to hand had been discovered earlier.The process of developing a design is subject to constraints of time and cost, and the best that can be done is to use those resources in a disciplined and efficient way to obtain the best available outcome. It is very rare indeed for any design to be perfect in all respects.What is essential is to establish that the req uirements of the brief have been correctly interpreted, that the priorities have been respected and that the best all-round solution which can be discerned within the parameters of the problem has been obtained. This evaluation needs to be systematic. It must not be overly influenced by the prejudices of individuals.We all know that we have likes and dislikes, conditioned by subliminal forces of which we are probably unaware, although it is reasonable that the training and ex perience of professionals should be given more weight than the less informed opinions of lay people. It is helpful, for this reason, if the assessment is carried out co-operatively between two or more members of the design team, using the brief as their guide.It can also be useful to have the input of an ex perienced designer who has not been a member of the team, and can bring a fresh eye to the proposals.This assessment should be completed before the opinion of the client is sought.

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13.1

It can be useful to structure the process around the key diagram in Figure 13.1 which also appeared earlier.The sixcomponents which make up this whole cover the important areas that need to be addressed. It will be understood, though, that the order in which the segments are dealt with here cannot represent the priority each is to be accorded, which will arise from the conditions of the specific brief. Usually the q uestions will need to be ex panded, to reflect the details of the project.

Aesthetics (‘delight’) In use This refers to the ex pected response of those using the building to its proportions, dynamic, play of light, colours and so on.It is important to consider both the regular occupant and the occasional visitor.This is probably the most vital (and most difficult)area in which to maintain objectivity.

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Is the internal character of the building appropriate to its purpose? It is important that a residential home should seem warm and inviting, while a hospital should appear clinically clean though non-threatening.An effort of imagination by the scrutineers may be needed to assess the success of the design in this respect.

E V A L U AT I O N

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Is it unified in its character? Spaces which are in themselves delightful may be spoiled because they are out of harmony with others.Simplicity –lackof variation for its own sake –should be sought. How pleasant is it to use? Some assessment should be made of how eager people would be to revisit the building. Are the spaces well proportioned? The relationships between the dimensions of spaces, as well as those between one space and those adjoining it, need to have been carefully considered. Does the internal design conform to accepted rules of proportion, rhythm and so on? If the guidelines suggested in Chapter 12have not been followed, it should be possible to state clearly why this is the case.

Environmental pleasure

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Does the overall appearance of the building conform to formal rules? A formal evaluation should be made of the proportions and balance of the composition as seen from a variety of angles.This is best done by making a series of small-scale drawings and taking actual measurements. Does it conform to the scale and character of the surroundings? How successfully does the design reflect o ( r complement)the scale and proportions, materials and style of those in the vicinity? Has the relationship to any open spaces and avenues been taken into account? Is the structural system expressed? Is it evident whether the building is framed or of load bearing masonry? Are the decorative features ex pressions of the construction, rather than arbitrary additions? Is the purpose of the building apparent? Would a passer-by be able to make a reasonable guess as to whether the building was a public office or a place of entertainment, a transport interchange or an educational establishment, without looking for the direction signs?

Function (‘commodity’) Usefulness

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Is the building easy to navigate? Are different areas sufficiently well-defined for users not to feel lost?

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THE DESIGN PROCESS

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Is the route between related areas easy to follow?Buildings with few windows can be disorienting, as can those with maze -like circulation areas. Are the spaces suitable for their purpose? Have the shapes and sizes of rooms been arranged so that the necessary furniture and eq uipment can be well placed and comfortably used? Are the spaces well arranged in relation to one another? Are the most commonly used routes between spaces the shortest? Has any necessary segregation (for ex ample between witnesses in a court house, or for sterile areas in a hospital) been provided without undue inconvenience for users?

Cost

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Is the estimated first cost within the budget? If not, is sound justification for the overrun provided? Have the lifecycle costs been calculated and are they appropriate? What economic life has been proposed for the building, and what allowances have been made for the cost of borrowing and for inflation? Have the costs of replacements, energy use, obsolescence and disposal been taken into account?

Te c h n o l o g y ( ‘ f i r m n e s s ’ ) Materials

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Have suitable materials been selected for the area and for the type of building? Have high-tech or low-tech choices been made, and if so are they justified? Have the energy-costs of the materials, in production and transport, been considered? Have local materials been preferred where possible? Are the internal and ex ternal finishes durable or will they req uire regular maintenance? Have potential problems with vandalism been taken into account?

Methods

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Is the structural system well understood and suitable? Has the system been chosen to fulfil the req uirements of the functional building, rather than to demonstrate the advanced skills of the designers? Are the dimensional constraints such as to allow suitable tolerances for inaccuracy and for handling?

E V A L U AT I O N

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Have any problems such as the three-dimensional location of members in space been allowed for? Has the scheduling of construction with the manufacture and delivery of components been considered? Are the skills required for construction available locally? For ex ample, if the design is for self-build homes, or for emergency shelters, the available skills must be assessed and accommodated.

External scrutiny In addition to this internal screening, the proposals will be subject to scrutiny by a number of other agencies, each with its own imperatives. Each of these bodies will have an individual point of view, and discussion of their perceptions of the success of the design can be salutary. Comments received should be taken seriously as, even when they do not (as may often be the case)carry mandatory force, they are a good representation of potential public reaction to the proposals. Scrutineers are likely to include the following:

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The financiers backing the project. Few, if any, bodies advance grants or loans without the assurance that they will receive value in return.This may be in terms of the provision of public good or of useful accommodation, or of annual return in rents as well as the protection of their capital.They will also be interested in the residual value of the property at the end of its economic life. Freeholders in the case of leasehold land.Many leasehold properties are subject to established constraints on the uses to which land may be put but also on the nature of the buildings which may be constructed.These may include conditions about height, materials, density of development and other matters. Such constraints are especially common in large urban estates, where the freeholders’ aim is to protect the value of properties individually and as a whole in the area.The conditions are to the benefit of all leaseholders, including those erecting new properties, and so, though sometimes onerous, they are usually beneficial on balance. The potential users of the accommodation.This is an area that can be addressed in a wide variety of ways, from a public ex hibition and invitation for comment at one ex treme, to an informal discussion with staff not involved in the briefing at the other. Such ex hibitions and discussions are often seen as an opportunity to ‘sell’the scheme, and indeed so they can be, especially if this leads to a vocal group feeling that it o ‘ wns’ the proje ct. However, it can be valuable to listen to any doubts that are ex pressed, as they are coming from people who have not been

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living with the developing ideas, and may cast a new light on what is being decided. The town planning authority.The LA will pay special attention if a conservation area or national parkis involved, but are in any case obliged to enforce the req uirements of national and local planning legislation.

In addition there will be purely technical appraisals by, for ex ample:

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the Building Surveyors’ Department under the Building Regulations; the Fire Department to ensure escape routes and appliance access; the Licensing Authority where a license for entertainment or liq uor is req uired;and the police, to advise on crime prevention and security.

It is wise for these last bodies to be approached at the design stage, so that their req uirements can be fully integrated into the contact documentation.It is to be hoped that their req uirements will have been fully taken into account, so that no late problems arise in these areas.

O v e ra l l It is sometimes found useful to invite each of the bodies assessing the project to award points (perhaps out of 10)for each of the sixareas of appraisal, so that an objective final judgement can be given. If the whole of this process is carried out objectively, both those who know the project best and those to whom it is new will have had the opportunity to ex press their views, and a considered and reliable decision on its viability can be given. Note that while all design decisions should have been taken before the contract documents are finalised, design remains an ongoing commitment:

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first, because careful supervision by the designers (in addition to technical supervision)is needed to ensure that the design intentions are being fulfilled;and second, because contingencies may arise which demand changes to the project, and it is important that these are made in full knowledge of the reasons for the original proposals.

It is not good practice for the supervision of construction on site to be entirely delegated to specialist teams, however valuable the input of an ex perienced building manager or clerkof works may be.The design team need to remain in overall control of the works until completion, in order to ensure that their intentions (and the wishes of the client)are fully carried out.

Chapter 14

Completion P ra c t i c a l c o m p l e t i o n The responsibility of the design team for the success of the project continues up to and beyond the handover of the site to the owner.When the workhas effectively been completed, it is the team’s job to make a detailed inspection of the building with the contractor, and to prepare a report setting out all those matters which remain to be resolved or completed.It is within their authority to refuse to accept ‘practical completion’if the ex tent of the outstanding workwould make it unreasonable to ex pect the client to take over the building. Up to this point, and under most British contracts, the client has had access to the site only at the discretion, and with the permission, of the contractor, but at practical completion this situation is reversed. Assuming that practical completion is certified, responsibility for the site (including all insurances)is transferred to the owner, and subseq uently it is the contractor who must askpermission to enter the site –and to complete the outstanding work.This period is known as the ‘maintenance period’. Under most contracts, all of the items included in the report have to be dealt with to the satisfaction of the designer (not the owner, occupier or administrator, though they will of course be consulted), within the sixmonths’maintenance period, at the end of which a further inspection is made.The final certification of completion is not, however, issued until every item, including defects discerned during the maintenance period, has been satisfactory resolved. Since during this period the owner or occupant may become aware of unanticipated points about the building which he or she dislikes, but which are not faults caused by poor materials or defective work manship,

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the designers may have a diplomatic role to play.The contractor is not responsible for design faults, but the owner may find it hard to accept that these result from faulty briefing o ( r incompetent design)and should have been recognised and corrected earlier. Sometimes apparent faults arise from a failure of the client to understand the proper use or maintenance of plant, fittings or finishes in his or her building. For ex ample, users who are unfamiliar with particular types of shower fitting may find them difficult to control, or the wrong detergent may be used on finishes, resulting in damage.These and similar events can be largely eliminated if owners are provided with appropriate information, and this can most successfully be done by the preparation of a users’ guide, or owner’s manual, referred to briefly in Chapter 8.

O w n e r ’s m a n u a l This guide or packmay include the following material, depending on the nature of the building:

Drawings Copies of the construction drawings are unsuitable, as they will include much material which is redundant to this purpose, and which is likely to cause confusion.The specially prepared drawings should be simple and easy to read, and should show:

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orientation; site boundaries and adjoining structures; public rights of way; dimensions; positions of all main services, with access and cut-off points; runs of all internal services with access and cut-off points;and positions of fire alarms and appliances.

Plant and appliances Manufacturers’data, including:

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model numbers; serial numbers; manufacturer’s or agent’s contact details; instructions for use and maintenance;and guidance on removal for replacement.

COMPLETION

Materials and finishes These should include:

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name and technical description; supplier;and instructions for regular cleaning.

Contact addresses These should include:

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design firms, indicating the specific responsibility in each case; the general contractor and major subcontractors;and the police and other emergency services.

It is important that this material should be available not only to the owners of the building but to those who maintain and use it on a daily basis.

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Part 3

Bibliography Allen, William (1980) How Buildings Work. New York and Oxford: Oxford University Press. Brown, Stephen (1983) Design Processes and Products. Everyday Objects. Milton Keynes: Open University. De Bono, Edward (1967) The Uses of Lateral Thinking. London: Jonathan Cape. Le Corbusier (trans. Etchells, Frederick) (1931) Towards a New Architecture. London: Rodker. Mitchell, William J. (1990) The Logic of Architecture. Cambridge, Mass, and London: MIT Press. Pearl, Danny (2004) An integrated design process. Canadian Architect, June. Petroski, Henry (1993) The Evolution of Useful Things. London: Pavilion. Smith, Peter F. (2003) The Dynamics of Delight. London: Taylor and Francis. Walker, David (1983) Design Processes: An Introduction to Design. Milton Keynes: Open University. Wiseman, Richard (2004) Did you spot the Gorilla? London: Arrow. Zunde, Joan (1982) Design Procedures. London and New York: Longman.

Webliography www.cis.rit.edu/mcsl/about/chromazone (22 August 2005) www.ergonomics.org.uk (22 August 2005) www.statsoftinc.com/textbook/stathome.html (22 August 2005)

Part 4 Space

INTRODUCTION, 151 Chapter 15 TAILORED VERSUS LOOSE-FIT OUTCOMES, 153 Machines for living in, 153 Short-term building, 156 Demountable buildings, 157 The loose-fit solution, 158 Summary, 159 Chapter 16 FUNCTIONAL REQUIREMENTS, 161 Published sources of information, 161 The internet, 163 The client, 164 The briefing chart, 164 Summary, 168 Chapter 17 ANTHROPOMETRICS AND ERGONOMICS, 169 Anthropometrics, 170 Static anthropometrics, 173 Dynamic anthropometrics, 175 Ergonomics, 177 Sources of information, 178 Summary, 178 Chapter 18 RELATIONSHIPS BETWEEN SPACES, 179 The circulation diagram, 179 Relationships between spaces, 184 The optimum arrangement, 186 Summary, 189 BIBLIOGRAPHY, 191

Part 4

Introduction

The most vital of the functions served by almost any building is the provision of useful space. That is to say, individual spaces which fit the activities to be performed in them and are conveniently arranged in relation to those accommodating other functions. The provision of acceptable conditions within these spaces is discussed elsewhere. Chapter 15 discusses the advantages and problems associated with highly functional buildings. The techniques for assessing the spatial requirements of buildings are introduced in Chapter 16 with detailed discussion of the briefing process. There is a discussion of the methods by which appropriate arrangements to accommodate the varied functions defined by the client’s brief can be selected. In Chapter 17, the spaces required by persons performing varied functions are discussed, with an introduction to anthropometry. The appropriate arrangement of spaces to accommodate the varied functions is considered in Chapter18, including the use of the circulation diagram. In particular, the structural and other constraints within which planning decisions must be made are taken into account throughout the Part.

Chapter 15

Tailored versus loose-fit outcomes Machines for living in One of the most influential architects of the twentieth century, Le Corbusier (Charles Edouard Jeanneret 1887–1965)declared in Vers une Architecture (Towards a New Architecture, 1923) that houses were ‘machines for living in’. This was to become a mantra for generations of designers. The principle of insisting on buildings that perfectly fitted their perceived functions, without redundant space or features, underlies most of the architecture of the century, and its imperative of achieving a tailor-made fit was pursued as a virtually moral quest. The technical ability to construct spaces of whatever size and shape a designer dreamed up, with huge spans uninterrupted by minimised supporting members, had made it possible to ignore most structural constraints. It was no longer essential to fit activities within predetermined structural bays. This allowed more detailed examination of the uses to which buildings were going to be put by their occupants, and his followers took Le Corbusier’s dictum very seriously, tailor-making their buildings to accommodate precisely determined functions. It was also believed, again derived from a misunderstanding of a Le Corbusier text, that such a building would, faux de mieux, be beautiful. He had pointed to the accepted grace of traditional objects, evolved over centuries to serve a purpose using locally found materials with locally evolved skills, and also to the delightful shapes of cars and aeroplanes, which used new technologies to fulfil new purposes. He did not intend to propose that appearance could be ignored, but he was widely interpreted as doing so. This was, in fact, to misunderstand the Master. He described architecture as ‘the intelligent, correct and wonderful play of united bodies in

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light’, and was himself fascinated by classical designers such as Vitruvius, Caesar’s designer in the first century AD, who wrote extensively on the architecture of his day. He also studied and appreciated the Renaissance architect Andrea Palladio (1508–1580). Palladio’s seminal work on a system of proportion in Quattro Libri dell'Architettura (The Four Books of Architecture, 1570)and the idea of Virtuvian Man, most familiar to us as used by Leonardo da Vinci, underlay Le Corbusier’s own theory of proportion, published in Le Modulor (1948). This relates the whole and the integral parts of a building to the proportions of the human figure, and has been hugely influential. This is discussed further in the section Anthropometry’ ‘ below. 15.1

Le Corbusier did not, in fact, deviate significantly from the beliefs of an earlier theorist, Sir Henry Wotton (1568–1639)who set out to distil the essence of Vitruvius’ work in Elements of Architecture (1624), where he stated that, as quoted before: ‘In architecture, as in all other Operative Arts, the end must direct the Operation. The end is to build well. Well building hath three Conditions. Commodity, Firmness and Delight.’

15.2

The balance between those elements, which can be defined in modern terms as function, technology and beauty, is a better interpretation of Le Corbusier’s legacy than insistence on function alone. Buildings which are designed purely as envelopes for closely specified functions suffer from a number of potential faults:

•

•

15.3

Their use may be tolerable only for comparatively short periods. Touring caravans provide wonderfully compact tailor-made accommodation for a holiday, but few, other than nomads, would choose to live in them in the long term. They are frequently very difficult to adapt. The ways in which people work and relax change over the years, and they need furniture to be arranged differently, and sometimes for the relationship

15.4

TA I L O R E D V E R S U S L O O S E - F I T O U T C O M E S

•

•

between the activities accommodated to be changed. This is not only the case with a manufacturing process, it can also be true of family life. Whereas 50 years ago almost all family meals were taken as a group around a dining table, this is much rarer today. Figures 15.3 and 15.4 show the plans of houses designed in the 1920s and 1990s respectively, and responding to the change in living requirements which had occurred during that period. There are cases of buildings which enforce patterns of behaviour that are no longer those the occupants prefer, or even require. A church lovingly designed and built in the 1960s was meant to be used for a particular liturgical style which the congregation now wish to change, but they are unable to do so. It assumes an informal, participatory pattern of worship, and is extremely difficult to use for formal processions –even bride and groom need to part to pass the font on their way out of church. They can cost more than necessary. Designers may have paid so much attention to the arrangement of space that a sensible application of appropriate building methods was overlooked. This can mean that they are unnecessarily expensive. Small compromises, for example in standardising bay sizes, may make significant financial savings. They can, on occasion, be quite outstandingly ugly. The basic principles of aesthetic design cannot be ignored, if a successful outcome is to be found.

15.5

15.6

Nonetheless, the most important element of any building is the space which it contains and defines and, in particular, the way in which this space is experienced. All the other parts exist only to accommodate that space in a suitably economic and practical way –any other structure would be a folly or stage setting and not truly a building, certainly not a piece of architecture. In this, buildings differ from most other structures, such as bridges or dams. In those cases, the proper response of the structure to the defined function is, of course, paramount, but the intricate relationship between spaces which are to accommodate a multiplicity of functions does not exist. Buildings, therefore, have to be arranged so as to accommodate the known or expected functions comfortably, but the likelihood of changes in requirements after a time almost always needs to be taken into account. It is possible to identify a number of ways in which this can be done. These might include:

• • •

the disposable building, planned for a limited life; construction with demountable parts, so that the configuration of the accommodation could be changed;and a loose-fit solution, where additional space was allowed for modest changes of use.

15.7

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15.8

Part of any decision between such alternatives must naturally be a lifecycle cost projection, taking in first cost and running costs as well as the costs of adaptation. This is known as a terotechnological assessment, and the elements are shown symbolically in Figure 15.8. Not all of these options will be equally appropriate in each case.

Short-term building Where it is clear that the useful life of a building will be limited, as in the case of pavilions put up for specific events such as exhibitions, it is of course commonplace for them to be designed solely for their immediate purpose, with limited-life materials, and there is no need to look at their long-term prospects. Such an approach is perfectly feasible for many medium-term buildings. Indeed, in some advanced societies it has become usual to erect commercial buildings on a short-term basis, preferring demolition and rebuilding to the inevitable compromises inherent in adaptation in such cases. It is, it would seem, calculated that the additional cost of taking this path outweighs the inefficiency of working in less than ideal premises. The process can be managed in different ways:

•

It may be proposed that the new building will occupy the same site as the first one, especially where its relationship to others is important, for example as part of a hospital or manufacturing complex. In such cases, important capital savings can be made, as less durable materials and plant can be chosen, and maintenance is less critical, since the life of the building does not have to be maximised.


•

•

157

However, there are costs involved in the handover period, where the length of the construction period and the need for temporary accommodation have to be calculated. Alternatively, it can be assumed that the original building, though designed precisely for a defined purpose, will nonetheless have a residual value when it ceases to be used by the original occupier. In this case, new premises will be built elsewhere, and the first premises occupied until the new one is available. There will be smaller savings in the first cost, since a saleable asset is to be produced, but the inconvenience of a move into temporary accommodation can be avoided. However, the siting of new accommodation, in relation to the rest of a complex, may have to be less than ideal. This might be less vital in the case of, say, a building on a university campus or one element of a sports development, while in some cases suitable temporary accommodation might be difficult to find. It needs to be appreciated that choosing a site for premises which are eventually to be sold may compromise the ideal original placing, since the situation is an essential part of the value of a building. The building may be the subject of a rolling programme of rebuilding, so that only a small part of the operation is inconvenienced at one time. A corollary of this is that there will always be part of the building which cannot be used, and therefore it has to be larger than would otherwise be the case. This has generally only been a suitable solution for very specialised accommodation, and where security and continuity were of great importance, as in the case of sensitive research facilities.

Demountable buildings A child’s set of building blocks is inherently adaptable. The same units can be configured in a large variety of ways to produce different outcomes. Although ‘buildings’ made from such blocks do not have to provide the security or the weather resistance of real edifices, they provide clues as to how real buildings can be capable of responding to changes in demand. In the latter half of the twentieth century, a great deal of work was done in the field of system building, and many public buildings, especially schools, were built from prefabricated parts. A successful prefabricated system presupposes:

• •

dimensional co-ordination, so that all the parts relate to one another, and to a structural three-dimensional grid on which the plan is laid out;and compatible, usually dry, joints, for integrity against movement and weather. 15.9

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A very large variety of different buildings could be produced from what was essentially the same kit of parts (though they all looked very alike). Such construction was ‘dry’ in that the joints were protected by careful design and by gaskets. They could be taken apart without damage. Although, in theory, these buildings were demountable, this was rarely attempted, except in the case of exhibition buildings and temporary structures such as site huts. There was considerable popular prejudice against p ‘ refabs’ because they were not thought to display craftsmanship, although virtually all parts of all buildings are factory made and merely assembled on site. Commercial fabrication, in the controlled conditions of a factory environment, ensures consistent quality and continuous production, whereas site work is subject to the vagaries of the weather. In the case of the system buildings of the late twentieth century, all the parts were usually manufactured by a single entrepreneur, and compatibility was ensured. The movement towards factory production, however, together with such theoretical work as Le Corbusier’s Modulor, referred to above, accelerated interest in modular co-ordination, and many parts were eventually made to standard sizes by a variety of competing manufacturers. The necessary development of standardised joints did not develop at the same pace, and so while there is no theoretical objection to the general adoption of dry construction, and therefore demountable buildings, this has not been widespread. A much more common approach has been to design large covered spaces, more or less conventionally constructed, but for the interior arrangements to be flexible. To achieve this, it is essential to:

• •

15.10

keep the floor as empty of structural features and service ducts as possible;and arrange service points on a regular grid, generally with in-floor access points, so that no point is remote from necessary services.

By then providing a partition system which can be rapidly changed, which does not carry services, and which can have a variety of parts to provide sound protection, light, privacy and so on as required, a building which can respond rapidly to changed needs can be produced. Le Centre Pompidou (T he Beaubourg) in Paris (Rogers and Piano, 1972–1976)is an excellent example of such a building. In this case, the stairs and escalators, and all the services, run outside the main fabric, so that the floor space is entirely clear for ever-changing exhibitions.

The loose-fit solution Another strategy, and one that in many cases may be preferred, for ensuring that a building will provide useful space in the long term, is


to create spaces which can be used in a number of ways. Instead, for example, of creating suites of offices opening from one another, separate access might be arranged from a general circulation space. If this is done, the number of rooms used by a particular department can be varied to meet changed needs, without alterations to the building being necessary. An alternative choice could be to make each space a little larger than the minimum that is strictly necessary, allowing for its use to be changed or just for the rearrangement of furniture. The advantage of this approach is that the useful life of the building is extended without the disruption of alterations or removal. Against this, the first cost of the project will be increased, since additional space which might be thought redundant is provided.

Summary It is important to understand the nuances of these strategies, and the conditions under which one or another may be found appropriate. Some accommodation must be accurately tailored to need –an operating theatre suite, for example. A library, however, needs to be capable of change, since the ways in which books are stored and displayed may well be altered. The stock will inevitably expand.

15.11

Generally, spaces to be used by groups of people with simple furniture (classrooms, offices)are probably best designed on a loose-fit basis, while spaces where heavy or sophisticated equipment is used (factories, laboratories)need to be precisely designed. It is interesting to consider the evolution of the suburban house during the last century. After the First World War, the Howard report proposed ‘homes fit for heroes’ and suggested that each should have two living rooms and a kitchen, two double bedrooms and a single one, and a bathroom. This pattern became very common indeed, and it was taken for granted that food was cooked in one space and eaten in another, while a parlour was set aside for more formal use. Sometimes doors were inconveniently placed, or rooms were of awkward shapes, making them hard to furnish, although they fell within the rules.

15.12

To provide rapidly for housing needs immediately after the Second World War, prefabricated houses intended to be temporary were built. These were very carefully designed around service cores, and were a very tight-fit solution to basic needs. They were quite unalterable. The Parker Morris report (1961)took a different approach. Instead of specifying rooms, it set out over-all floor area. Among many far-sighted guidelines, the regulations which followed required plans submitted for approval to show the main items of furniture, in order to demonstrate

15.13

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15.14

that the spaces could be used sensibly, with adequate circulation space around the pieces. Three possible living area arrangements were envisaged –kitchen-dining room, sitting-dining room and the old three-space type of plan (Figure 15.4). Houses built under these rules proved far more adaptable to changing patterns of family life. Such considerations could be extrapolated to apply to public and commercial buildings. A choice can only be made between the options discussed in this chapter –short life, adaptable building or loose fit –by the client. The client needs to have the opportunity to cost each strategy over the life of the proposed building, and must be encouraged to do so in full understanding of the factors involved. The client’s decision will then become part of the design brief. It is not appropriate here to set out the detail of the terotechnological calculations required, but these are dealt with, along with other financial concerns, in Volume 4, Practice, Management and Responsibility.

Chapter 16

Functional requirements P u b l i s h e d s o u rc e s o f i n f o r m a t i o n Since buildings exist to contain useful space, work on preparing a design cannot begin until the nature of the space required has been determined. It should never be taken for granted that the answers to all the questions of size, aspect, temperature and the many other characteristics required can be understood intuitively. It is essential to obtain the information systematically and to record it in an easily recoverable form, if no vital element is to be overlooked. The office library is an essential first resource. If it is to be reliable, it must be kept up to date and properly catalogued. It is helpful to adopt the CI/SfB classification system, commonly used in the industry, the references to which generally appear on trade literature. A full guide to classification is given in the RIBA Product Selector volume 2. Out-of-date publications should be ruthlessly culled. It is good practice when consulting any published material to be aware of the reliability of the source, the intended reader and the purpose for which it was produced. One should ask:

• • •

what information is needed for the present purpose? who produced the information and for what purpose?It is especially important to be wary of material specifically prepared to boost sales;and is it up to date?

In the UK, the four main sources of published information in printed form are the following:

•

Government and quasi-governmental material, in the form of Building Regulations, Planning Acts, Health and Safety Regulations

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•

and other relevant legal requirements. These are a necessary prerequisite of any project. It is also important to consider European legislation, and, if designing for a site outside the EU, whatever local legislative framework applies. Within this material will lie the overall parameters within which any solution must fall, and following it will usually be a requirement if permissions (and often funding)are to be obtained. It does not, at least in the UK, include mandatory solutions, since the circumstances of every case vary and must be taken into account. The requirements may seem (especially to those inexperienced in the industry)to be draconian, but they are based on real experience of actual cases. All of this is to be assumed to be a proper guide, and used as though mandatory unless there are clear indications to the contrary. Government departments also publish useful design guidance bulletins, such as the Housing Bulletins, and regulations such as those advising on the design of school buildings or hospitals. Within these publications there are helpful guidelines drawing on many years of experience of particular building types. This information may establish minimum areas, desirable arrangement for escape routes, storage requirements and so on in a generalised way. While suggestions of possible solutions may be included, they cannot usually be taken to be appropriate in every case. They are there to show what can be done rather than what should or must be. Local government also publishes design guides which may helpfully indicate what is generally considered acceptable to the planning authority. These have to be taken especially seriously in the case of conservation areas. The information referred to under this heading establishes the environment in which the design solution is to be evolved. Those parts of it referring specifically to space requirements tend to set acceptable minima rather than optimal areas. Materials published by trade sources, and most especially in Britain by the Building Research Establishment (BRE). The research establishments, both quasi-governmental and those maintained by the trade organisations, have enviable reputations for objectivity, as well as extensive resources. Their work is continuous, and the most up-to-date versions of their bulletins should always be used. Note, however, that while guidance on the structural use of (for example) a particular metal, provided by a trade organisation, should define the precise characteristics of that material and will probably suggest the optimum uses of a variety of alloys and cross-sections, it will not necessarily be a good guide to selecting one material from among a number of possibilities.

FUNCTIONAL REQUIREMENTS

•

•

Trade literature, put out by specific manufacturers, which is designed to promote specific products, can also be useful for its factual content, particularly of conditions in which the use of the product is recommended, so long as it is read warily. It is not in the interests of manufacturers to mislead consumers, whose loyalty is important to their growth. In the present context, the manufacturers’ information on dimensions and weights is especially relevant. Professional magazines. The material which can be culled from professional magazines can be considered under three headings: — first, there are factual reviews of recent projects and research, which indicate the state of thinking in the profession and may give useful pointers to further sources of relevant information. It is important to remember that any completed buildings described were designed many months previously, and so do not reflect the most recent developments; — second, there is the editorial matter, which may include comments on such topics. The paper may have an editorial policy, perhaps of promoting ‘green’ issues or of supporting ‘fair trade’ options, which might need to be taken into account. Care should be taken to differentiate between factual articles and critical assessment of projects;and — third, there are copious advertisements which, while they may assist in the accumulation of an office library, are unlikely to provide immediately useful information. They are there to provoke questions, not to supply answers.

The internet Many of the publications referred to above are also available to download (sometimes for a fee)from the internet, and the versions posted online should be the most up-to-date available. There is copious additional information, some of it ephemeral. The internet can be a snare for the unwary, however. There are important national variations in requirements, and it is sometimes difficult to differentiate between materials appropriate to specific cultures or climates. More importantly, there is much opportunist publishing on the web, and the same care should be exercised in using the materials downloaded as would be applied to the use of locally printed literature. It is, however, useful to have the internet addresses of trusted sources bookmarked.

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The client The most important source of the necessary information must, of course, be the stated requirements of the client. He or she may well require help to establish what these are, since it is very common for people to think in terms of accommodation they have experienced previously, and to suggest how this might be modified to make it more satisfactory. They will also have seen buildings elsewhere, which they believe might suit their purposes, and set out to describe them.

It is vital to keep in mind the reiterated message –the client articulates the problem, the designer develops the solution. The designer needs to understand the following clearly:

•

• •

•

Who will use the building? Note that this may include the people who administer the site, those for whom it is a place of work and those who visit it for any purpose. The requirements of people with disabilities have to be taken into account in the case of public buildings, and may need to be in other cases too. What they will do in it? This must include not only the planned activity but also unplanned ones, like escape in case of fire. The conditions under which this can be done most efficiently. An understanding of both physiological and psychological reactions may be necessary in some cases. Where the latter are critical, the client is a likely source of information. One example is that the low window cills in high buildings may inspire panic unless there is an evident guard rail. What equipment they will require. Heavy but moveable machinery, moveable furniture and personal equipment like computers all make spatial demands, and so the need for them has to be known before space requirements can be properly assessed.

The briefing chart The briefing chart is an extremely helpful tool from which detailed, useful information can be obtained without the prejudice of a predetermined outcome. It is a document which is to be completed by the client, and must represent his requirements, but he or she is likely to need help in filling it in so that it is informative to the designers. In the case of a simple building, the chart might take the form shown in Figure 16.1. This refers to a small woodworking shop. On the left hand side, all the activities to be accommodated are listed, whether it is envisaged that they will require a separate space or not. They may not necessarily appear in what seems a rational or organic order –this is not a guide to the sequence in which activities occur. In the example shown, the order seems entirely arbitrary, and activ-

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JOB NO MNO

BRIEFING CHART

JONES and JONES

Activity

Arrangement

Shape

share with next to

Features

near to level aspect size

Enter

Con, Rec

Admin GF

3sq m

Mats in

Con, Sec

Mat st GF

3sq m

Mats. Storage

Woodwork

JOINERY SHOP

equipmlight

Remarks

humid- temp.power floor

15sq m

Control

Sec, Rec

2sq m

Security

Control

2sq m

Reception

Security

Admin

Meetings

Typing

Filing

Filing

Typing

Meetings

Admin

2sq m Rec

7sq m 5sq m 2sq m

Typ

SW/SE 5sq m 30sq m

Í

Í

3 phase hard dustfree

Woodwork

20sq m

Í

Í

3 phase dustfree washable fume extract

Fin, Desp

20sq m

Woodworking

Mat stor

Finishing Goods store Despatch

Goods st

Rest

Enter

GF

GF Woodwork

Í

SW/SE 6sq m

ities have been added as they came to mind. Some clients might find it easier to categorise, perhaps first listing everything to do with materials, then all the points concerning personnel and later control and service areas. It is important that every activity is included, but this does not have to be taken to extremes. As will be seen, in this case a ‘ dministration’ has a single heading. There would, of course, be organisations in which administration was a major activity, and it was necessary to list s( ay)management, document handling, post, reference and archives individually. The top of the document is broken into four major sectors: arrangement; shape; features;and remarks.

dust extract

security

35sq m

16.1

• • • •

wall

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These allow all the main requirements of suitable accommodation for each activity to be defined. Arrangement includes the following:

• •

•

•

Share with –an indication of any other activity which might share the same space. Typing and filing have been indicated as compatible here. Next to –if it is important that two activities should be closely associated, this is the place in which this is pointed out. The present chart shows a relationship between woodworking, materials storage and finishing. There will be cases, such as a viewing gallery in a demonstration theatre, where the relative levels between spaces are critical, but generally it assumed that the this can be left for resolution during design. Near to –some activities do not need to be housed in contiguous spaces, but should have convenient access from one to the other. Administration and reception are indicated as falling into this category in the chart. Floor –it may be essential that there is immediate ground floor access to an activity space (goods inward, here, for example). In some cases, psychological factors may come into play. Though there is no practical reason why people should not sleep on the ground floor, there are those who prefer not to do so, and when commissioning a house they would indicate that bedrooms must be on upper floors.

Shape may include the following:

•

• •

Aspect –the orientation of a space, which could be important to avoid direct sunlight or to maximise solar gain. Prospect, i.e. access to a particular outlook, might be a useful heading in the case of a hotel or other residential building, to allow those spaces which would benefit from access to a view to be indicated. It could also be used to identify areas which should, or should not, be overlooked from a road. Size –here quoted in terms of area, but where people rather than goods were paramount, it is frequently indicated in terms of the number of persons to be accommodated. Equipment –where all furniture and major plant and machinery can be listed. This may affect height.

Note that shape does not define proportions or geometric form in this context. Features will help to identify all those environmental parameters which make a space useable for its intended purpose, including:

•

Light –where special levels of daylighting or artificial lighting can be specified, or the fact that the point is critical can be flagged up (as is done here)for further enquiry.


• • •

Humidity –which is shown here as critical in the case of materials storage, though a specific level is not indicated. Temperature –apparently not critical in the case of this accommodation. Power supply –beyond the norm.

Some designers may wish to have minima and maxima stated for every activity, even where these fall within normally occurring limits. This avoids misunderstanding between the designer and client later. Other features which might have been included in the case of some types of building could include sound reduction within and between spaces, telephone, broadband or intranet access, or systems for the transport of documents or goods. There are also headings for the qualities needed in finishes, such as the ease of cleaning, resilience or quiet. This should not usually specify particular types of finish to be selected. If spaces need to be clinically sterilised, this must always be stated. Remarks allows any points not covered elsewhere to be noted. The space should not be used to record the subjective notes or the prejudices of the client, or indeed anything the design team are not ready to share openly with the client. The client should be supplied with a full copy of the completed chart, which forms an agreed part of the design brief. All of this refers to a very simple building. Most are more complex, and a two-level approach will be required. In such a case, individual departments are treated as units on a master chart, while detailed ones are completed for each of these. If the woodworking shop described in Figure 16.1 was part of a development for the headquarters of a firm specialising in conservation work in historic buildings, the master chart might look something like that shown in Figure 16.2. Here, the total operation has been divided into a number of sectors, representing parts of the enterprise possibly under separate sector managers. These sectors have been supposed to be:

• • • • •

management, which includes the boardroom suite, directors’ offices, dining facilities and reception; architectural salvage, where a specialised operation to collect and conserve features from demolished buildings is centred; contracts, from which ongoing work is supervised; personnel, dealing with employment issues;as well as joinery, as detailed in Figure 16.1.

Figure 16.2 shows how these departments need to relate to one another and to the outside world. This information will be provided at board level, and must take priority over the detailed departmental information provided by sector management.

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JOB NO XYZ

BRIEFING CHART

Activity

Arrangement

Public access

Architectural salvage Contracts Personnel Joinery

Shape

share next with to

near to

access

manaGF gement

level

public 1st contracts

Management

JONES AND JONES

joinery

Features

aspect size

road

equipment

Arch Salvage

Remarks

light hum- temp- power floor wall idity erature surface surface

6 people

soft

prestige parking

12 people IT

parking Í

100sqm +storage management management

DEPOT

6 people

IT

4 people

IT

150sq m

Í

hard

hard

outside storage

security

Í

Í

16.2

It will be evident that there are projects where even more layers of organisation have to be taken into account. In the case of a major hospital, there might be a master chart covering overall organisation, departmental diagrams showing how spaces were to be organised within the surgery, infectious diseases or paediatric departments, and a lower level of chart showing, within these, the detailed requirements of wards, outpatients’ clinics or staff accommodation.

Summary Whatever timescale is allowed for the preparation of a design, it must allow for the collection of information and particularly for the consultations on which meaningful briefing charts can be based. To take for granted that what has been true of an earlier project will obtain again, or that common sense will provide answers, risks finding, after much time has been expended on preparing designs, that wrong assumptions have been made and abortive work needs to be abandoned. It has to be made clear to the client that the information in the charts will be taken as the basis for the design, and that any later change will risk delay and additional design fees.

Chapter 17

Anthropometrics and ergonomics Although glasshouses and zoos are exceptions, the great majority of buildings are provided to accommodate human activity, and so it is the way in which human beings experience the spaces created within the envelope which is critical. For this reason the dimensions of those spaces are of necessity closely related to those of the human frame. Primitive buildings, which were mainly dwellings, were created for very small local populations –a single extended family, generally. They were made, for this reason, precisely to suit the minimum needs of the people who were to inhabit them. As buildings became more sophisticated, they were used by larger groups, and consideration of the statures generally found became important. This developed into a study of norms, and particularly the relationships between the sizes of body parts. Leonardo da Vinci (1452–1519)famously provided the Vitruvian Man, derived from the work of the first century BC engineer Vitruvius. Vitruvius had described the human frame in geometric terms, relating dimensions to the circle and the square, but also discovering internal harmonies between the parts, and Leonardo’s is the most famous illustration of his concept.

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In the twentieth century Le Modulor came from Le Corbusier. Le Corbusier, in particular, recognised that Fibonacci numbers a ( sequence in which any two numbers are added together to derive the next in the series;see panel below)are prevalent throughout nature, and drew attention to their occurrence in the human frame. He believed that harmonious buildings might be created if similar internal ratios were attained. In each of these cases fellow designers were reminded of the key significance of human stature, but also of the internal relationships between the sizes of body parts.

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Fibonacci numbers This concept arises from the observation of natural phenomena, such as the form of sea shells, pine cones and other forms. The series, staring from zero, runs: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34 … and is closely related to other mathematical patterns important to designers, such as the Golden Section (a rectangle formed between the diagonal and the side of a square, described in Chapter 12 as part of a discussion of aesthetic considerations) and Pascal’s triangle. 1 1 1 1 1 1

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Interest in anthropology, meanwhile, had led to great interest in the collection of comparative data, and this exploration was systematised by the anthropologist Georges Cuvier (1769–1832). Cuvier, though sometimes stigmatised as a racist because of his interest in tracing ethnic links and differences (though his was a scientific and not a pejorative interest), laid the foundations of a practical and influential design tool, which we know as anthropometry.

A n t h ro p o m e t r i c s The word ‘anthropometrics’ comes from Greek, and means ‘human measurement’. Data are collected in a strictly controlled way, so that true comparisons can be made. Careful statistical manipulation makes it possible to publish standard tables of dimensions for different cohorts and age groups, and to demonstrate the variations which may be expected within the norms. Cuvier’s intention was to derive norms, specifically so that he could examine and evaluate deviations from them. For this to have any significance, techniques of statistical analysis must be brought into play, as the concept of a norm is only useful if the variations within a population can be discerned.

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Statistics The science of statistics has developed to allow practical information to be derived from surveys of different kinds. Possibly its most important factor is the concept of the identification and evaluation of variables. In every case, it is necessary to consider the force, or magnitude of a variable, and its reliability. For example, if 90%of women but only 30%of men in a population enjoy cooking, it would be possible to infer that there was a strong correlation between gender and cooking. So far as reliability was concerned, this would depend on the size of the sample polled and to the probability of the result being replicated in a control experiment. It would exclude other cultural determining factors, such as the traditional division of roles between the genders. It is always dangerous to infer causal connections between factors. It can be demonstrated that high incidences of both telephone use and of breast cancer occur in populations –but it is unlikely that telephones cause the disease, or that the disease predisposes people to the use of the telephone. It is probably that an unconsidered factor, such as urban life, is at work. (A German researcher is said to have demonstrated a positive correlation between a falling birth rate and a reduction in the number of stork’s nests!) The statistical significance, which is a measure of the reliability of the data collected is calculated from assessments of sample size and magnitude. In the simplest terms, the larger the sample size (i n percentage terms of the entire cohort), the smaller the detected magnitude needs to be in order for it to be considered significant. To display such results, a normal distribution diagram is often used and the percentile populations which are to be ignored can be determined from it. 17.3

Since there is no such thing as an average person, whatever set of dimensions is chosen, there will be some persons who are not well fitted. Even working within the 5th–95th percentile excludes a tenth of the population. Cuvier, as an anthropologist, was interested in discovering and evaluating the ethnic differences between people inhabiting different parts of the globe, and in plotting possible relationships between them. From this, interesting probabilities about migrations could be inferred. Such data are still used in a similar way, but their usefulness in other spheres was soon recognised. Anthropometric data have, as a consequence, become much used tools in a number of further fields. They are, for example, used in the following:

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The evaluation of growth and development. Ample data have been collected over many generations, so that if weight and height measurements are taken of children at any stage, it is possible to determine whether they are making satisfactory progress. This can

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be in the form of routine screening at regular clinic visits for infants, or at longer intervals for school children. These observations allow the early identification of non-standard progress (sometimes, but not always, associated with eating disorders), so that more draconian programmes can be put in place, and treatment initiated where considered desirable. Since whole cohorts are screened, it is also possible to pick out geographical areas, or sectors of the population, where more general measures may be indicated. It is particularly useful where under-nourishment is suspected in a time of famine, so that the individuals most at risk can be helped. Monitoring the progress of medical treatment. In some medical conditions, especially those connected to endocrine deficiencies, the close observation of body measurements is a useful diagnostic tool, as well as a means of assessing the helpfulness of therapies in particular cases and in general. Establishing standard clothing sizes. A familiar sphere in which the use of standardised body sizes is most commonly encountered is that of the off-the-peg clothing industry. Manufacturers are adept at identifying the range of sizes presented by the market sector at whom they are aiming, so that the range of clothing sizes offered in shops for the young differs from that on sale where the middle aged are expected to purchase. It will also be found that the range in different parts of the same country is not identical. The design of equipment (most important for the present purpose). The design of all kinds of tools, furniture and other equipment has always, and naturally, conformed to human sizes, and it is interesting to consider the subtle differences that have been introduced because of slight changes in use. Figure 17.4 shows six examples of human drinking vessels, which have striking differences. These arise from differences in the type of liquid concerned, from the material chosen because of the drink involved, and consequently from its method of manufacture: — porcelain has been chosen for the cup and saucer, which are for hot tea, and the saucer accommodates the necessary spoon and prevents drips from spoiling clothing in a formal setting; — the blown glass is for red wine and allows for the bowl to be cupped to warm the wine, while the bouquet is collected by the tulip shape, and the plain glass displays the colour to good effect; — the tankard is used in a rough and ready setting, and so is sturdy, made of pewter and is grasped by its handle; — mugs of rougher pottery are for everyday use for hot drinks; — the cut crystal of the liqueur glass, to be held by its stem, is elegant and sophisticated;and


17.4

— easily sterilised plastic is chosen for the baby’s bottle –which is used in an inverted position. Notice, however, that every one of these objects is designed to be held securely in an adult hand. Such an interaction between use, material and situation is usually found in the design of more complicated objects. While the early anthropometrists obtained their measurements with callipers and tapes, data today are collected much more objectively, using photographs taken against calibrated screens and electronic methods, generating holographic images. The results are published in the form of tables and of diagrams for specific purposes, and standard transparent plastic mannikins with pin joints can be obtained.

S t a t i c a n t h ro p o m e t r i c s When designing ranges of clothing or equipment for the market it is acceptable to design for the population in general, and to allow customer choice to determine what is actually used. When designing for a specific clientele it is more important to be precise about the data selected, and this is especially true in the case of buildings. It is clear, for example, that the eye-lines to be considered when designing a primary school will differ from those applied to an hotel. The common measurements which are considered include the following:

•

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Eye level, standing and seated. For adults, 1,600 mm is the average standing eye-level, and 1,200 mm seated (a good level for a computer screen).These are the levels at which important warning lights will be most easily detected. It is generally considered undesirable to have any dominant horizontal line, such as a glazing bar, between or at these levels. Ceiling height. Most people would find a room where they could reach the ceiling with arm outstretched, too low. This would give 2,250 mm as a working minimum ceiling height.

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• 17.5

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Table and worktop height (Figure 17.5). The general norm for adults is 750 mm for a table and 900 mm for a worktop. One should be able to stand at a worktop and rest one’s palms easily upon it without stooping. A sink let into a worktop should not be too deep to rest ones knuckles on the base. Seat height (Figure 17.6). This is the height at which the whole length of the thigh is supported horizontally, while the feet rest flat on the floor with the lower legs vertical. 450 mm is usually adopted. Levels for electrical controls. These should be above worktop height wherever possible, and never at skirting board level unless there are imperative reasons. Reach (Figure 17.7). The normal reach of a seated adult without stretching is within a radius of 700 mm from the centre of the body. (The figures quoted above are averages, and do not necessarily conform to statutory requirements.)

For design purposes, there are two different kinds of measurement which are important:

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structural dimensions are those referred to above. The body is measured in a limited number of standard postures, and it is reasonably easy to ensure that the values obtained are accurate and consistent. However, most activities are not carried out in those stilted poses;and so functional dimensions, which indicate how a person actually sits or stands during an action, are needed. For example no-one drives a car while sitting in the pose shown in Figure 17.6, and designers

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need to consider the extent to which they slouch, stoop or reach during an operation. It must always be appreciated that such benchmark figures of necessity exclude a proportion of the population, since they are based on norms. For some purposes this is uncritical –for example a door head height must be high enough to accommodate everyone, so standard deviations can be ignored. If a seat is set at what seems to be the optimum level, however, a percentage of people will inevitably find it too low, and others too high. Many other dimensions may be required as guidelines in specific cases, and the special conditions regarding such buildings as schools, residential homes for the elderly and sports stadia will spring to mind. Special studies have been made of the requirements of people with particular disabilities, and it is only possible to refer to these here in the most general terms. Designers are referred to the organisations representing those with limited vision or hearing, wheelchair users and so on for detailed guidance. It is mandatory in the case of all public buildings that the needs of these groups are taken into account. Particular attention should be paid in each case to:

• • •

accessibility, not only to the building but to specific accommodation within it; recognition criteria, including signage, guidance on routes and location;and safety and warning provision. Special attention should be paid to emergency evacuation arrangements.

D y n a m i c a n t h ro p o m e t r i c s There are also other considerations. Static anthropometric data refer to the body at rest, and people in buildings are generally active. They need space around them in addition to that which they themselves occupy for at least two reasons:

• •

manoeuvring space;and activity space.

Many would also argue that the present age has greatly overlooked the need for ‘personal space’ –for the privacy provided by a neutral surrounding zone. We may survive on a crowded train for a short period, but would not find it a congenial environment for serious work. This, however, is a psychological rather than a spatial concept and will not be considered here.

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Manoeuvring space If a book is removed from a tightly packed shelf, it can be almost impossible to return it, without taking out most of the books. Similarly, to build a safe into a wall, a space bigger than the dimensions of the safe is needed, if it is to be slotted in. Knowledge of the exact size of the safe is not enough;one has to allow play for the actual installation, so the design of joints has to be considered.

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To design a stair well so that it is possible to take a wardrobe up without the need to dismantle it requires consideration of the three-dimensional space through which it has to pass, including corners round which it must be turned. One also has to take into account the two people who have to be present to perform the manoeuvre.

Activity space It is a common observation that a static queue waiting to enter a sport event is compact and takes up minimum space. When the gates are opened, the top of the queue begins to move long before its tail, so the queue seems to lengthen. People need more space between them when moving than when stationary. This phenomenon has to be taken into account when setting spaces aside for activities. Ten people playing five-a-side football occupy significantly more space than the same ten people drinking beer. The e ‘ nvelope of space’ varies between activities, though generally the greater the speed the larger the envelope. The high jumper in Figure 17.9 occupies a significantly larger space envelope than the onlooker.

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Ergonomics A further consideration is the amount of effort involved in the use of equipment, including the associated work space, which takes the matter into the realm of ergonomics. It is, unfortunately, common to confuse anthropometry and ergonomics, but this should be avoided. Anthropometric measurements are purely statements of dimension, even when an envelope of space surrounding the body is taken into account. Ergonomics is concerned with the efficiency of operation. Common definitions indicate that the science goes far beyond mere physical measurement to include all manner of factors concerned with the environment in which activities are set. Beyond this, again, the way in which those activities are organised also contributes to ergonomic efficiency. In practice, three components of ergonomics are identified:

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Physical ergonomics. In this area the ergonomist is concerned with all manner of physical human characteristics (including those discussed under anthropometry, above)related to physical activity. When the ergonomist designs displays and controls, perhaps in an aircraft cockpit, considers sitting or standing positions, assesses weights to be lifted or contemplates the dangers of RSI, (repetitive strain injuries), he or she is working in this field. The sizes of controls, and the angle and extension in which an arm can best support a weight, are important. The choices are deliberately made so as to limit the energy the worker must expend in carrying out routine operations, and so to minimise fatigue where possible, and to reduce the danger of injury. Some would also say that the detailed and overall planning of the physical environment and its temperature, sound levels and other characteristics fell within the remit. Physical ergonomics are also concerned with sequences of actions, and the frequency with which each occurs, as well as with the interaction of two or more people working together. Psychological ergonomics. There is an overlap between some of the factors listed above and the psychological sphere. However, beyond straightforward questions of comfort, there are matters to do with concentration, skills and memory, among other factors, which come into this area. These can be greatly affected by such choices as those of colours, sound reduction and air movement. Organisational ergonomics. Working hours, or the hierarchical structure of the management system, do not often fall within the remit of the building designer, but he or she may need to take them into account in planning. For example, housing a supervisor in an elevated, glass panelled office may set up a ‘big brother is watching you’ mindset on the floor, which may not be conducive to the best working environment.

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S o u rc e s o f i n f o r m a t i o n It would be unusual for a designer to obtain his information from original observations, though this might be necessary where the population or the activity were unusual. In such a case, if no specialist source could be identified, it would be most usual, and efficient, to employ a professional ergonomist, who would have access to specialised equipment. It would be essential to brief this specialist carefully as to what activities were to be housed and what the limiting conditions were, so that the researches could be contained within what was strictly relevant. For more general cases, it will be found that there is a wealth of sources of data, some of which are listed in the references. Care should be taken in selecting and applying the information it is proposed to use. It is important that it should be up to date, that it relate as directly as possible to the circumstances of the case under consideration, and that the statistical significance of the data (see above)is taken into account.

Summary In order to arrange the spaces within and around a building conveniently, it is necessary to appreciate the amounts of space required by the occupants for their activities. Much of this information can be found from published sources, and such data can best be applied if their origins and the purpose for which they were collected is understood. It may sometimes be necessary to collect information specifically for a particular project, in which case specialised advice should be sought.

Chapter 18

Relationships between spaces T h e c i rc u l a t i o n d i a g ra m The briefing chart provides designers with essential information, and is one of the factors which stimulate lively imaginations to begin to produce design solutions. As in every other stage of design, however, disciplined thought is needed if the optimum solution is eventually to emerge. As an important stage between receiving the spatial requirements of the client, described in the briefing chart, and moving towards a concept of an envelope to contain them, a visual aid is needed, and the circulation diagram is a powerful tool in providing this without presupposing a particular architectural form or structural system. Its neutrality in these respects allows it to be used to generate a number of alternative design solutions for comparative evaluation, as discussed in Part 3. Frank Lloyd Wright, who was very influential in his approach to the organisation of internal space from both the practical and the aesthetic points of view, seems to have pioneered the use of what he called ‘adjacency diagrams’ when designing homes in the early twentieth century. Their use resulted in the very organic plans he created, based on the needs of his clients rather than the demands of the structure. The diagram, as used today, is a development from Wright’s. His diagrams simply indicated functions, without differentiating between them. Nowadays diagrams are constructed from symbolic shapes to represent each space, and a variety of geometric forms may be employed to indicate differences of function –squares, perhaps, representing areas where privacy is important;rectangles those more generally accessible;circles indicating toilet areas, and so on.

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These symbolic shapes must be understood to have no relevance whatsoever to the eventual form or size of the spaces provided. They are drawn in relationships to one another derived from the ‘arrangement’ section of the briefing chart, with the symbols for contiguous spaces adjoining one another in the diagram, and lines linking other spaces where easy communication is required. Sometimes single lines are shown for loose links and double lines for stronger ones, but in

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either case there is no predetermination as to whether the link will be horizontal or vertical (by stair or lift)unless this has been specifically required. The lines can be conceived as elastic strands connecting the spaces. Where orientation has been specified this is indicated. The diagram shown in Figure 18.2 expresses much of the information included in the briefing chart in Figure 16.1. The functions to be accommodated in each space are stated, the heavy dotted lines show the main circulation routes between those spaces, and external access is indicated by arrows. Some notes of critical environmental considerations and of orientation have been added. It will readily be seen that this diagram does not predetermine the form that the building will take, but provides a useful guide to its necessary internal organisation. There is a trap, sometimes fallen into, of trying to arrange the elements within a simple overall rectangle or square. This should be strenuously avoided because it can subliminally suggest the nature of the eventual envelope to be produced. The diagram in this example is very simple and refers to a very simple building. In the same way that various levels of briefing chart were envisaged for a more complicated development, a hierarchy of circulation diagrams might be needed. For some common suites of accommodation, standard diagrams can be created within a practice, and some will be found in published sources. These should never be taken to override the stated preferences of the client, though they may properly be brought to his or her attention so that the client has a wide range of possibilities from which to select. Figure 18.3 shows three different ways in which the living spaces of a dwelling could be organised, indicated by circulation diagrams, while actual plans which could be generated are shown. It should be evident that these are not the only plans that could be generated from these diagrams. (It may be worthwhile to look back at the circulation diagram previously included at Figure 11.3.)

• • •

At A, a dining/recreation space with separate areas for the preparation of meals and for study are envisaged. B proposes that meals will be eaten where they are prepared, that there will be a separate recreational and entertainment space, and relegates study elsewhere in the house. C requires one large multipurpose space which can be adapted to different uses as required.

Most clients commissioning a new house would be aware of these a ( nd further)alternatives. Occasionally, families need to be helped to understand that they do not need to live in a pattern that became established because of the arrangement of their previous accommodation, but can choose –but this is unusual in the domestic setting.

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However, Figure 18.4 shows three alternative ways of arranging an office suite, again as circulation diagrams and possible plans. Not all clients would have considered each of these, and they might be pleased to have the possibilities brought to their attention. Some might have very definite views based on their experience of arrangement or on their training. The decision between them has to be taken on management grounds, and must in either case be respected.

•

• •

In arrangement A, the manager has a private space, protected by his PA’s station, but this is open to the general administrative space where all other activities are housed. The manager and his visitors have access only through this general space. In B, the PA has a separately enclosed space, too, through which the manager’s office is reached, either from the general circulation space or from the administrative area. C shows a series of separate offices, with some interconnection between them. The manager has separate access but total oversight of the remaining area.


A

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Office Office

Offices PA PA Manager

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The adoption of any one of these arrangements would presuppose specific working relationships between members of the department, and so has to be a matter for conscious choice. It may be necessary to produce a number of sketch diagrams before one which is considered reliable is finalised. This creates a danger that the temptation to turn the diagram into a plan will be hard to resist. It is very important that the final diagram, which is agreed with the client, remains as abstract as the first, if the freedom to design innovatively is to be preserved. It may be necessary to explain the nature of the diagram to the client, so that the client does not receive the false impression that he or she is inspecting and approving an actual plan. The principles to be borne in mind in preparing circulation diagrams include:

• •

avoid choosing symbols that could be taken to indicate the shape or size of the room that will be planned; select varied symbols to denote different kinds of accommodation;

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do not try to make the whole diagram fit into a rectangle or any other geometric shape, which might be mistaken for the preferred shape of the final building; differentiate between levels of connection between spaces: at the least, show interconnected areas, contiguous areas and adjacent areas differently; do not differentiate between physical levels unless this is mandatory;and agree the final version of the diagram with the client, and ensure the client understands that it will be one of the bases for future design work.

Relationships between spaces The circulation diagram is a very useful tool when a designer needs to determine necessary practical relationships between spaces, but there are other considerations. Space is three dimensional, while the charts are almost inevitably limited to showing only two. Since variations in the height of spaces, and between related floor levels, affect the three-dimensional form of the building, the need for such changes has to be assessed during the briefing process.

The third dimension The functional reasons for which two-dimensional thinking has to be disciplined might include a need for additional headroom or the accommodation of eyelines, while questions of proportion and scale may be relevant. Additionally, the provision of service ducts, or the nature of the structure adopted, often influence decisions.

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Headroom greater than the usual floor to ceiling height might be needed to accommodate: — sporting activities, such as basketball, when the advice of the sporting body concerned must be taken; — the size of equipment, in which cases not only the dimensions of the plant, but its installation, need to be taken into account; — access to natural lighting, perhaps through a clerestory; — the circulation of air;and — internal acoustic design, as within a concert hall or lecture theatre. Uninterrupted eyelines are needed in many large spaces, and may force the use of: — raised platforms or podia; — raked or stepped floor;and — galleries.


All of these factors are functional requirements of a building that is to serve its purpose of enclosing useful space and they have to be considered along with the two-dimensional arrangement of spaces on one level. In other words, the space within the building must be considered in three-dimensional terms, and not simply as the function of so many square metres of floor area. The section is of equal importance with the plan. Other factors which may affect the nature of the three-dimensional space to be provided include:

• • • • • •

interaction with the development of the structural form of the building; a statement of function to be made in the urban landscape; aesthetic and psychological effects may make a room height that would be acceptable from a practical viewpoint, visually unpleasant; massing –the external articulation of a building as an architectural artefact; service ducts can sometimes be accommodated conveniently above false ceilings, with inevitable changes in room height;and structural systems may be recommended on grounds of economy, speed of construction or for other reasons, and result in a roof line which causes variations in ceiling height.

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In virtually every case an attempt should generally be made to resolve the spatial problem set by the functional requirements of the client before such further factors are taken into account. However, this latter group of influences is not unimportant. Their interactions may be difficult to resolve but ultimately found to provide creative opportunities.

It may be helpful to consider some examples of designs where factors beyond the merely practical have been given importance. The Guggenheim Museum, New York (Frank Lloyd Wright, 1959). This art gallery is conceived as a helical ramp circling the internal walls of a drum (which widens as it rises). The visitor usually takes a lift to the top of the ramp, and descends gradually, viewing the exhibition on the way. The central area may be used to display large sculptural pieces. Side galleries and offices are passed on the way. Walking the gallery is a fascinating experience in itself, but the ramp has limitations where its core purpose is concerned. It is excellent for the display of a well-sequenced collection of small works. However, it is difficult to retrace one’s steps, and one cannot step back to view an exhibit from a distance, or pause too long without impeding fellow visitors.

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As a sculptural piece, the building is stunning. It is an iconic example of a building designed from the inside out. And where important threedimensional work is displayed centrally, wonderful viewing opportunities from a multitude of viewpoints are afforded.

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The Lloyds Building, Lime Street, London (Richard Rogers, 1986). Here, a series of galleries has been arranged around a traditional trading floor, and the sense of a large number of small enterprises acting in collaboration is effectively reinforced. At the time of building, it was important that the privacy as well as the integrity of the separate syndicates was preserved, while allowing close interaction between them, and the arrangement of the building facilitated this. Nowadays, most trading takes place electronically, but it is reported that the corporate sense of the building remains unimpaired. St John the Baptist Church, Ermine, Lincoln, (Sam Scorer, 1963). The requirement here was to provide a large, unimpeded space which could be used in a variety of ways. This was achieved by the central siting of the sanctuary with ramped seating arranged around three sides.

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It is reported that the roof form, while capable of providing a well-lit, unimpeded space, was largely chosen for the visual impact it would make on the neighbourhood. The building has proved hard to adapt to modern needs, but the community has found it possible to make the compromises necessary to continue to use it effectively.

Each of these buildings demonstrates three-dimensional thinking, and in each case factors beyond the purely practical have come into play –internal sculpture at the Guggenheim, expression of corporate organisation at Lloyds and a desire for external statement at Ermine. In each of these cases there were sound practical reasons for thinking three dimensionally, quite apart from the organic expression of their purposes. None could have been conceived simply as a plan or a series of plans. The section had to be carefully considered as well. They also give interesting clues to the compromises which are inevitable when competing needs have to be juggled to produce a practical plan.

T h e o p t i m u m a r ra n g e m e n t As has been said, the priority will generally be to provide space that is as well arranged to suit the convenience of the occupants as possible. While other factors will be taken into account during the iterative process of design, and compromises may be necessary, it is imperative that a workmanlike arrangement of space should be sought initially. To generate a potential plan from the information collected through the briefing process, and the circulation diagram in particular, it is help-


ful to have a number of formal strategies available. It will be found in practice that these are more likely to produce workable solutions than the mythical ‘sketch on the back of an envelope’.

Modular squares A common practice when generating plans of multi-cellular buildings, especially where there are no significant level changes to consider, is to work on a modular grid. As a spin-off from the modular co-ordination movement, this grid is usually either a metre square (for domestic work, a 900 mm one is often chosen). Sometimes hexagonal or even triangular grids have been used (a practice popularised by Frank Lloyd Wright), but the limitations of geometry make the adoption of more intricate tessellations impractical for most purposes.

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The floor space required for each activity is assessed in terms of a number of modules, and rectangles containing those areas are drawn. These are then arranged, in the relationships derived from the circulation diagram, on a squared grid without any attempt at the early stage to arrange them within a particular perimeter shape. If the sketches are drawn on tracing paper laid over a grid, a large number of possibilities can be produced in a short time. Most of these will be discarded, but a few will be seen to be worth further consideration and adjustment. This system works particularly well for simple buildings, such as branch libraries, nursery schools or single houses, where it can be very helpful in breaking away from familiar solutions. Its usefulness is occasionally found to break down if non-rectangular shapes are actually needed, though the fact that only rectangles are used in this stage of the procedure need not limit the shapes of the final spaces designed.

Planning grid Where a large number of similar spaces is required, as might be the case with a hotel block or a commercial building, it may be more helpful to consider a larger planning unit, which might eventually be related to the structural system adopted. Usually, this means that small repeated suites, such as en suite hotel rooms, or office/secretary groups, are considered as units in planning, rather than the separate spaces, so there are two stages of planning involved –first the suite, then the block. Effectively, use of this strategy means that the repetitive feature is allowed to dictate the planning grid, so that larger and smaller spaces might have to be uneconomically larger than would otherwise be necessary. The effect of this could be catastrophic, for example, in cases where income depends on the economic use of floor area. For this reason great care in selecting an appropriate grid is needed.

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One way to obviate this problem, where the site allows, is to articulate the building so that separate wings house different kinds of accommodation, separately planned. In this case, the kind of device described under ‘building blocks’ below might have to be brought into play.

Organic design The solution proposed above, planning separate kinds of accommodation individually before assembling them as a whole, can be derived much more directly from the circulation diagram (and this was Lloyd Wright’s procedure). This results in a fully articulated building, where the purposes of the parts are clearly evident to the passer-by, and this is typical of much mid-twentieth century design.

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The trap is that a designer may be tempted to simply ‘b uild walls round’ the circulation diagram, without going through the intellectual process of considering options. It is best to dismember the whole into components, to work on each individually, and then to reassemble them in accordance with the overall requirements of the diagram. To achieve this means going back to the original diagram to analyse it, so as to identify the major controlling pattern and its minor parts. It is then necessary to develop a coherent internal organisation for each of the various components, before attempting their assembly.

Section The designs for some buildings are best developed from the section rather than the plan. There are two groups of cases where this might apply.

Internal relationships First, there are buildings where the relative internal levels, either of floor or of ceiling height, are critical. Examples might include:

• 18.13

•

a lecture theatre, needing good views for demonstrations and projection, and where acoustics for speech are paramount;and a leisure centre with gym and indoor games areas as well as social and changing facilities.

Th e c o n t o u r s Where the site dictates changes of floor level, it is essential to start from a full understanding of the contours. Changing floor levels may be required either in order to exploit the advantages of a situation or to minimise the expense of cut and fill or of elaborate structures to obviate the slope.

•

Where there are fine views, so that spaces higher up the hillside can have views over the roofs of those below, such sites can be


•

exploited to great advantage, provided a sensible balance is maintained between the accommodation and the levels. In cases where very complicated internal circulation is required, floor levels can be gently modulated so that close relationships are established between a larger number of spaces than is possible where all floors are on one level. 18.14

Building blocks Where spaces of varied heights have to be grouped, it can be helpful to work with a three-dimensional model. This may be found to be appropriate, in particular, where:

• •

there is a very isolated site, so that a building will be seen from many points of view;or where a ‘statement’ building (a national monument, say)is being considered, a fully three-dimensional concept needs to be sought from the outset.

In such cases, to resort to the use of physical blocks, analogous to children’s building blocks, may be found useful. (This does not have to be expensive or elaborate at the development stage –it is amazing what can be done with books and other objects that come readily to hand!) This will usually go alongside the application of other techniques to aid the visualisation of possible outcomes.

Summary From what is indicated above, it will be clear that it may be helpful to move between more than one of these strategies to generate ideas. Whilst it is conceivable that any of the strategies referred to might be computer assisted, it is still more usual for them to be paper and pencil operations. Often, they can usefully be related to brainstorming techniques, referred to in Chapter 10. It should be assumed that the materials generated are purely for personal use, and are disposable. If the crude outcomes of any of them are prepared so as to look like finished drawings, they will deceive. They are a stage of development, not its end product. Where practitioners are asked to provide outline proposals for discussion and eventual development, they should certainly be able to demonstrate that they have followed the potentially most fruitful path. They must also show that a variety of solutions is possible and what the advantages and problems with each might be.

18.15

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Part 4

Bibliography Building Regulations 2006. Croney, John (1980) Anthropometry for Designers. London: Batsford. Edwards, Michael (ed.) Journal of Planning and Environment Law. London: Sweet and Maxwell (current edition). Grandjean, Etienne (1988) Fitting the Task to the Man. London: Taylor and Francis. Jackson, Alan A. (1991) Semi-detached London. New York: Wall Street Publications. Mitchell, William J.J. (1990) The Logic of Architecture. Cambridge, Mass: MIT Press. Pheasant, Stephen (1996) Body Space. London: Taylor and Francis. Royal Institute of British Architects Product Selector: Part 2. London: RIBA (current edition). Sanders, Mark S. and McCormack, Ernest J. (1993) Human Factors in Engineering and Design. New York and London: McGraw Hill.

Webliography www.architecture.com/go/Architecture/Reference/Library_898.html (22 August 2005) www.bre.co.uk (Building Research Establishment) (22 August 2005) www.compactlaw.co.uk (22 August 2005) www.dh.gov.uk (Department of Health) (22 August 2005)

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www.lecorbusier.com (22 August 2005) www.productselector.co.uk (CI/SfB) (22 August 2005) www.propertylawuk.net (22 August 2005) www.ergo.human.cornell.edu (anthropometrics) (22 August 2005)

Part 5 Environmental design INTRODUCTION, 195 Chapter 19

PRINCIPLES OF ENVIRONMENTAL DESIGN, 197 Introduction, 197 Human comfort, 198 Thermal energy and comfort, 198 Air quality, 207 Light and visual comfort, 209 Aural comfort, 210 Sustainability in design, 211 Design process: open versus closed, 212

Chapter 20

DESIGN STRATEGIES, 215 Introduction, 215 Low energy strategies, 215 Solar energy and design, 222 Ventilation, 228 Daylight, 231 Sound insulation, 234

Chapter 21

CASE STUDIES, 239 A house on an urban site, 239 A research station in Antarctica, 242 A retail centre in suburbia, 245 BIBLIOGRAPHY, 249

Part 5

Introduction

The use of the term e‘ nvironmental control’ is rife in the literature associated with the design and technology of buildings. The use of such terminology is more akin to the engineers’ attempt to describe mechanical and electrical systems for providing some form of environmental comfort. From a design philosophy standpoint, successful design should work with the environment and not against it. To quote Rachel Carson after Wines (2000), ‘The control of nature is a phrase conceived in arrogance, born in the Neanderthal age of biology and the convenience of Man’. This Part will deal with various aspects of building physics that relate to the environmental conditions in and around buildings. It will present the basic principles that explain the behaviour of the building enclosure in its immediate surroundings. It will also demonstrate how the design process can make use of these principles to create comfortable and pleasant surroundings without excessive impact on the environment. The Part is organised into three chapters. Chapter 19 will explain the various principles behind the behaviour of the natural environment (heat light air, etc.)and the response of both humans and their buildings to it. An appreciation of such principles is needed if a sustainable design approach is to be encouraged. Chapter 20 will demonstrate how the basic physical principles described in the previous chapter can be translated into design strategies. The discussion of the various design strategies will seek to demonstrate the relationship between the various aspects of performance that a welldesigned building ought to have. The emphasis throughout the chapter is on low energy design strategies. The chapter will endeavour to help the reader develop an appreciation for a holistic approach to design, and

196

E N V I R O N M E N TA L D E S I G N

an awareness of some environmental and technological issues and ways on how these can be integrated into the design activity. In Chapter 21 a series of case studies will be presented and discussed. These will provide the reader with evidence on how the principles explained and demonstrated previously can be integrated into design approaches, culminating in buildings that offer comfort and user satisfaction without excessive environmental penalties.

Chapter 19

Principles of environmental design Buildings are designed and built to provide shelter and comfort. This chapter will attempt to introduce various environmental factors that help describe the level of comfort experienced by occupants. The material presented in this chapter will enable the reader to:

• • • • • •

appreciate the factors that affect human comfort; familiarise themselves with the terminology of environmental physics; understand the links between the various environmental factors and human comfort; appreciate the relationship between environment, comfort and resources used to produce the built environment; gain some introductory knowledge of design targets for the various environmental aspects;and appreciate the holistic nature of the design process.

I n t ro d u c t i o n We design, construct and maintain buildings so that humans can carry out their activities in a suitable environment that provides shelter, safety and comfort. The shell of the building, or building fabric, plays a key role in creating the right conditions of comfort and safety inside buildings. It acts as a moderator of climate and a barrier to extreme climatic conditions. The way the building fabric is designed and built will determine how much comfort is achievable inside buildings and how much energy is used to achieve it. A sustainable design approach must make it a priority to reduce the excessive use of energy to provide comfortable conditions inside buildings. This can be achieved by means of careful consideration of the building shell when designing buildings. Before the

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design of the building fabric is discussed, it is necessary to consider the various aspects associated with comfort inside buildings.

Human comfort Comfort is a complex issue that covers the environmental conditions, the way humans perceive their environment and the level of control they can exercise over the conditions in the environment. The challenge for designers and other building professionals is to produce a built environment that is comfortable and sustainable in terms of resources use and waste production. Comfort, in this context, refers to an environment free from discomfort and stress due to the various physical factors that describe the environmental conditions experienced and perceived by the occupants. In this chapter, the discussion will be restricted to the environmental aspects of comfort. These include the thermal environment, the visual/lighting conditions, the aural environment (sound/noise conditions)and the air quality.

Thermal energy and comfort ‘Hot’ and ‘cold’ are words that are often associated with an attempt to describe the immediate environment around us. Heat is a form of energy, often referred to as thermal energy. A room, for example, is described as thermally comfortable when there is a certain balance between the heat in the environment and that generated by the body of the occupant s( ee Figure 19.1). In this section, the thermal properties of building materials and the way these affect thermal comfort will be discussed.

Temperature Temperature is a measure of the intensity of heat content. The unit for temperature is the degree Celsius (ºC)as described in the international

19.1

P R I N C I P L E S O F E N V I R O N M E N TA L D E S I G N

system of units. The Celsius temperature scale uses the melting point of ice as 0ºC and the boiling point of water as 100ºC. In everyday applications, air temperature is used to describe how hot or cold the environment around us is. The inside air temperature is the average temperature of air in the room measured with a dry-bulb thermometer, which is often referred to as the dry-bulb temperature. Air temperature inside a room affects the level of thermal comfort. An extreme example of this is when you enter a greenhouse on a hot sunny summer day;you will feel the ‘hotness’ of the environment straightaway. The opposite is also true for cold temperatures. Another type of temperature, which you may come across, is the mean radiant temperature (MRT). This temperature, inside a room, depends on the presence of radiating surfaces in the room, such as the hot surfaces of radiators and the runs of hot water pipes. The MRT can be considered as the average temperature of the various surfaces in a room.

Human response The human body has a control mechanism that keeps a core body temperature around 37ºC. As a by-product of our metabolism system, heat is generated at a rate ranging from 100 W at rest to about 1,000 W at high levels of physical activity. Thermal comfort, for the human body, is affected by the balance between the heat gains (due to metabolism) and heat losses from the body to the environment. Heat exchange between the human body and its surroundings is by the three basic processes described later. Furthermore, the body can lose heat by the evaporation of sweat. Conduction heat exchange is rare since direct contact between the skin and any surrounding surfaces is negligible. The breakdown of the heat loss mechanism is about 20% by evaporation, 35% by convection and 45% by radiation (see Figure 19.2).

19.2

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200


These components are controlled by a number of environmental parameters. These are, respectively:

• • •

humidity and air movement; air temperature and air movement;and MRT (which takes into account the heat exchange between the various surfaces in the room and the air).

To provide comfort, the conditions inside buildings should be maintained at fairly constant levels. To achieve this objective in a sustainable way, it is arguable that the use of fossil-fuel based energy for heating or cooling should be minimised and the use of renewable energy sources should be encouraged. One way of reducing the need for heating and cooling is to consider the design of the building fabric carefully. The following areas are of particular relevance if conflict between passive/low energy design strategies and comfort is to be avoided:

• • •

the provision of heating should avoid underestimating the load during the pre-heating period. It should also avoid overestimating the load by not accounting properly for the activity level and clothing; discomfort due to local radiant heat loss and down-draught should be avoided. This can be dealt with through attention to room layout, glazing materials and positioning of heat emitters;and account for solar overheating and use shading devices and ventilation strategies that maximise the thermal benefits and do not compromise daylight.

Thermal behaviour of buildings A building is made up of a number of materials. Each of these has its unique physical properties relating to the flow of heat. The overall thermal performance of a building is the result of the individual performances of its constituent components. An important part of the design and construction processes is the selection of appropriate materials. The primary objective of such selection is to achieve a building with an enclosure that is capable of performing as much of the climate moderation as possible without the use of energy intensive processes such as heating and cooling systems. Such an enclosure would offer economic, environmental and psychological benefits. Before a full discussion of the thermal properties of materials is undertaken, it is necessary to consider the three basic mechanisms of heat transfer. Radiation is the transfer of heat by means of straight-line flow of electromagnetic waves through space or air. All bodies (materials) emit or absorb radiant heat depending on the nature and temperature of their surfaces. Dull, black materials have the highest absorption and emission of radiant heat. Shiny, silver surfaces have the lowest capability to absorb and emit radiant heat. Solar radiation is the most obvi-


ous source of radiation examples around. A person’s skin is warmed up by radiation if it is exposed to the sun or if he or she stands near a fire. A sensation of cool would be felt if a person stands near a cold surface (window surface) or under a clear night sky. Objects inside a heated room will exchange heat by radiation between themselves and the cooler surfaces, such as the internal faces of glazing. Conduction is a process in which heat is passed through a solid material by moving from hotter molecules to cooler ones. The material remains stable while the heat moves on. The rate at which heat is passed from one side of the material to another depends on its thermal properties. Convection is the transfer of heat by means of a moving stream of air or water (usually known as fluid). Unlike conduction, this process involves the movement of particles that make up the material. A typical example of convection would be the warming up of air in a room heated by a gas convector heater.

Radiation All objects give off heat and receive it from surrounding objects by means of infra-red electromagnetic radiation. In this process, the thermal energy of the atoms on the surface of a material generate electromagnetic waves that carry the heat to any surrounding surfaces at a lower temperature. These rays form an invisible part of the light spectrum and behave in the same way as light, as they travel in straight lines at a speed of 3 x 108 m/s in vacuum. If two objects see each other through a transparent medium, they will exchange radiant energy at a rate proportional to the difference between the fourth powers of their absolute temperatures. The radiative properties of building materials are important to the design process as they determine the behaviour of these materials towards heat gain and loss by radiation. When incoming radiation hits the surface of an object, some of it will bounce off and will not change the temperature of that material. This is determined by the materials’ reflectance. The other part of the incoming radiation will be absorbed by the material according to its absorptivity and will raise its temperature. The sum of the reflectance and absorptivity for a given material is always one. The ability of a material to give off radiation is dependent on its emissivity. The ability of materials to deal with radiation depends on the wavelength of radiated energy. Solar radiation is emitted as short wave radiation while thermal radiation from terrestrial sources, such as sun warmed building surfaces, is emitted at longer wavelengths. The data in Table 19.1 show the radiative properties of some typical materials. To illustrate the way buildings deal with thermal radiation, the following example will be explored. A building painted white will reflect

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Table 19.1: Average values for radiative properties of some materials and finishes (based on data from CIBSE Guide A) Material Aluminium Asphalt Steel Brick Tiles Concrete Stone

polished dull block stainless light dark red/brown block limestone sandstone

Absorptivity

Emissivity

0.25 0.5 0.87 0.2 0.49 0.76 0.64 0.63 0.43 0.65

0.045 0.24 0.94 0.085 0.9 0.9 0.9 0.94 0.92 0.92

around 80% of the sun’s direct thermal radiation, while it will reflect only about 10% of the radiation received from other sun heated surfaces (pavements, other buildings etc.). If the building was clad in a bright, metallic exterior finish it would offer better protection from both solar radiation and terrestrial re-radiation, as its reflectance is around 95% for both types of radiation. Given the low emissivity of polished metals, these re-radiate less heat to the outside during the cold season. This means extra weather protection of these materials compared to white painted finishes. The effect of low emissivity of metals can be exploited in building construction by combining it with an air space, such as the case of aluminium foil in cavities.

Conduction When choosing materials for a building, one of the criteria used for selection would be the building’s ability to provide comfort without excessive use of energy. Under these conditions, the use of materials with good insulating values is usually the preferred option. The resistance of a material to the conduction of heat is an important indicator of its thermal performance and a measure of its insulating value. The higher the resistance of a material the better its performance is. Sometimes in the literature materials are specified by their conductivity (r ate of conduction heat transfer across a thickness of 1 m of material for a temperature difference of 1 degree K and a surface area of 1 m 2, W/m K). For any given material, the resistance is derived from its thickness, in metres, divided by its conductivity. For a given thickness, low conductivity materials have high resistance values.


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Building materials have varying conductivities. Metals have very high conductivity (as they are good conductors of heat). Masonry materials and glass tend to have moderately high conductivity given their high densities. Wood, on the other hand, has a moderately low conductivity. When higher levels of insulation are required to be used in the building fabric, light weight insulating materials with very low conductivity values are used. These normally consist of fibrous structures enclosing pockets of air. Air is a good insulator, provided that its movement due to convection is restricted. This is usually achieved by enclosing small air-filled cavities within the structure of the material. Table 19.2 gives some thermal conductivity values for a selection of materials.

Table 19.2: Thermal conductivity values for a selection of materials (based on data from CIBSE Guide A) Material Brickwork Clay tiles Cement mortar, dry Plaster Plasterboard Concrete blocks

Cast concrete

Stone

Cork

Straw

Thermal conductivity (W/mK) inner leaf outer leaf

lightweight medium weight heavyweight dense dense reinforced aerated limestone sandstone slate board expanded, impregnated tiles board thatch

Glass fibre Softwoods Timber flooring Chipboard flooring blocks Plywood Glass Aluminium Polyvinylchloride (PVC) Glass fibre, quilt Glass wool Mineral fibre, blanket Polyurethane, expanded

0.62 0.84 0.85 0.93 0.22 0.16 0.22– 0.27 0.32– 0.54 0.73– 0.9 1.7 1.9 0.16 1.5 1.83 1.44 0.04 0.043 0.08 0.057 0.07 0.036 0.12 0.14 0.14 0.15 1.05 230 0.16 0.04 0.033 0.032 0.023

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Table 19.3: Heat storage properties for a selection of building materials (adapted from CIBSE Guide A) Material

Brickwork Brick mud Cement/lime plaster Plaster Ceramic floor tiles Concrete blocks, lightweight medium weight heavyweight Plasterboard Polystyrene, expanded Polyurethane board Rock wool Mineral fibre, blanket

Density, ρ(kg/m3)

Specific heat, c (kJ/kg K)

Volumetric specific heat capacity, ρ x c

1,700 1,730 1,640 800 1,700

0.80 0.88 0.84 0.84 0.85

1,360 1,522 1,378 672 1,445

750– 950 1,050– 1,550 1,850– 2,050 950 23 24 23 48

0.84 0.84 0.84 0.84 1.47 1.59 0.71 0.71

630– 798 882– 1,302 1,554– 1,722 798 33.8 38.2 16.3 34

Thermal mass Apart from presenting some resistance to heat flow, building materials are sometimes required to perform another role in controlling the thermal environment inside buildings. Each material has a capacity to store heat, also referred to as thermal mass. This is given as the product of the material’s specific heat capacity, its mass and the increase in its temperature. The specific heat capacity is the amount of heat a material will store per unit mass and per unit of temperature change. The effect of the thermal mass thermal is quantified by the ‘admittance’, which is a property of a building component (such as a wall or a floor). The higher the admittance the more heat is stored in the component and the longer for the building to respond to temperature changes, both internal and external. Further explanation of the usefulness of thermal mass will be given in Chapter 20, Design strategies. Table 19.3 gives some heat storage properties for a selection of building materials.

Humidity Humidity is caused by the presence of moisture in the air. Relative humidity (RH)is a measure of the actual amount of water vapour present in the air compared to the maximum that air can carry under the same conditions of temperature. RH affects the ability of the human body to cool itself by perspiration. The higher the RH the more difficult for the body


to secrete sweat. High humidity and low temperature can cause the air to feel chilly. Low humidity can cause dryness of the throat and skin. The presence of water in and around buildings affects the relative humidity and hence the level of thermal comfort. Furthermore, if it is not controlled properly, it can lead to condensation, which in turn affects both human health and the building fabric. Condensation is a term used to refer to dampness caused by a change of state from water vapour to water when certain conditions allow that to happen. The continuous improvement in thermal insulation standards can lead to this type of problem if ventilation and other measures are not properly considered.

Condensation Basic principles Water vapour is a natural occurrence. As water evaporates from the vast expanses of oceans, water vapour is added to the air. Its presence in the air amounts to around 5% by weight. In enclosed spaces, such as the inside of buildings, the humidity in the air increases due to the various processes that take place (cooking, washing and so on). This can lead to the discomfort of occupants and to condensation. When warm, humid air encounters a cold surface, some of the water vapour in the air will condense as droplets of water on the cold surface. As a rule, water vapour in the air condenses on a surface if the temperature of that surface is below the dew point temperature of air. This point is illustrated in the example in Figure 19.3. In practice, we

19.3

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19.4

would know the air temperature and its relative humidity as part of the design data. We could determine surface and structural temperatures and use them with a psychrometric chart to check for possible risks of condensation. Various parts of a building where sudden temperature changes are likely to happen are susceptible to condensation. These are found mainly on the cold side of insulating layers and around cold bridges. The problem can be made worse if these areas are not properly ventilated (see Figure 19.4). A typical example of such a case would be the roof in an existing dwelling that has been refurbished and an insulating layer has been introduced into the roof space. Before the introduction of insulation, the movement of both heat and water vapour from inside to outside is gradual and the air never reaches its dew point temperature. After introducing insulation, a large temperature drop will occur between the two sides of insulation. Therefore the water vapour diffused through the insulation will reach colder surfaces and condenses into water. Ventilating the roof space can rectify the problem. For further details on how condensation is checked for and the measures taken to prevent it the reader is referred to Volume 2 in this series, Environment, Technology and Sustainability.


Air quality The level of satisfaction with the environmental conditions inside a building is affected by the indoor air quality. Poor air quality is thought to be a contributing factor to sick building syndrome (a n ailment thought to be connected to the air pollution inside the home or workplace). The presence of pollutants in the indoor air, if allowed to exceed certain levels, will reduce the quality of air. Such pollutants are either generated internally, as in the case of furnishing and equipment vapours and gases, or are carried inside with the air from outside, as in the case of traffic fumes. To create healthy and comfortable environmental conditions inside our buildings we need fresh air at the correct temperature with the right moisture content and free from pollutants. This role is fulfilled by the ventilation system which can be natural, mechanical or some combination of both.

Ventilation The main two reasons for ventilating buildings are: the need to provide fresh air for health reasons and the desire to create comfortable conditions with minimal use of energy. A design process that strives to create a sustainable built environment needs to strike a balance between the following two aspects of performance:

• •

the thermal performance of the building fabric and the careful selection of heating, cooling and lighting techniques;and an indoor climate that has acceptable standards in terms of comfort, ventilation effectiveness and air quality.

When the purpose of ventilating is to provide fresh air for health, the quantities required vary depending on the conditions in the room. For breathing, we need little fresh air (a round 0.3 litres per second per person). For comfort, however, we need much more. To remove carbon dioxide and body odours, we need to supply 30 times as much as the basic requirements. The presence of heavy smoking will raise the ventilation requirements to 100 times as much as the basic rate (s ee Figure 19.5). Introducing outside air into the building can lead to excessive heat loss. This is particularly a problem in winter and when the air movement in and out of the building is not controlled properly. Ventilation can be used, under certain conditions, as a means of cooling buildings without the excessive use of energy intensive mechanical services. This is mainly true for hot climates, but it can also be used in the UK during summer months. Its success depends on the presence of thermal mass and shading devices. These design features will be discussed in more detail in the forthcoming sections.

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19.5

The provision of natural ventilation, which in itself is desirable, can lead to other ‘design conflicts’ that need to be addressed. In winter, for instance, the air that flows into and out of the building needs to be controlled adequately to reduce infiltration heat loss. In summer, for ventilation to be effective, outside air needs to be at a temperature lower than that of the inside (night-time cooling).

Indoor air quality The quality of the air inside buildings is affected by both the air quality outdoors and the indoor pollutants. Outdoor pollutants such as oxides of sulphur (SOX )and nitrogen (NOX )cause acid rain which, in turn, causes acidification of water streams, damage to plants and degradation of stonework in buildings. With regard to human health, there is a growing concern about the effects of air pollution. Particulate matter of diameter 10 µm and less (PM10)is thought to be behind cardiovascular and respiratory diseases. Indoor pollutants include carbon dioxide, radon, formaldehyde, sulphur dioxide, mineral fibres, tobacco smoke, body odours and several other substances. There are, as yet, no acceptable limits for these pollutants but this does not prevent us from reducing them. The best approach is to reduce pollutants at source. Failing that, they can be filtered out. This latter process tends to be energy intensive. Since the built environment is responsible for a large proportion of energy use, careful design can lead to a reduction in external pollution by producing buildings that are energy efficient. With regard to internal pollutants, again designers can play a major role in their reduction.

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This can be achieved by specifying materials that give off less pollutants and provide adequate ventilation rates for health and comfort without an excessive demand for energy use.

Light and visual comfort Light is a form of energy that is necessary for the everyday existence of our environment. It represents the visible part of the electromagnetic spectrum covering a range of wavelengths from 400 to 760 nanometres (10 -9 m). The level of light is measured using a unit called the lux. The human eye is sensitive to a wide range of light levels from 100,000 lux in bright sunlight to 0.2 lux in bright moonlight. While our eyes can register information over such a wide range of light levels, the amount and contents of information we register is directly proportional to the level of light. A young person with good eyesight can probably read a theatre programme under 10 lux. This, however, would cause some eyestrain if it is to be repeated regularly. When designing buildings, light, whether it be from daylight or electric lighting, needs to be provided to the levels required for the safe and comfortable use of the building. Different spaces or functions would require different lighting levels. A hallway would require 50 lux while an office interior would require 400–500 lux.

Table 19.4: Daylight factor values for typical interiors (from http://home.wlv.ac.uk/~in6840/Daylightfactor.htm) Building type

Dwellings Schools and colleges Offices and banks

Drawing offices Assembly and concert halls Libraries Art galleries and museums Sports halls

Location

Daylight factor

Living rooms o ( ver depth, but for minimum area 8 m 2) Assembly and teaching areas Art rooms General offices, counters, accounting book areas, public areas Typing tables, business machines, manually operated computers General Drawing boards Foyers, auditoriums, stairs o ( n treads) Corridors (on floors) Shelves o ( n vertical surfaces of book spines), reading tables On pictures b ( ut special provision for conservation where required) General

1% 2% 4% 2% 4% 2% 6% 1% 0.5% 1% 6% 2%

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Daylight is generally preferred to electric lighting. Most people prefer to live and work in day-lit spaces. The reasons for this seem to be aesthetic, psychological and practical. Daylight levels are specified in terms of ‘Daylight Factor’ or (DF)values rather than an absolute illuminance level in lux. Table 19.4 gives an indication of the DF values used in design. Further discussion of the topic will be covered in Chapter 20. Daylight should not be confused with direct sunlight which should be excluded from internal spaces whenever possible. The availability of daylight inside a building depends on the window characteristics (size, glazing, position in the wall, etc.)as well as the internal surface colours. Light surfaces increase the amount of daylight as reflections from surfaces will increase the direct light coming from the sky vault.

A u ra l c o m f o r t Sound plays a major role in our personal lives and the way we appreciate our environment. Areas such as noise control and architectural acoustics have an effect on the way we utilise our built environment and the level of comfort we perceive.

Sound insulation Unwanted sound is perceived as nuisance and can have detrimental effects, such as annoyance and sleep disturbance, and because of these problems, this topic area is presenting designers and building professionals with more challenges than ever before for two reasons:

•

•

Given the high level of machine dependency that modern societies have, the noise level from various activities is on the increase. If you add to this the continuous increase in environmental awareness among the general population, you can see why such an issue is becoming topical. National surveys have shown that more than half the population are exposed to daytime noise levels that exceed the World Health Organisation (WHO)ratings for significant community annoyance. To deal with these problems, the design process must engage with the issue of sound insulation, noise reduction and its control. This is done by careful consideration of the building fabric and the planning of both internal spaces and external surroundings.

Sound insulation refers to the methods used to minimise sound intrusion into a space and reduce its level. Sound or noise is a sensation in the ear and brain caused by variations in the air pressure affecting the ear drum. It is measured in decibels (dB). This is about the smallest change in sound level that an average human ear can detect. The range of noise levels over which the human ear normally operates varies from the hearing threshold of 0 dB to the threshold


of pain at 140 dB. In order to provide comfortable conditions inside buildings, noise levels should be kept to within a smaller range. This varies from 30 dB for a quiet room to 70 dB for a busy open plan office. Different types of buildings and activities would require different design standards.

Room acoustics Another sound-related area which building design is concerned with is the quality of sound in enclosed spaces, generally known as acoustics. This is particularly important in buildings such as auditoria and classrooms where the sound quality heard by the audience will determine the level of success of the performance. For such enclosed spaces, the design seeks to create an acoustic environment where echoing is minimised. Such conditions are achievable by using absorbing materials as internal finishes, combined with suitable shapes and volumes. One of the performance indicators in this case is the reverberation time (in seconds). This is the time taken for a sound to decay by 60 dB after its source has stopped. Such a time gives a good indication of the level of echoing in a room. Different types of buildings require different reverberation times. Details on design targets and the ways they can be achieved will be given further coverage in Volume 2, Environment, Technology and Sustainability.

Sustainability in design Built environment, as a design product, is different to many other products. It is more than just a commodity fulfilling a function of shelter and comfort. It is also an expression of culture, history, economics and social values. Past civilisations are, normally, first discovered through the archaeological remains of their buildings, roads, viaducts and so on. This gives a special status to building design and production compared to other human activities. If we are to embrace sustainable design and construction methods for our built environment, we need to steer clear of the traditional debate between form and function and adopt performance-based design and production methods. Performance, in this case, takes a wider meaning than mere comparison to some pre-set numerical indicators. It ought to embrace the three corner stones of the design triangle: firmness, commodity and delight. Such a design process ought to consider two important issues: the iterative nature of design and the interface between the various decision-making stages.

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D e s i g n p ro c e s s : o p e n v e r s u s c l o s e d In environmental terms, an open design process is concerned with designing buildings that use resources (energy, fresh air, fresh water, materials, etc.)to enable the building and its occupants to fulfil their roles and produce waste that is dumped in the ground. The design of a closed system takes a different view. The building is considered as a new living healthy entity where resources are used and

Unused resources Precipitation

‘Open’ design process

Wind Air emissions and noise

Waste air

Fresh air Energy Electricity, gas, fresh water

Waste heat Consumption

Material goods Plants

Waste water Material waste

Soil Unused resources

Air cycle ‘Closed’ design process

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Material cycle

Utilization

Water cycle 19.6

Energy cycle


re-used (whenever possible). This enables two objectives to be achieved: (a)reduction in the depletion rate of the natural resources, and (b)reduction in the amount of waste dumped in the ground and the various problems it generates. The diagrams in Figure 19.6 illustrate the main stages of such a design approach.

Design loop As has been discussed in Part 3, building design is concerned with devising solutions to problems of aesthetics, function and durability. An integrated design approach is likely to achieve better and sustainable solutions. Such an approach would consider the various constraints imposed by the brief, site and client. The designer would start by establishing the requirements for the design. The designer does so from analysis of the brief and by reference to design standards and guidelines. Once the requirements are set, the designer can identify the specific problems that the design brief presents and set some targets to be achieved. These targets would cover all aspects of performance: aesthetics, comfort, buildability, environmental impact and so on. The targets, once set, would form the benchmarks against which the design solutions are to be tested. The final design solution does not come all at once at the stroke of a pencil. The design process is a developmental and iterative process in which various design conflicts may need to be resolved. Once the design scheme is fully developed and all the technical details required to build it have been produced, rigorous checks on workmanship and components need to be kept if the quality of the final product is to match that of the design and specifications. Post-occupancy surveys of both the occupant’s perception of the quality of the environment and the performance of the building against both the set targets and the design standards need to be recorded and fed back into the design loop in the form of case studies. These case studies, whether it be of good practice or what to avoid, need to be disseminated so that future design exercises would make use of them.

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Chapter 20

Design strategies This chapter will seek to demonstrate how the physical principles described in the previous chapter can be applied to the design process by means of a number of strategies. The relationship between the various aspects of the building’s performance is discussed. The emphasis is placed on low energy design strategies. Throughout the chapter, it is the intention to help the reader develop an appreciation for a holistic approach to design and an awareness of some of the environmental and technological issues that can be integrated into the design activity.

I n t ro d u c t i o n For a building to be successful, at least environmentally, it needs to provide the correct conditions of comfort and functionality, without the penalty of excessive energy use. The following sections will discuss a number of design strategies that can be used to try to achieve that objective.

L o w e n e r g y s t ra t e g i e s Given the declared intention of this book to promote design approaches that would lead to minimum or no use of energy, it is appropriate to discuss some of the strategies used to minimise energy use in buildings and maximise any natural forms of energy. Of particular interest to this chapter is solar energy.

Keeping the heat in The thermal performance of a building has a direct bearing on the energy consumption of that building, whether it be for heating or

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cooling. This section will develop further the basic principles discussed in the previous chapter and will illustrate their practical implications. In cold climatic regions, the emphasis for the design is to keep the heat inside the building by increasing the ability of the building fabric to insulate against heat loss.

Th e r m a l t r a n s m i t t a n c e ( U - va l u e ) The previous chapter introduced, among other properties, thermal conductivity. This property is useful when comparing the thermal performance of different materials in order to select the appropriate ones. When looking at building components, however, or forms of construction (wall, roof, floor, etc.)individual materials’ conductivities will not be enough to give an indication as to the performance of the whole component made up of several materials. In such cases, the thermal transmittance, or U-value as it is commonly known, is used instead. It is the measure of the overall rate of heat transfer through a particular section of the construction. U-value is measured as the rate of heat flow in watts through 1 m2 of a structure when the temperature difference across the two faces of the structure is 1oC. In practice, the U-value is calculated using the thermal and physical properties of the materials that make up the structure. An example of a simplified U-value calculation is shown below. When very detailed analysis of heat flow across a component is required, a modified calculation method is used. This takes into account the effect of bridging materials in the component. For details of this method, reference is to be made to the Building Regulations, Approved Document L1: 2003. The external wall shown in Figure 20.1 has the following construction: outer leaf of brickwork; air cavity; insulation; inner leaf of concrete block and plasterboard. The properties of the various materials are as shown in Table 20.1. We would like to know the rate of heat transfer through this wall (the U-value). How do we go about it?The following steps would need to be followed:

•

• •

20.1

Notice the cavity is specified with a resistance, not conductivity. This is common in heat transfer calculations. You do not calculate the resistance for layers of air such as a cavity. Standard design values are normally used, according to the conditions. All the thicknesses need to be converted into metres (m). In this case they are divided by 1,000 to convert from mm to m. The layers of air on the inside and outside of the wall need to be included in the calculation. These are also specified with resistance values. We usually use standard values unless otherwise indicated. For the inside surface, RSi, we use a resistance value of 0.12 m2K/W. For the outside surface, RSo, we use a resistance value of 0.06 m2K/W.

D E S I G N S T R AT E G I E S

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Table 20.1: Properties of the materials used in the calculation example Material

l: thickness (mm)

k: thermal conductivity (W/mK)

12 120 100 50 102

0.18 0.58 0.038 Resistance =0.18 m 2K/W 0.84

Plasterboard Block Insulation Cavity Brick

•

•

We reconstruct Table 20.1 by adding a column for the resistance values and two rows for inside and outside air. For each of the solid materials, we divide thickness by conductivity to work out the resistance. It would look as shown in Table 20.2. The total resistance will now be converted into a U-value as follows:

U - value =

1 1 = = 0.29 W / m2 K Total resistance 3.391

This calculation method assumes that the wall construction does not include any bridging materials at all, which is not the case. For detailed and more accurate assessment of the U-value, the same calculation procedure is carried out through the thermally bridged elements of the wall to determine their thermal resistance. A further calculation is carried out based upon the proportion of the bridged elements so that the overall U-value of the wall can be determined. The answer is useful in a number of ways:

Table 20.2: Calculation of the thermal resistance values Material Inside air RSi Plasterboard Block Insulation Cavity Brick Outside air RSo Total resistance

l: thickness (m)

k: conductivity (W/mK)

0.012 0.120 0.100 0.050 0.102

0.18 0.58 0.038 0.84

R: resistance (m2K/W) 0.12 0.067 0.207 2.636 0.18 0.121 0.06 3.391

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• •

• •

We now know the rate of transfer through this wall. This information would be useful in determining the amount of heating required in a space enclosed by this wall. If we were to design a building with such an external wall construction, we need to ensure that it meets some statutory requirements related to the conservation of heat. In this case, the calculated value would have satisfied the e‘ lemental approach’ of the Building Regulations, Part L1: 2002. Coverage of the Building Regulations will be given in Volume 2, Environment, Technology and Sustainability. We could compare the thermal performance of various wall constructions even before they are built. This is a useful design evaluation tool. The calculation method can be adapted to work out the desired thickness of insulation in any form of construction. Usually the type of wall, floor or roof is decided upon for other considerations and the required insulation thickness is calculated from knowledge of the desired U-value.

Insulating materials A thermal insulator is a material that resists the flow of heat. This phenomenon is due to the wide spacing between the atoms of the material which includes voids filled by air, and this is a good insulator provided its movement is restricted. Insulating materials are characterised by a low density and low thermal conductivity. They are produced from three main sources:

• • •

vegetation (i.e. organic fibres); minerals (often volcanic in origin);and coal or oil (cellular plastics).

Insulating materials come in a variety of types:

• • • • •

pre-formed integral components (aerated concrete blocks); batts and rigid boards (expanded polystyrene boards); quilts; loose fill materials (fibres and granules);and materials formed on site (foamed polyurethane PU).

Insulating materials need to fulfil a number of performance requirements:

• • • • • • •

suitability for the purpose; strength and rigidity when required; moisture resistance; fire resistance; resistance to fungi and pests; compatibility with adjacent materials;and harmlessness to humans and the environment.

Table 20.3: A selection of inorganic insulating materials Material

General characteristics

Thermal conductivity

Application

Wood Wool slabs

Fire and rot resistant with good load-bearing capacity

0.077

Decking materials

Mineral Wool

Non-combustible, available in a variety of forms, loose, mats, batts, rigid slabs. Water-repellent, rot proof, contains no CFCs or HCFCs

0.031– 0.04

Cavity fill, fire stops, wall, floor and roof insulation

Glass Wool

Non-combustible water-repellent, rot proof, contains no CFCs or HCFCs. Loose, rolls, batts, slabs and laminate

0.031– 0.040

Cavity fill, compression resistant slabs, dry lining laminate

Table 20.4: A selection of organic insulating materials Material

General characteristics

Thermal conductivity

Application

Cork

Expanded granules formed into boards can be laminated to foams

0.042

Roof insulation (mainly flat roofs)

Fibre Insulation Board

Prone to moisture degradation. Bitumen impregnated boards have better moisture resistance

0.05

Wall lining, exposed s( ound absorption), floor insulation

Expanded Polystyrene

Combustible, water resistant, disolves in organic solvent, rot and vermin proof, no CHCs or HCFCs

0.033– 0.040

Walls, roofs, floors. Separate or as laminate

Extruded Polystyrene

Denser and stronger in compression with a lower conductivity. Low water absorption

0.025– 0.027

Cavity, pitch roof, floor insulation

Urea-Formaldehyde Foam

Used extensively in the 1980s. Emits irritating fumes

0.038

Cavity fill

Tables 20.3 and 20.4 give a summary of some of the characteristics of a selection of insulating materials.

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The use of many conventional insulating materials can lead to environmental problems. Some of these materials are manufactured using energy intensive processes and, therefore, total energy content, including that of the manufacturing process, needs to be considered. Natural materials on the other hand can achieve similar performance requirements (thermal/mechanical etc.)to those of conventional materials, with the added benefit of less environmental impact. Such materials include sheep’s wool, straw, hemp and recycled paper based products.

Insulated constructions If a building is not insulated it would be losing heat through its fabric (walls, floor, roof etc.). The way each of these elements is insulated depends on the methods of construction used, the availability of insulating materials, and on whether or not the insulation is added on to the building at a later stage in its life. Some of the methods of applying insulation to a building are described below. In external walls, insulation can be installed in one of three positions: internally, externally and in the cavity. The data in Table 20.5 illustrate these applications. The method of insulation used would not affect the rate of heat loss from the building, but it may affect its overall thermal performance depending on its position relative to the thermal mass (or even the lack of it). For instance, the building could be a lightweight one with internal insulation. In this case, the building interior would have a fast thermal response as it warms up and cools down quickly. If the building is of a heavyweight fabric and insulated externally, it would have a slow thermal response. This means it warms up and cools down slowly. It also means that it produces a more even thermal profile, with less temperature fluctuations. The relative merits of these options would depend on other considerations, such as the occupancy pattern of the building, the type of environmental services and controls used, and the energy saving requirements. Further discussion of these issues will be given in the next section. Traditionally, floors like other parts of the building were not insulated. The continuous improvements to thermal performance standards meant that new buildings and some existing ones, when refurbished, have their ground floors insulated to reduce the rate of heat loss. The various methods of installing insulation in floors are described in Table 20.6. The types of floors described here are those typical of UK domestic construction. The principles outlined could, however, be applied to other forms of constructions. In roofs, as in other parts of the building, insulation can be found at different locations according to the type of roof, type of insulation, method of construction, as well as other technical and economic


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Table 20.5: Methods for insulating an external wall Position of insulation

Typical applications

General issues

Cavity insulation

Can be found in full and partial cavity fill

A cheap form of insulation

Full fill is to be found in either new built w ( ith render/cladding) or in refurbished buildings Partial fill is very common in traditional cavity masonry walls

External insulation

Adding insulation and render to an existing building

Whether to use full or partial fill depends on the exposure level of site to rain An after construction fill takes the form of blowing or injecting the insulating material

Can be expensive if added on Provides weather protection

Used with cladding systems added to existing masonry as part of a refurbishment programme Used with lightweight cladding systems in new built

Internal insulation

Used on inside of inner leaf, either between battens/channels or as an integral part of the plasterboard If it's an add-on, consider the changes to internal details w ( indow reveals etc...)

factors. The diagrams in Table 20.7 show different methods of insulating a roof. The table is by no means comprehensive, but it gives an indication of the various technologies and techniques that can be found in practice.

Reduces thermal extremes in the fabric Reduces the risk of frost damage and cold bridging

Cheaper than external insulation The risk of fire needs to be considered The risk of condensation needs to be taken into account

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Table 20.6: Methods for insulating a floor Type of floor

Position of insulation

General issues

Timber floor

1. Laid between joists, fitting tightly and supported by netting

For position 1 Can be either board or quilt

2. Rigid boards laid over joists

For both positions Cold bridging needs to be considered If a vapour control layer is used it needs to be water permeable

Solid floor construction

1. Insulation below slab 2. Insulation above slab

Needs to be rigid board that resists loading Needs damp protection Cold floor under feet Will yield a warm floor under feet For both cases, cold bridging needs consideration

As Table 20.7 shows, there are various methods of using insulating materials in roofs. The choice of any particular method is dependent on factors such as the type of roof, its pitch, the roof covering and so on. However, in all cases, a major consideration is that of condensation. Whichever method of insulation is used, the risk of condensation ought to be eliminated. Usually the provision of ventilation on the cold side of insulation would help achieve that.

Solar energy and design There is often a reference to ‘passive’ design strategies, when the natural resources of energy and materials are harnessed to create buildings with little impact on the environment. There is nothing passive in a conscious decision to reduce energy use or waste. The term, however, came to be associated with any process that relies on using methods to tame the environment without recourse to energy intensive mechanical and electrical services. In this section, we will look at some aspects of a design strategy whose ultimate objective is to use less energy. To do this, the design must consider the relationship between


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Table 20.7: A selection of roof insulation applications Type of floor

Position of insulation

General issues

Pitched roof

1. Quilt laid between and over joists, supported by ceiling

Either fascia or soffit ventilation inlet is required

2. Quilt/board between rafters

Care is needed to provide a clear air path from eave to roof space Provide a ventilation gap on the cold side of insulation In high moisture rooms use a vapour control layer on warm side of insulation

Flat roof

3. Insulation below deck: Cold roof n ( ot ideal in UK) To be used with timber roof construction only

Insulation laid over vapour control layer supported by ceiling Needs ventilation gap above Various types can be used

4. Insulation above deck: Warm roof s( andwich/ inverted)

Insulation is laid above deck, either below waterproof membrane s( andwich)or above it (inverted)

Can be used with timber, concrete or metal structural decks

If of the second type, no need for vapour control layer but must resist water

solar energy and the building. One can also find references to both passive heating and passive cooling. The site, climate and type of building would dictate which of the two can be adopted as a strategy. Here we will discuss some of the basic principles relating to design strategies that endeavour to engage with environmental issues as part of the design process.

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Site A design that is to be in tune with nature would need to take into account the characteristics of the site. Such characteristics include physical ones, such as microclimate, topography as well as socio-economic and cultural ones. In this section, only the physical characteristics are covered. The discussion will cover the impact that those characteristics are likely to have on any passive heating/cooling strategy. The availability of solar radiation depends on factors such as the geographical location, season, time of day and orientation. Though the discussion here is primarily for European climates, the principles can be applied to any of the world’s climatic regions. In Europe, except for the southern summers, usually there is no need for cooling in domestic buildings. Non-domestic buildings, however, would need some degree of cooling even in Northern Europe due to large internal gains from equipments and people. The need for heating is a requirement throughout the various climatic regions of the continent during winter. According to Cofaigh et al. (1996), ‘in many places in Europe, except during night-time in the depth of winter, a dwelling can be naturally heated, free of charge ... without environmental degradation’. The guiding principles for any design strategy committed to reducing energy use by exploiting the site are that:

• • •

the building should be located on site in a way that it benefits from the best available microclimate; in cold climates, when the design strategy is primarily for heating, both insolation (availability of solar radiation)and shelter from wind need to be considered;and in hot climates, when the requirement is mainly for cooling, the use of prevailing winds to aid natural cooling would need to be explored.

Suburban and rural sites usually offer more choice in terms of site planning options when compared to urban ones. When considering the

20.2


availability of solar radiation, solar collectors (windows, sunspaces, etc.)should be orientated as shown in Figure 20.2. Care should also be taken to avoid causing overshadowing by vegetation or taller buildings. There is a need to consider shelter from prevailing winds during the heating season, as these would increase heat loss. During the summer season in southern Europe, westerly orientation is difficult to provide shading for, given the lower altitude angle of the evening sun. This can be a problem particularly because such an orientation would have high air temperature at this time of day. The prevailing winds could be exploited during the hot season to generate some natural cooling. For detailed discussion of how the site can be best used, the reader is referred to Volume 2, Environment, Technology and Sustainability.

Building The building form and layout result from a process which involves a complex set of functional, technical and aesthetic considerations, as discussed previously in Part 3. The need to minimise energy consumption alone should never determine the design solution. On the other hand such an objective, if adopted at an early design stage alongside other design priorities, would lead to elegant, comfortable and environmentally friendly buildings. In general terms, energy considerations can be incorporated into design strategies that make use of the building form to maximise solar gains and minimise heat losses. The use of a compact form would produce the least heat loss for a given volume (see Figure 20.3). The compact shape rule, however, must be used with diligence, as its application to large-scale buildings would require more energy input for lighting and ventilation of such deep floor plans. To illustrate this

20.3

225

226


20.4

point, the following comparison is considered. Two office interiors of a similar floor area and volume have their floor plans square (48 m each side)and shallow L-shaped (69.2 m each leg)respectively. For the similar environmental conditions inside (lighting, heating etc.), the squareshaped office used around 10% extra energy. Thermal zoning of floor plan layouts can be used to shield heated spaces from the outside. Buffer zones of rooms with no or little heating can be located towards the cold side of the building. To make good use of sunspaces, they ought to be separated from adjacent heated rooms by tightly fitting doors. This would allow greater control over heat transfer by infiltration, particularly when heat exchange between the sunspace and adjacent rooms is not desirable as is the case of night-time heat loss or daytime summer heat gain (Figure 20.4). Another example of using buffer zones is the inclusion of draught lobbies that reduce heat loss by infiltration due to continuous door openings and shutting.

Thermal mass When the energy from solar radiation is to be used for passive heating, there is a need to store the energy collected in the walls and floor, provided these have a high thermal mass. The storage medium would release the heat by emitting radiation. The darker the surface of the storage medium, the better it performs. The other benefit of thermal mass is to slow down the building’s response to changes in external temperatures, such as during warm/hot summer days. Examples of using thermal mass in buildings can be found in all climatic regions


of the world and throughout the centuries. The large variety of styles and types can extend from traditional mud huts in the Arabian desert and lightly coloured rendered buildings of the Mediterranean climate to the Australian House of the Future in the Swan Valley to the rammed earth houses at Isle d’Abeau in France.

Glazing Windows are fundamental to building design. They allow daylight in, provide views to the outside, collect solar energy, lose heat to cold outside air, they cause overheating when not shaded and allow fresh air in. They are the bridge that connects the internal environment to the external one. With regard to a design strategy whose objective is to reduce energy use, they play a major role in achieving that objective. Windows should be designed to maximise solar gains and minimise heat losses in winter without causing any overheating in summer. The orientation of windows should take into account the geographical location, the solar angles throughout the seasons and the climatic conditions. Suitably oriented windows are often the first manifestation of climate responsive architecture. In the northern hemisphere, south-facing windows provide maximum winter solar gain. The optimum orientation to capture the sun would depend on the latitude of the location and that, for most locations in Europe, is shown in Figure 20.2. Vertical or near-vertical glazing gives better performance for low winter solar angles. To overcome the penalty of heat loss through glass, in the absence of solar radiation, shutters can be used. Both internal and

20.5

227

228


external shutters have traditionally been used. If insulated, shutters can be effective in reducing heat loss. However, when these are used internally, they can lead to some condensation on the internal surface of the glass. Under certain conditions of geographical location, size of glazing and orientation, prevention of overheating may be required. West-facing windows are particularly susceptible to overheating given the low angle summer sun. Low-pitched glazing is to be avoided to help reduce summer overheating. Roof lights, if used, need to be directed away from high angle solar sun from the south (see Figure 20.5).

Ve n t i l a t i o n The need for natural ventilation has already been demonstrated on page 207 in the previous chapter. In this section, the discussion will centre on the use of natural ventilation as part of an environmental design strategy with a view to reduce energy use in the building. The various elements that could inform such a strategy are explained. The provision of natural ventilation is dependent on the site. Space planning would, both horizontally and vertically, determine the effectiveness of ventilation. Window design is important to both the ventilation strategy itself, as well as the overall effectiveness of the design with regard to energy use as well as other technical, functional and aesthetic considerations.

Site Wind is one of two forces behind natural ventilation, with the other being buoyancy caused by temperature differences. The site exposure would inform the decision on positioning of ventilation inlets and outlets, as well as the provision of shelter to reduce unnecessary heat losses. The effectiveness of wind-driven ventilation depends partly on the wind speed. This is, in turn, dictated by the height above ground and the type of terrain. Wind speed increases with height above ground. The presence of obstacles in the path of wind would modify its speed. Trees and other buildings and screens would reduce the wind speed. Rural, country wind speeds are higher than those in urban areas. This makes it more difficult, in these sites, to achieve effective ventilation under natural conditions. Wind pressures are positive on the windward side of any given building. Any openings in the windward façade would allow outside fresh air into the building. The roles are reversed on the leeward side as the pressures are negative. Any openings on this façade would let stale air out of the building. This is often used to locate ventilation openings in buildings, as seen in Figure 20.6. The use of natural forces to drive the


229

20.6

wind around the building would mean a reduction in energy use to service the building. When natural ventilation is used as part of a passive cooling strategy, correct positioning of ventilation openings become even more important. This is because both indoor air-quality and thermal comfort are heavily dependent on it. The diagram in Figure 20.7 illustrates how the direction of prevailing winds was made use of. 20.7

Space planning Introducing the air into a room by means of windows can be achieved either by one-sided or double-sided ventilation, depending on the depth of buildings and ease of access to outside air. Wind-driven cross-ventilation with windows on both sides is effective in rooms with open-plan layouts or low partitions (see Figure 20.7). Under these circumstances rooms with a depth up to five times the height can be ventilated effectively (for cooling). When a room can be ventilated from one side only, the depth to which it can be ventilated effectively is less than that for double-sided ventilation. Rooms up to two-and-a-half times deep as they are high can be ventilated effectively. In the case of wind-driven ventilation, the turbulence created by the wind can drive the air in and out of the room. When ventilation is caused by buoyancy, the way the window opens becomes even more important. This is discussed further in the fenestration section below.

Wind-driven double-sided (cross) ventilation is most effective for summer cooling rooms up to five times as deep as they are high. Further details can be sought from BRE Digest 399, Natural ventilation for non-domestic buildings, 1994.

230


20.8

Fenestration Most natural ventilation systems for buildings use windows to control the volume and direction of air flow. Windows are designed to offer certain levels of control over the degree of openness, area of opening and the way it opens. A casement window offers a full opening facility and its swinging sash can divert passing air into the room. A double hung sash window can open only to half its total area, but can be effective, particularly if the opening is divided between top and bottom, as this makes use of the stack effect. An awning window admits air and gives protection against light rain. Furthermore, it does not have the disadvantage of clashing with blinds that the single swivel window has (see Figure 20.8). For good stack effect, tall windows are better than horizontal ones of the same size.

Mechanical ventilation with heat recovery Sometimes in urban environments a natural ventilation system is not feasible due to air quality, noise issue or both. Under such circumstances, a mechanical ventilation system could be used in combination with a heat recovery system (see Figure 20.9). The system operates on the principle of taking the heat from exhausted stale air and pumping it back into the cool fresh air supplied from outside. By using this system, the need to supply the ventilated room with heat to warm up the cool fresh air is reduced. Such a system can be effective if the room or zone it ventilates is well sealed and when the air volume flow rate is around 500 m3/hour, according to Nicholls (2002). For a room with a floor area of 18 m2 and a height of 3 m, this would represent around nine air changes per hour. This ventilation rate would put such a room in the domestic kitchen and bathroom category.

20.9


Daylight Lighting accounts for a considerable amount of energy use in buildings. Although energy used for lighting in domestic buildings represents only 4% of the total energy used, it can get as high as 20% in naturally ventilated offices. Given that electricity, which has a conversion efficiency of around 31.5 to 37% (Nicholls, 2002: 5), the reduction of any lighting loads becomes even more important. Any attempts to design buildings that consume less energy for lighting is to be welcomed. Furthermore, the provision of daylight should be linked to a holistic environmental strategy whose objective is to reduce overall energy use. An effective daylight strategy requires:

• • • •

fenestration, internal space layout and finishes to be designed for optimum daylight entry and distribution with minimum or no glare; reduction of heat loss through glass is to be considered; minimising excessive solar gains that can cause overheating;and the electric lighting system and its control to be designed for integration with the daylight system.

Fenestration For a detailed analysis of the physical and technical issues relating to the daylight factor the reader is referred to Volume 2 in this series, Environment, Technology and Sustainability. In this section, the emphasis of the coverage is on window design with regard to daylight provision. Although the sun is the source of light during the daytime hours, in lighting design daylight refers to light that, though originated from the sun, reaches the surface of earth after reflecting from the sky’s vault. In other words, direct sunlight that casts shadows is not included in daylight analysis. The amount of natural light at a given point inside a room is determined by a number of factors. The most important of these is the proportion of sky which can be seen directly by that point through any windows and roof lights (Figure 20.10).The sky at the zenith (overhead) is three times brighter than at the horizon. For this reason the higher the window head, the more light penetrates the room. Some of the light that reaches any given point in the room is by reflection from external and/or internal surfaces (Figure 20.11). The internal surface finishes and room shape contribute to the visual environment and its perception. Tall, shallow rooms with lightcoloured surfaces seem brighter compared to low, long rooms with windows at the narrow end, and rooms with dark coloured surfaces always prove difficult to illuminate with daylight. Windows should be located away from interior focal points of rooms, as this can cause glare on the visual task.

20.10

231

232


20.11

Daylight and heating Introducing daylight into a building can lead to an increase in energy use if it is not properly considered alongside other aspects of environmental design, as windows are liable to heat losses and gains. The most effective method of reducing heat loss through glazing is to keep its area to an optimum that would provide sufficient daylight without the penalty of heat loss. For experienced professionals, intuition and experience would allow such a judgement to be made. The LT method

20.12


for design can help young, inexperienced designers carry out some preliminary analysis to help decide on the best course of action when dealing with non-domestic buildings (see Figure 20.12). It is a manual design tool used for calculating energy performance in non-domestic buildings. As a rule of thumb, in commercial interiors, a glazing ratio of more than 40% (for double glazing)is likely to increase the overall energy used for most orientations. This is because the increase in both heating and cooling requirements is likely to outweigh any energy saving in electric lighting.

Daylight and cooling The use of windows to provide daylight can lead to excessive heat gains in summer, particularly in non-domestic buildings. In his quest to prevent overheating while still allowing daylight in, the designer needs to separate the heat component of the sun’s rays from the daylight component. To achieve this a number of features are available at his disposal. Louvered blinds (Figure 20.13)can be effective if used externally as compared to being installed on the inside. When they are installed between panes of double or triple glazing, they would offer a shading performance similar to that when installed externally, but at a lower cost. Brises soleil (Figure 20.14), which consist of an array of vertical plates fixed horizontally above a window, can often combine shading with a secondary function as a maintenance gantry, a walkway or a balcony. The use of tinted and reflective glass is to be discouraged. For these materials, the shading effect leads to a loss in lighting transmission. Detail discussion of the design of shading devices will be covered in Volume 2 in this series, Environment, Technology and Sustainability.

20.13

20.14

233

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Sound insulation Dealing with sound insulation issues does not require any energy input as such. However, since the design of sound-resisting structures would involve the choice of certain materials that would form part of the building fabric, this makes the link between the provision of sound insulation and the thermal performance of the building very strong. Since promoting a holistic approach to design is at the heart of this book, dealing with sound-related issues as part of a design strategy that has sustainability at its heart is more than desirable. Given that sustainable living requires us to develop more and more brownfield sites, in urban areas, where noise levels are likely to be high, one can see the need for such a holistic approach.

Noise in modern societies Noise, and its effects on humans, is on the increase in modern societies, particularly in industrialised countries. Its main effects on people can range from interference with speech and sleep to annoyance, and, if sufficiently intense, it can lead to adverse physical and psychological effects such as hearing loss, stress and depression. According to research work published in 1996, and cited by Crocker (1997), around 5.5 million US workers in manufacturing and utilities are exposed to noise conditions that are hazardous to hearing.The same reference cites another survey in Germany whose results indicate that 70% of the citizens are annoyed by road traffic noise. In the UK, the 1999/2000 national survey of attitudes to environmental noise has showed a marked increase, compared to 1991, in the number of people adversely affected by noise from a variety of sources. Noise from neighbours was the biggest culprit, as the percentage of people affected was 26% , followed by road traffic, which adversely affected 13%of respondents. According to the European Commission (2000) at least 25%of the EU population experience a reduced quality of life due to noise. The situation is not likely to get better in terms of environmental noise levels. This is because population centres, with all their noise producing activities, are expanding all the time. Furthermore, with the increase in road and air traffic, the noise levels to which people would be exposed to outdoors are likely to be higher. The situation would require even more stringent standards of sound insulation and noise control to create adequate living, working and leisure spaces both outdoors and indoors. Since the main concern of architects, technologists, surveyors and the like is the building, as opposed to the urban context, the discussion in the following section will be restricted to noise in buildings and their immediate surroundings.

Provision of good acoustics A good acoustic environment is characterised by both the presence of sound and the lack of it. We enjoy listening to music, people in


conversation or the sound of birds on a summer morning. But we also, under other circumstances, enjoy peace and quiet. We wish not to listen to continuous loud traffic noise or to music which is appealing to nextdoor neighbours but not ourselves. The provision of good acoustic conditions falls in one of two categories, namely room acoustics and sound insulation. The first type of intervention is mainly concerned with the creation of good hearing conditions inside a given room or space where the emphasis is on appreciating the sound, such as lecture rooms, performance theatres and so on. For this type of acoustical design, the room shape, size and proportions, as well as the surface finishes, affect the quality of sound. The geometry of the room is important as it determines the paths along which the sound will travel. Standing waves in small rooms with parallel walls create a particular problem. This phenomenon manifests itself by certain frequencies of the sound being exaggerated by multiple reflections. Slightly tilting or skewing the walls would eliminate this. It is also useful if the dimensions of the space do not fall into any simple geometrical proportion, such as 1:2 or 2:3. The presence of concave surfaces would help focus the sound and reinforce it at the foci. Convex surfaces scatter reflected sound, helping to reinforce sound levels in all parts of the room. The room size can also affect the extent of echoing, or reverberation time, to use the correct technical jargon. This is the time in which a sound will bounce about a room before decaying to an inaudible level. Reverberation time increases with increasing room volume because of the longer distances travelled by the sound wave between successive reflections. The effect of introducing sound-absorbing material into the room will be discussed in the next section. To achieve the appropriate reverberation time for a given hall is important. For speech, such as the case of a class room, a short reverberation time is best, so that short consonant sounds are heard clearly. If the reverberation time is too short, the speaker would get little feedback of their voice and would have no sense of how well or bad his/her voice is carrying to the audience. Music requires longer reverberation times. This would help blend the sounds of instruments and/or voices in a way that makes the musical experience enjoyable. When the hall has a short reverberation time, the music would sound dead and brittle. On the other hand, if the reverberation time is too long, the music would lack clarity and definition as the direct sound is mixed with its echo. Table 20.8 gives typical reverberation times for auditoria of different sizes. When there is a need to provide quiet conditions, such as for sleep or study, the design takes a slightly different approach. Both space planning and choice of materials are as important as each other. To use space planning to good effect, the building is arranged in such a way that the quieter rooms are shielded from the source of noise by rooms that do not require the same degree of quietness. For instance, a kitchen

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Table 20.8: Reverberation time for a selection of spaces (adapted from Crocker) Internal space Dwelling Dining, assembly, multi-spaces Industrial processes Recording rooms Drama, high speech clarity Conference, lecture, classroom Multipurpose audience, musicals Opera, chamber orchestra, ballet Orchestra, organ, chorus

Reverberation time (s) 0.8– 1.0 0.8– 1.0 0.8– 1.0 0.4– 0.6 0.4– 0.8 0.6– 0.8 1.2– 1.6 1.4– 1.7 1.7– 2.2

is located towards the noisy busy street and protects a bedroom located behind it. When deciding on where to locate the building on site, the distance from a given noise source can be used to reduce the noise level. The use of soft landscaping in the intervening ground can help reduce the intensity of sound. The bulk of the shielding effect from external noise would need to be provided by the building fabric through the careful choice of materials (see the section below). The same principle can be applied to noise generated internally within the building.

Choice of materials The materials used in a building would determine the way that building would perform with regard to both the provision of good conditions for hearing as well as providing peace and quiet. Materials used as finishes would affect the reverberation time of a given room. For a given room volume, their ability to absorb sound would determine the length of reverberation time. The presence of materials with high absorption capability, such as soft furnishing and acoustic ceiling tiles, will increase the overall absorption provided inside the room. This, in turn, would lead to a reduction in reverberation time. Hard materials tend to reflect sound and absorb little of it while soft ones tend to absorb more sound. Table 20.9 gives absorption coefficient values for a selection of materials. The effective absorption of a given surface depends on both the absorption coefficient of the surface material and the area of that surface. It can be worked out by multiplying these two factors together. The resulting absorption is measured in m2 sabins or ‘absorption units’. The total absorption of a room is given by the sum of the effective absorptions provided by each of the surfaces in the room.


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Table 20.9: Absorption coefficients for a selection of materials and finishes (after Crocker) Material

Frequency (Hz) 63

125

250

500

1000

2000

4000

0.18 0.25 0.01 0.15 0.02 0.15 0.08 0.02 0.014

0.24 0.83 0.01 0.12 0.06 0.45 0.15 0.02 0. 10

0.68 1.00 0.01 0.10 0.14 0.90 0.30 0.03 0.06

0.85 1.00 0.02 0.07 0.37 0.92 0.50 0.03 0.04

1.00 1.00 0.02 0.06 0.60 0.95 0.60 0.04 0.04

1.00 1.00 0.02 0.07 0.65 0.95 0.70 0.05 0.03

0.18 0.35

0.06 0.25

0.04 0.018

0.03 0.12

0.02 0.07

0.02 0.04

0.52 0.44 0.60

0.68 0.60 0.74

0.85 0.77 0.88

0.97 0.89 0.96

0.93 0.82 0.93

0.85 0.70 0.85

3

Fibreglass / Rockwood blanket 6 ( 0kg/m ) 25 mm thick 50 mm thick Concrete floor Wood joist floor, varnished Carpet, heavy on concrete Plush curtain deeply folded Acoustic plaster, 10 mm sprayed Hard masonry b ( rick, plaster..) Plaster on lath Glass heavy plate ordinary window Seats f(igures per seat) upholstered, occupied upholstered, unoccupied wooden chairs, occupied

0.34 0.28

The various devices used for sound absorption can be classified into one of three main types of absorber. Porous absorbers are used for high frequency absorption. These consist of cellular and fibrous materials, such as fibreglass, mineral wool and open cell foams. Typical applications include: acoustic tiles, acoustic blankets and acoustic plaster. These are most effective at frequencies above 1 kHz. To improve their low frequency absorption, slightly, their thickness can be increased. Panel absorbers consist of fixed panels of materials with a space behind, which can be filled with air or may contain a porous absorber. The material could be a sheeting material such as plywood or an integral part of the fabric, such as a window or a suspended ceiling system. These absorbers are most effective at low frequencies between 40 and 400 Hz. The maximum absorption is dependent on both the mass per unit area of the panel and the depth of the air space. The third type of absorbers is Heimholtz resonators. These are air enclosures with a small open neck. The air in the opening will vibrate and energy is absorbed from the sound waves. The cavity may contain materials other than air and be part of a continuous structure, as is the case of perforated acoustic tiles. This type of absorber can be effective,

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but only over a very narrow band of frequencies to which the device can be tuned. This is particularly useful when controlling certain sounds inside rooms. Choosing materials for sound insulation is based on different performance criteria. The overall sound insulation of a structure depends on its performance with regard to the general principles governing sound insulation. These are heaviness, completeness, flexibility and isolation. Heavyweight structures transmit less sound energy than lightweight structures. This is because the high density of heavyweight materials would restrict the extent of sound vibration inside the material. The mass law stipulates that the sound insulation of a single leaf partition is proportional to its mass per unit area. Composite constructions, such as plastered brickwork, are considered as single-leaf construction provided that the layers are bonded together. The doubling of mass would yield around 5 dB of sound insulation. The effectiveness of a structure against noise is affected by its completeness. The presence of small gaps in a wall, for instance, can greatly reduce its sound insulation capability. For example, the presence of a gap with 0.1% of the total area of a brick wall would reduce the sound insulation of the wall from 50 to 30 dB. Gaps in structures are often the result of poor detailing and workmanship of joints around partitions and openings (windows/doors). The level of sound insulation given by the mass law does not hold true over certain frequencies for highly stiff materials. The loss of insulation is caused either by resonance or coincidence effects. This is particularly a problem in the air space of a cavity construction. The use of an insulating blanket, such as fibreglass, in the cavity can help reduce the effect of resonance and coincidence. Discontinuous constructions can be used effectively to reduce sound transmission through a structure. This principle finds its application in the use of air cavities in windows, in floating floors and resilient mountings for vibrating machines. The use of double structures separated by resilient mountings is a concept used with much success in the design of broadcasting and concert buildings where a high level of sound insulation is required. The provision of good aural conditions for work, rest or sleep and internal acoustical conditions to enjoy performance and entertainment are important factors we must consider in the design of buildings. Furthermore, for some types of building, such as dwellings and schools, there are certain regulatory requirements that need to be met. In most circumstances, the ordinary materials used to build are sufficient to achieve the design targets. However, these materials must be used carefully and correctly.

Chapter 21

Case studies

Case studies of what can be described as successful designs by wellknown architects can be found in a variety of published media, such as books, journals and websites. These design precedents, though they are very useful and informative, their usefulness to students is limited sometimes. Published good design is by famous and well-known architects to whom the student at times does not relate. This is one of the reasons that a different approach is taken to the use of case studies. The design examples presented in this chapter were designed by students in Architecture and Architectural Technology of various years and abilities. It is hoped that they would help to portray ways of engaging with design issues from a student's perspective. Each of the projects had a different emphasis and level of complexity. All three, however, tried to address some of the technological and environmental issues that many architecture courses discuss.

A house on an urban site The work described in the following section is that of a first-year student. The brief was to design a house for an artist, providing working and living accommodation. The site is located in the centre of Sheffield, UK, on the corner of Holly Street and Holly Lane, opposite the city hall. The urban fabric is made up of mainly commercial and leisure premises. The site is situated in a vibrant area of the city centre that comes into life at night. The buildings surrounding the site vary from the city hall, an early twentieth-century stone-clad building to mixed-use threestorey brick developments. Given a corner plot, the site opens up towards the east, with the longer façade facing south across the way from the city hall.

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Apart from the provision of working and living space, the design solution was required to address the wishes of the client for an e ‘ nvironmentally conscious design’. The student’s design objective was to design a comfortable and pleasant living and working space within a building that interacts well with its environment. The design intentions were expressed as follows:

• • •

maximise the use of passive design strategies; design a building with flexibility of space usage in mind;and introduce plenty of daylight into the studio.

The interpretation of the brief is presented in this section under three headings: building form, its fabric and the use of low-energy features.

Building form The form of the building was developed from a desire to create two distinct spaces: a working space and a living one, and linking them by a series of terraces. These terraces would provide access to the outside and privacy in an urban setting. The desire to design a building that offers flexible use of space has lead to the choice of an orthogonal disciplined structural grid of beams and columns. The use of such a grid has led to an open plan into which cellular rooms can be inserted between non load-bearing partitions. The ground floor is occupied by the gallery space and the garage to the east, while the studio is situated to the west. The latter extends vertically over two floors, with its winged roof providing daylight at high level. The living space occupies three floors over the east side of the building and opens up towards the south and west. Using the gap between the two wings of the building, windows on all three upper floors of the accommodation block face west away from the busy piazza on the south side. Daylight and natural ventilation are introduced into the rooms without the penalty of excessive noise. This has lead to the creation of an airy and well-lit atmosphere inside the building.

21.1

CASE STUDIES

21.2

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Building fabric The building shell consists of a lightweight highly insulated frame on the inside and an external cladding of honed stone, shiplap timber board or brick masonry. The extensive use of stone cladding and masonry on the south elevation allows the building to blend into its immediate surrounding and provide a heat sink for summer solar gains. The role of this thermal sink is complemented by two other features, the cast concrete floors and the stack effect. Throughout the building the floors are precast hollow concrete planks which are delivered on site and hoisted into place. They are supported by a series of universal steel beams connected to a grid of steel beams. Large areas of the floor slabs are exposed to direct solar radiation. During the heating season, solar gains during the day will be released from the mass of the floor at night. In the summer season, the solar gains stored in the floor will be dissipated at night by means of the night-time ventilation. The use of double and triple height rooms helps to ventilate the inside of the building by means of the stack effect.

Low energy strategy The provision of a well day-lit environment in the studio is achieved by means of roof lights high above the working space on the ground floor. Given that three-quarters of the area of roof lights is facing away from solar gains, this will reduce the penalty of high gains in summer. The high thermal mass floors contribute to some passive gains in winter. The adoption of an east-west double aspect for the living accommodation means that natural ventilation can be introduced into the building without opening it out directly onto the busy piazza on the south side. The use of highly insulated fabric would help reduce the demand for energy use. A combined heat and power unit is specified. The unit can run on either gas or oil. The heating system to be used is an under floor one. The speed of construction afforded by the choice of the structure and fabric, and the elimination of wet trades, would result in less transport activities into a city centre site.

A re s e a rc h s t a t i o n i n A n t a rc t i c a This case study is one of the projects that second-year students have undertaken recently. The brief was based on an international competition, launched in 2004, to design a wildlife research station to replace an ageing one in South Georgia in the South Atlantic. The objective of the brief was to design a working/living enclosure in such an extreme environment. Given the logistical difficulties, the brief asked for design solutions that can be built quickly and easily with minimum impact on the local environment. The project was used as a vehicle to integrate

CASE STUDIES

21.3

various aspects of the taught course together into a common output. The following sections present the ideas and views of the student as submitted.

The site Grytvicken is the main port on the east coast of the island of South Georgia. It was decided to locate the research station in this harbour locality given its sheltered location and logistical convenience. A look at the local climate conditions revealed the direction of the prevailing winds to be from the west. Warm winds blow from the north-west while cold winds come from the Antarctic region with a south-westerly direction. This was taken into account when the orientation of the building was decided upon.

Building form and layout The building is divided into three pods, each one housing a group of activities and having an area of 78 m2. The pods are connected by a draught lobby which houses a storage area and allows access to all three areas. Thermal comfort level requirements meant that spaces with high levels of activity are located to the south and west, while the sleeping accommodation is facing the warm north-westerly breeze.The almost circular floor plans provide a compact shape that reduces heat losses. The shape of the roof encourages the ventilation of the space it encloses.

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21.4

Building fabric The building fabric follows a modular pattern and consists of prefabricated, highly insulated panels that arrive on site ready to be assembled. Having a modular construction reduces construction time even further, as panels are interchangeable. The panels are made from plywood and Douglas fir timber, with 350 mm Thermafleece insulation sandwiched in the middle. The roof of each pod is constructed from radial rafters supported by a series of perimeter columns and converging onto a central column. Roof panels, which are similar in construction to wall panels, slot between the rafters. The roof deck is covered by a PTFE membrane, which is raised off the face of the deck using galvanised steel pegs leaving a 30 mm ventilation gap. The columns are supported by steel helical screw foundations driven into the ground. Above ground, the columns are connected by a series

21.5

CASE STUDIES

of ring and radial beams that support the floor construction, which, in turn, supports the walls.

Resources Given the harsh weather conditions, the use of energy will exceed what is normally expected in a moderately (by comparison)cold climate, such as the UK. The design has incorporated some ideas that would reduce carbon emissions. The use of mechanical ventilation with heat recovery was specified. This would reduce the heating load. A super-insulated structure such as this one (wall U-value =0.1 W/m 2K) will keep the heating load under check. A wind turbine is specified. This would generate part of the electrical load required and reduces the running time of the main fuel-burning generator.

A re t a i l c e n t re i n s u b u r b i a As part of an undergraduate degree programme, final-year students undertake a major design project from inception through to construction drawings. Using a ‘live’ brief, the project runs over two semesters, with staged submission and feedback throughout. The design brief for the academic year 2004/05 was based on a competition to design a retail outlet on the outskirts of Cheltenham in Gloucestershire, UK. The building has a total area of around 15,000 m2, including some 2,300 m2 of external space (builder's yard, etc.). The following headings are some of the specific issues brought to the attention of the students for them to explore:

• • •

sustainability –how could it be promoted through long-life, loose fit, low energy strategies? environmental strategies – how could this building type be designed to consume less energy? given the efficiency of an orthogonal grid for retail purposes, does the retail building as a whole have to be rectangular?

The work is presented as submitted by the student.

Site and space planning The design uses the site to good effect, locating the building at the far end opposite the noisy site entrance, and by wrapping the building around the garden centre which becomes the focus of the development. The north south orientation allows the width of the building (around 48 m)to lend itself to passive control strategies. The retail activities are organised over two floors of open plan space. The upper level is a mezzanine floor suspended from the roof.

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21.6

21.7

Structure and fabric The structure consists of 18 primary arched glue laminated trusses. These 1.5 m deep radial arches span the entire depth of the building at 47.7 m span and rise to a clear headroom of 17 m at mid-span. At the south façade the arches are spaced at 5 m centres. Given the curvature of the building, their spacing at the north façade is around 9.5 m. In the transverse direction, the arches are connected by 18 secondary gluelaminated trusses spaced at 3 m centres. They provide bracing to the primary arches and help support the roof deck. The shell construction consists of two layers of plywood that support a series of Masonite beams at 600 mm centre between which 100 mm of insulation is installed. The outer deck is a single layer of plywood covered by a Sarnafil single-ply roof membrane. In some places, the membrane is replaced by a tongue and groove weatherboard. The floor slab is 200 mm thick concrete, insulated internally using 50 mm rigid insulation and 75 mm screed. The green house, where the garden centre is housed, consists of a glass dome supported by 10 semicircular glue-laminated arches intersecting at the top of the dome.

CASE STUDIES

21.8

Environmental strategy The building is designed to operate with minimum heating input and no mechanical space cooling. Glazing accounts for around a third of the external surface area facing north and about the same on the south elevation. This would allow plenty of daylight into the retail space. The south-facing glazing has solar protection in the form of movable louvres with integrated photovoltaic panels. The louvres can also be used to obscure the clear sky during winter nights and reduce heat loss by radiation. The ventilation strategy is of a mixed mode. In winter, mechanical ventilation with heat recovery is to be used. During the summer period, only the inlet is mechanical, while the exhaust is by means of high level openings in the roof ridge. Both air pressure and buoyancy would contribute to the process.

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Part 5

Bibliography Allen, E. (1980) How Buildings Work: The Natural Order of Architecture. Oxford: Oxford University Press. Anon. (1999) A Green Vitruvius – Principles and Practice of Sustainable Architectural Design. London: James & James. Baker, N. and Steemers, K. (2000) Energy and Environment in Architecture: A Technical Design Guide. London: E & FN Spon. Building Research Establishment (2000) The 1999/2000 National Survey of Attitudes to Environmental Noise: Volume 2 Trends in England and Wales. Report No. 205216f. Chartered Institution of Building Services Engineers (1999) CIBSE Guide A: Environmental Design. London: CIBSE. Cofaigh, E.O., Olley, J.A. and Lewis, J.O. (1996) The Climatic Dwelling: An Introduction to Climate-responsive Architecture. London: James & James. Crocker, M.J. (ed.) (1997) Encyclopedia of Acoustics, Volume 2, Part VIII: Noise: Its effects and control. New York: John Wiley & Sons. Edwards, B. (ed.) (1998) Green Buildings Pay. London: E & FN Spon. European Commission (2000) The Noise Policy of the European Union. Luxembourg: Office of the Official Publications of the European Union. Hawkes, D., McDonald, J. and Steemers, K. (2002) The Selective Environment: An Approach to Environmentally Responsive Architecture. London: Spon Press. Hyde, R. (2000) Climate Responsive Design: A Study of Buildings in Moderate and Hot Humid Climates. London: E & FN Spon. Jones, D.L. (1998) Architecture and the Environment: Bioclimatic Building Design. London: Lawrence King Publishing.

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Marshall, D. and Worthing, D. (1990; 3rd edn 2000) The Construction of Houses. London: Estate Gazette. Nicholls, R. (2002) Low Energy Design. Oldham: Interface Publishing. Rennie, D. and Parrand, F. (1998) Environmental Design Guide for Naturally Ventilated and Daylit Offices. London: Construction Research Communications. Steele, J. (1997) An Architecture for People: The Complete Works of Hassan Fathy. London: Thames & Hudson Ltd. Thomas, R. (ed.) (1996; 2nd edn 1999) Environmental Design: An Introduction for Architects and Engineers. London: E & FN Spon. Wines, J. (2000) Green Architecture. Cologne: Taschen.

Webliography http://constructionresources.com (19 August 2005) http://secondnatureuk.com (19 August 2005) http://home.wlv.ac.uk/~in6840/Daylightfactor.htm (18 August 2005)

Part 6 Structural considerations INTRODUCTION, 253 Chapter 22 STRUCTURAL MATERIALS, 255 Introduction, 255 Structural materials, 255 Clay bricks, 255 Concrete blocks, 258 Concrete, 261 Timber, 262 Structural principles, 264 Chapter 23 STRUCTURES FOR DOMESTIC BUILDINGS, 267 Introduction, 267 Foundations, 267 Load-bearing walls, 268 Timber floors, 271 Concrete floors, 272 Timber-frame systems, 275 Roof structures, 277 Chapter 24 DESIGN OF STRUCTURAL ELEMENTS, 281 Introduction, 281 Basic structural concepts, 281 Timber structural elements, 284 Structural elements in reinforced concrete, 288 BIBLIOGRAPHY, 289

Part 6

Introduction Architects and architectural technologists are not expected to be experts in structural engineering, but it is an essential part of their equipment that they should understand the principles involved in selecting and using the components to be assembled into a structure. In the case of simple structures no engineer may be involved, and while traditionally successful methods can generally be relied upon, these will be better appreciated when the mechanics of their behaviour are understood. This involves acquiring a feeling for the way materials behave and a basic sense of both the nature of the forces which will act upon them and the ways in which these can be countered. It is also necessary that the vocabulary of structures should become familiar, so that meaningful interaction with structural engineers and others can take place. Accordingly, this Part of the book introduces, in Chapter 22, the characteristics of the main materials likely to be encountered in simple domestic buildings. Chapter 23 discusses the kinds of structures in which they may be used and some of the elementary concepts of structural mechanics are addressed in Chapter 24, so that the terms and kinds of calculation commonly used are followed. It will be appreciated that both more advanced study and experience will be required before a practitioner should attempt the design of actual components or structures.

Chapter 22

Structural materials I n t ro d u c t i o n The choice of materials is an important part of the design process. Materials would determine the environmental and structural performance of the building as well as its appearance. The environmental performance of the building was discussed previously. This chapter will deal with structural materials, particularly those found in small-span buildings. The first part of the chapter will review some of those materials commonly found in domestic buildings, while the second part will introduce some principles of structures. Although manufacturing processes and raw materials are similar across the world, the characteristics of the materials can vary from one country to another. The materials discussed in this chapter are those available in the UK market.

S t r u c t u ra l m a t e r i a l s Building materials perform a variety of roles. Chief among those is the provision of strength and stability in the form of a structural system for the building of which they form part. This chapter will review a selection of structural materials used in domestic buildings and the general principles behind their structural behaviour. The selection includes: bricks, blocks, concrete and timber.

Clay bricks The use of bricks can be traced back to Roman times. Clay bricks are made from a mixture of finely ground clay and water formed into the

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S T R U C T U R A L C O N S I D E R AT I O N S

required shape and size, which is then dried and fired. The wide range of clay characteristics, combined with various forming processes, can lead to a large variety of bricks. The process of manufacturing bricks is energy intensive and the designer should be made aware of this. The re-use of old bricks is to be encouraged whenever possible as this can lead to saving in both energy and raw materials (clay, water, etc.). The standard size of a metric brick is 215 x 102.5 x 65 mm. When allowing for 10 mm mortar joints, six bricks are equal to one concrete block. That is, three bricks in height and two bricks in length. Apart from the place of origin and type of clay used, bricks are specified according to a combination of descriptions, such as variety, type, appearance, durability and physical properties.

Variety According to variety, there are three classes. Common bricks are suitable for general building work. Their finishes have no particular appeal and they are accordingly used where they will not be visible because render or some other surface finish is likely to be applied. Facing bricks come in attractive finishes and colours, and find their use where a visual effect and a durable finish are required. Engineering bricks have a high density and load bearing capacity and low water absorption. They are used mainly in civil engineering applications. They can also be found in domestic buildings, particularly below the damp proof course.

Type Bricks can also be classified by the presence of voids. According to BS 3921, four classes can be identified: these are solid, cellular, perforated and frogged bricks (see Figure 22.1).

22.1

S T R U C T U R A L M AT E R I A L S

Durability Durability is another criterion according to which bricks are specified. Under this heading, bricks can be classified in terms of frost resistance as well as soluble-salt content. There are three categories according to the frost resistance they provide in a standardised freezing test. The F2 category bricks are totally resistant to repeated freezing and thawing in saturated conditions. Category F1 bricks are resistant to frost except when the freezing and thawing is under saturated conditions. This makes them unsuitable for high-exposure applications, such as below damp proof courses and parapets but they are otherwise suitable for external applications. The classification of bricks by their soluble-salt content is defined by three classes: S2 (low salt content), S1 (normal content)and S0 (no limits to salt content). The presence of soluble salt causes staining, efflorescence and even deterioration of the mortar. If used in exposed areas, the two latter categories of bricks should be laid with sulphate-resisting cement mortar.

Compressive strength Bricks come in a variety of compressive strengths that range from 4 to 180 N/mm2. Different applications would require different strengths. The walls of a two-storey house, for example, would require around 5 N/mm2 strength if built of bricks. For a three-storey house, the outer leaf of the external wall would need to have a strength of 7 N/mm2. The inner leaf would be adequate with a 5 N/mm2 compressive strength for the upper floors and a 15 N/mm2 for the ground floor. In the case of internal walls in brickwork, the strength needs to be 5 N/mm2 in the upper floors and 7 N/mm2 for the ground floor with a thickness of 215 mm. These examples highlight the need to match the required strength to the type of application. For detailed data on design requirements, the reader is advised to consult various national and international design standards and statutory requirements.

Water absorption The water absorption of bricks, which is expressed as a percentage of their dry weight, is critical in certain cases, such as damp proof courses or engineering applications. As well as the water absorption, which can range from 1% to 30% , suction rates are given. With regard to brick laying, low to medium suction rates (up to 2 kg/m 2 per min)are better. A high suction rate can lead to the quick drying out of the mortar, which, in turn, can affect its characteristics.

Moisture and thermal movement The action of moisture absorption from the atmosphere leads to the expansion of bricks in an irreversible movement up to a maximum of

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0.1% of their fired size. To accommodate such movement, expansion joints that allow 1 mm movement per 1 m of brickwork are specified at 10–12 m centres in restrained walls and 7–8 m in unrestrained walls. Similarly, horizontal joints should be specified at 12 m intervals. The joints are filled with easily compressible fillers, such as cellular polythene, foam rubber or polyurethane, which are pointed externally with a sealing compound. Reversible movements caused by thermal expansion are in the order of 0.03% . The coefficient of thermal expansion of typical clay bricks is 5 to 8 x 10-6 K-1. The thermal conductivity of brick is related to its density and moisture content. The conductivity is normally quoted for 5% moisture content (exposed brickwork)and 1% moisture content (protected brickwork). In general, the conductivity of brick varies between 0.65 and 1.95 W/mK.

Fire and acoustic properties Given their manufacturing process, which includes firing at high temperatures, clay bricks have excellent fire resistance and retain their stability and integrity in fire. According to BS 5628-3:2001, a 100 mm load-bearing solid clay brick masonry will give two hours’ fire resistance, while a 200 mm wall would offer six hours’ fire resistance. Given their high density, clay bricks offer a good level of insulation against airborne sound. However, in practice, their performance would depend on the way gaps and voids in the structure are dealt with. A 215 mm single-brick wall plastered on both sides would give an average sound insulation value of 50 dB over the normal building acoustic frequency range (100–3,150 Hz). This would be sufficient to meet current requirements for airborne sound insulation between adjacent buildings. The resistance to impact sound transmission through brickwork is fairly low, particularly if dense plaster is used. The use of acoustic plasters or independent panels of plasterboard combined with absorbent material can improve the impact sound insulation.

C o n c re t e b l o c k s Concrete blocks have become widely used over the last 60 years given their cost advantage over brickwork, particularly when their application does not require good appearance and aesthetics. The wide variety of blocks available on the market today offer a comprehensive range of densities, strength, appearance, size, texture and colour to suit different applications.


Manufacture The density of concrete blocks follows that of the type of aggregates used. Dense concrete blocks are manufactured from natural dense aggregates, such as granite, gravel and limestone. These blocks tend to offer high compressive strength and good sound insulation but, at the same time, the units are heavy to handle and their thermal conductivity is high. Medium and lightweight blocks incorporate lighter aggregates, such as sand expanded clay and pulverised fuel ash. Though their compressive strength is lower than that of dense blocks, they offer better thermal resistance. Once the aggregates are mixed with hot water and cement the concrete is cast into moulds, compacted by pressure or vibration and cured. Aerated blocks are obtained by adding aluminium to a fine mix of sand, lime, fly ash and cement. In the presence of hot water, the aluminium powder reacts with the lime and generates a hydrogen gas. The gas released produces a closed cell structure that gives the blocks a lower density and lower thermal conductivity.

Types and sizes Concrete blocks come in three types: solid, cellular and hollow. Solid blocks have no holes except for slots which are used for cutting. Cellular blocks include one or more cavities that are closed at one end. In the case of hollow blocks, the cavities pass through from one end to another. For these two latter types, the thickness of the external wall must be at least 1.75 times the nominal minimum size of aggregate or 15 mm, whichever is the greater (see Figure 22.2). The standard workface size that corresponds to 2 x 3 bricks is 440 x 215 mm, after allowing for 10 mm mortar joints. Other sizes can be found

22.2

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on the market when aesthetic or constructional reasons dictate. Those sizes include 440 x 140, 440 x 430 and 540 x 440 mm. Most manufacturers produce a selection of thicknesses in the range 50 to 350 mm. Three classes of densities are associated with the three ranges of compressive strength. High-density blocks (1,500–2,100 kg/m 3) have a strength range of 2.8–35 N/mm 2. The compressive strength for medium-density blocks with lightweight aggregate (700–1,500 kg/m 3) is in the range 2.8–10.5 N/mm 2. Autoclaved aerated blocks, for which the density is in the range 400–900 kg/m 3, have strength in the range 2.8–7 N/mm 2. The structural implication of using blocks will be discussed in the next chapter.

Durability Dense concrete blocks and certain aerated blocks have good resistance to freeze/thaw under saturated conditions. This makes them suitable to be used in the external leaves of cavity walls both above and below ground (below the damp proof course), provided their crushing strength is at least 7 N/mm2.

Thermal properties Concrete blocks come with a wide range of thermal conductivities matching that of the concrete densities. At the lower end of the spectrum, low-density aerated blocks can have thermal conductivities in the range 0.1–0.24 W/mK. Medium-density blocks have their conductivities in the range 0.17–0.5 W/mK. High-density blocks conduct heat at a higher rate compared to the other types of blocks. The thermal conductivity range for these blocks is 0.63–1.5 W/mK. Thermal movement is greater in dense aggregate blocks compared to lightweight and aerated blocks. Provided there are no sudden changes to the temperature profile across the two faces of the block, the thermal movement is insignificant.

Fire and sound Blocks provide good resistance to airborne sound insulation. Different forms of construction, ranging from single leaf to cavity wall, can be used to meet current statutory requirements for sound insulation. That said, the mass per unit area of the wall, including the surface finish, needs to be at least 300 kg/m2 for dense concrete blocks and 450 kg/m2 for lightweight blocks. Standard blocks, when used as surface finish, reflect sound and increase reverberation time in enclosures. Acoustic concrete blocks manufactured with a slot lined with an absorbing material are used to control the acoustic conditions. Instead of reflecting


sound energy, they dissipate it. This leads to a reduction in the reverberation time.

C o n c re t e Concrete is a material made from a mixture of cement, aggregates, water and some other additives to control its quality and the manufacturing process. It is, perhaps, the most widely used construction material. It is used either to make building components, such as blocks, bricks, tiles and prefabricated structural elements, or to be cast in situ for various applications. The discussion in the forthcoming sections is not concerned with the engineering aspects of concrete but merely with those relating to its use as a construction material. Well compacted and cured concrete, with adequate quality and amount of constituents, is generally durable. The environment in which concrete exists can subject it to degradation if the conditions favour it. Some of the effects that the environment is likely to have on concrete have been discussed already for blocks. In this section the focus is on those aspects of performance relating to concrete as a structural element in its own right.

Fire resistance This property is as important as the strength of concrete to withstand loading. Concrete that is made from ordinary cement loses its strength within the range of temperatures associated with building fires. At around 600oC little strength of the concrete and its steel reinforcement remains. Though steel and concrete have about the same coefficient of expansion, steel is a good conductor of heat, which means it is likely to fail before concrete, if this latter does not offer enough protection to reinforcements. Under normal building fire conditions, it may take up to four hours for the temperature to reach 650oC below the surface of the concrete. Aggregates play an important role in the performance of concrete in fire. Limestone aggregates perform better in fire compared to crushed rocks such as granites. Concrete with lightweight aggregates performs even better in fire. This is due to the lower thermal conductivities of the aggregates.

Strength Concrete is used primarily for its compressive strength. When reinforced with steel, its usefulness extends to tensile strength as well. This makes it a good structural material. The compressive strength of concrete is specified according to standard classes based on tests carried out on two sets of samples. The first sample is a 150 mm diameter by 300 mm cylinder, and the second sample is a 150 mm cube. There are

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Table 22.1: Compressive strength of concrete in N/mm2 (adapted from Lyons) Dense concrete

Lightweight concrete

Strength category

Cylinder* strength

Cube† strength

C8/10 C12/15 C16/20 C20/25 C25/30 C30/37 C35/45 C40/50 C45/55 C50/60 C55/67 C60/75 C70/85 C70/95 C90/105 C100/115

8 12 16 20 25 30 35 40 45 50 55 60 70 70 90 100

10 15 20 25 30 37 45 50 55 60 67 75 85 95 105 115

LC8/9 LC12/13 LC16/18 LC20/22 LC25/28 LC30/33 LC35/38 LC40/44 LC45/50 LC50/55 LC55/60 LC60/66 LC70/77 LC80/88

Cylinder strength

Cube strength

8 12 16 20 25 30 35 40 45 50 55 60 70 80

9 13 18 22 28 33 38 44 50 55 60 66 77 88

*Cylinder size: 150 mm diameter and 300 mm high †

Cube size: 150 mm

16 classes of strength for dense concrete and 14 for lightweight concrete (see Table 22.1). The tensile strength of concrete is low compared to its compressive strength. Steel is used to reinforce concrete for applications where both compressive and tensile strengths are required. Different types of steel are used in the reinforcements. These include mild steel, hotrolled high-yield steel and high-yield cold-formed steel. The tensile strength for these materials is around 250 N/mm2 for mild steel and 460 N/mm2 for high-yield steel.

Ti m b e r Timber is a material that has been used as long as man has built shelter. Its use is on the increase again because of its environmental credentials. In addition to being increasingly used in the domestic sphere,


it is found in other applications beyond this building sector. Timber and timber-based products offer a number of advantages:

• • • • • •

they are renewable resources, which, when properly managed, would contribute to the reduction of carbon emissions; the energy input into the production of timber-based products is small compared to other building materials; timber has a good appearance and a warm feel because of its low thermal conductivity; timber has a high strength to weight ratio; as a material, timber is easily worked and strongly joined;and structural timber has good fire resistance.

On the other hand, when using timber, it is worth bearing in mind the following issues:

• • •

the characteristics of the timber can be variable due to the presence of natural imperfections, such as knots and shakes; changes in moisture content can lead to movement, distortion and creep under load;and timber can be subjected to attack from natural agents, such as fungi and insects.

Strength of timber This is a property most useful when considering the use of timber, particularly for structural purposes. According to BS EN 338:2003, there are 15 strength classes. Nine of those categories cover softwood timbers, ranging from C14 to C40, and six categories describe hardwood timbers and range from D30 to D70. Table 22.2, which is based on the British Standard mentioned above, gives a selection of strength properties for those classes.

Fire resistance Timber is organic in nature, which makes it a combustible material. However, when used in large sections, such as structural ones, it performs better in a fire compared to equivalent sections of steel or aluminium. To explain this performance, the behaviour of timber in fire is outlined. Given that timber has a low thermal conductivity, its surface heats up quickly which makes it burn readily. The rate at which the burning process takes place depends mainly on the thickness of the timber member. The burning rate in large structural sections is slow. This can be explained by the formation of a charcoal layer on the surface of the section, which acts as an insulator for the core. This is helped further by the evaporation of moisture from the surface, which is then partly diffused inwards. This helps slow the rate of the burning of the core.

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Table 22.2: Strength classes for timber (adapted from Lyons) Characteristic value

Strength class Coniferous softwood

Deciduous hardwoods

C14

C16

C18

C22

C24

C27

C30

C35

C40

D30

D35

D40

D50

D60

BS EN 338 B E1 parallel ρ average

14 7 350

16 8 370

18 9 380

22 10 410

24 11 420

27 12 450

30 12 460

35 13 480

40 14 500

30 10 640

35 10 670

40 11 700

50 14 780

60 70 17 20 840 1,080

BS 5268 B parallel E2 parallel

4.1 4.6

5.3 5.8

5.8 6.0

6.8 6.5

7.5 7.2

10 8.2

11 8.2

12 9.0

13 10.0

9 6.0

11 6.5

12.5 16 18 23 7.5 12.6 15.6 18.0

Key: B E1 parallel ρ average B parallel E2 parallel

D70

Bending N ( /mm 2) Mean modulus of elasticity parallel to the grain N ( /mm 2) Average density k( g/m 3) Bending parallel to the grain (N/mm 2) Minimum modulus of elasticity parallel to the grain (N/mm 2)

The surface of the timber can be treated with fire-retardants which are inorganic chemicals that produce non-combustible gases when heated and hence reduce flaming. Another method of surface treatment is the application of intumescent coatings. Untreated timber has a Class 3 fire resistance, which can be upgraded to Class 1 by surface treatment.

S t r u c t u ra l p r i n c i p l e s Force Isaac Newton observed the apple falling from the tree under its own weight due to earth’s gravitational pull (gravity). The force moving the apple is measured in newtons (N). The definition of the newton is the force which, when applied to a body with a mass of 1 kg, will cause an acceleration of 1 metre per second per second m ( /s 2.) Since the earth’s gravity is 9.81 m/s2, a mass of 1 kg will produce a force of 9.81 N. For everyday structural calculations, this is equated to 10 N.


Moment A moment is the ‘rotational’ effect of a force applied at a point on a body that is likely to rotate at a point some distance away from the force. The moment is equal to the force multiplied by the distance (see Figure 22.3).The unit of a moment is kilonewton metres (kN.m)or newton millimetres (N.mm). To convert from kN.m to N.mm you have to multiply by 1,000,000 (1,000 for kN to N and 1,000 for m to mm). 22.3

Stress and strain Stress can be referred to as the intensity of the external force acting on a body, while the strain is the deformation that takes place in the body as a result of the stress. The former is equivalent to the force divided by the cross-sectional area of the body and has its unit as N/mm2. The latter equals the change in shape over the original shape (see Figure 22.4)and is a dimensionless factor. A pulling force will cause a tensile stress, while a crushing force will yield a compressive stress.

Elastic and plastic behaviour Structural materials need to be elastic to be suitable for the purpose. An elastic state of the material is when it deflects under load and recovers to its original form when the load is lifted. Imagine a floor joist that does not return to its original shape after a load has been applied and removed, and permanent p ( lastic)deformation has occurred. Every time the load is applied, the same deformation will happen time and time again. After a while the deformation will reach a point when the joist will collapse. In practice, structural materials behave elastically up to a certain point, which is the limit of the elastic region. When materials are used structurally, the loads need to be kept within the elastic range. Those loads fall in one of two categories: primary and secondary ones.

Primary loads The primary loads that a building must be able to resist can be categorised into the following:

• •

•

Dead load –this is the weight of the building (both structure and fabric).The dead load of a building does not change as long as the building has not been altered significantly. Imposed load –this is also known as live load. It refers to any moveable objects inside the building, including people and furniture. When designing buildings, the use of the building and any future changes need to be borne in mind, as they would affect the imposed loads. Snow load –the load that snow can impose on the roof of a building depends on the climatic conditions as well as the roof shape (whether flat or sloping).

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•

Wind loads –consideration of wind loads is particularly important if lightweight forms of construction are used or if the site is highly exposed to strong winds. A particular aspect of wind loading that needs consideration is lateral bracing to withstand wind.

Secondary loads Such loads could be thought of as internal loads resulting from the behaviour of materials over time. They include the following:

•

•

• •

Moisture-induced loads –building materials, over time, can lose or gain moisture and can shrink or expand accordingly. If they are restrained, the movement will induce loads that can lead to cracking. The use of joints and the right combination of materials can reduce this loading. For instance, combining clay bricks within a reinforced concrete frame can lead to the wall bowing outward as the bricks expand and concrete shrinks. Thermal loads –building materials expand and contract as their temperature changes. For this reason, expansion joints are used in big structures. Different materials would require joints at different intervals (see the previous materials section). Settlement loads –when one part of a building is heavier than another differential settlement will occur and cracking will follow unless the two parts are separated or joined flexibly. Dynamic loads –these are loads which can be induced by either natural conditions (wind blowing over a tall lightweight chimney stack) or operational ones, as in the case of vibration-induced loads from machinery. The solution to these loads is normally to reduce the dynamic effect of the forces (spiral strake for the chimney or anti-vibration mounts for machinery).

Chapter 23

Structures for domestic buildings I n t ro d u c t i o n The choice of a structural system is part of the integrated design process and affects a number of aspects of the building being designed. Apart from the structural performance itself, such aspects include: space planning, form and shape, other materials for the fabric, cost as well as environmental performance. This chapter will discuss some of the commonly used structural components and systems used in dwellings. The discussion is not meant to be a comprehensive survey of structural systems but, rather, an overview of some of the structural components.

Foundations The foundations of a building transmit all the loads acting on it (dead, live, etc.)to the ground in a safe manner that is compatible with the load-bearing capacity of the ground. The choice of any particular type of foundation is determined by the loads of the building, the type of soil, type of mechanical plant available and by other economic factors. The following sections will discuss some of the most common types of foundations used in domestic buildings. Usually the choice of foundation is a decision taken after a site investigation has been carried out. The architects would work closely with the structural engineer, whose job is to design the structural system including the foundations sizing. Strip foundation is a common form of foundation in dwellings. The load-bearing walls, including the internal ones, sit on a strip of concrete. The width of the strip can be worked out roughly from knowledge of the building loads and the load-bearing capacity of the ground. The

268


23.1

example above demonstrates this. A two-storey house with load-bearing walls has a total building load of 50 kN/m run of load-bearing wall. A strip foundation was the type of foundation desired. The ground has a load-bearing capacity of 85 kN/m2. In this case, the width of the strip is worked out as shown in the diagram in Figure 23.1. It was found to be 0.588 m, which in practice would be rounded up to 600 mm. The thickness of the strip is chosen in a way to resist shear forces. To achieve this, the thickness of the strip needs to be, at least, equal to the projection of the strip beyond the edge of the load-bearing wall or 150 mm, whichever is the greatest. An alternative solution to a deep strip is to reinforce the thin strip with steel bars running along and across it. If there are no trees near the building and the soil is compact sand/gravel, a trench depth of 450– 500 mm would be enough. This depth needs to be increased up to 1 mm which is, in any case, desirable to remove the danger of frost damage. Beyond this depth; the strip foundation becomes uneconomical. Under these circumstances, a pile foundation may be more suitable. For detailed guidance on the effect of the tree proximity on trench depth, reference should be made to BRE Digest 298. On sloping sites, the foundation needs to be stepped up for it to be economical. For further details on the rules governing this type of foundation, guidance should be sought from the Building Regulations Approved Document.

Load-bearing walls Most orthogonal structural systems comprise horizontal and vertical elements. Horizontal structural elements, such as beams, joists and

STRUCTURES FOR DOMESTIC BUILDINGS

rafters, need to have good tensile strength. Vertical structural elements, such as columns and walls, need to resist compressive loads. Since building materials tend to have enough compressive strength, it remains that the choice of one system or another depends, primarily, on the spans that horizontal elements need to cover. In domestic buildings, one of the widely used systems is that of loadbearing walls. These can be either solid construction or of the cavity type. If such a system is adopted, the following points need to be borne in mind:

• •

•

• • • •

The size of rooms and structural spans are dictated by the size of joists or beams. If timber floors are used, the maximum span that can be achieved is around 6 m. Most dwellings would require spans less than this. If such a floor is used, masonry load-bearing partitions on the upper floors need to be above those on the ground floor. If solid load-bearing walls are used, say in conjunction with an external lightweight cladding, the thickness of the masonry walls is stepped, reducing towards the top. This improves the stability and reduces the redundant parts of the wall, as the loads imposed at the top are less than those at the bottom (see Figure 23.2). The use of this type of structure reduces the economic width of openings i(.e. windows), which otherwise would need very deep lintels. In a conventional cavity masonry wall, the loads of floors and roof are usually supported by the inner leaf. Lateral restraint for the walls is provided by the timber joists and the bonding of internal partitions (see Figure 23.3). If concrete floors are used, longer spans can be adopted within economic depths of beams and slabs (up to 8 m for a 200 mm deep beam). When this type of floor is used, masonry partitions on upper levels can be supported by the floor.

23.3

23.2

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270


23.4

One of the issues that affect the stability of a load-bearing wall is its effective width. For a cavity wall construction, the effective width is based on an estimate that takes into account the thickness of both leaves and the bonding between them. A good rule of thumb is that shown in Figure 23.4. The other structural problem that a designer needs to consider, without the complicated engineering calculations, is the eccentricity of the load at the top of the wall. If joists are hung onto the wall using hangers, the load is considered axial if the point at which the load is acting on the wall is within 5% of the centre of the wall (see Figure 23.5). When load-bearing walls are used, the size of openings and their locations in the external walls need to be carefully considered. Detail advice on this topic can be sought from the Building Regulations Approved Document A: 2004.

23.5


Ti m b e r f l o o r s In modern house construction, ground floors constructed of timber are not very common. This is more to do with economics rather than technical or other issues. There is no reason why these cannot be used. When used with masonry load-bearing walls, the following points need to be considered:

• • • • •

the ground needs to be covered with a layer of concrete laid over hardcore with a damp proof membrane; the floor joists need to be suspended in such a way that air can circulate below them (at least 150 mm between the bottom of joists and top of concrete); ventilation of the under-floor should be provided by means of air bricks; insulation is installed between the joists to satisfy current requirements (see Figure 23.6);and in semi-detached and terraced dwellings, it is better for sound insulation reasons to span the joists parallel to the party wall.

For upper floors, timber floor construction is used typically in singleoccupation dwellings (house)where there is less need for sound insulation. In blocks of flats, there is a tendency to use concrete floors. For both ground and upper floors, the size of the joists is set out in the Building Regulations. As a general rule, joists are 50 mm wide by 150 mm deep or 50 mm wide by 200 mm deep. While the former would give a span of around 3.3 m, the latter would span up to 4.5 m. While

23.6

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272


23.7

the depth of a joist is directly related to its span, the width does not affect the span but rather the resistance to twisting. Strutting is used, either in off cuts or herringbone, to stop the joists from twisting and to add stiffness to the whole structure. Joists are, normally, spaced at 400 mm centres. This distance is used as a module on which most floor covering and ceiling boards are based. Joists can either be built into the inner leaf of the wall or hung off it using galvanised or stainless steel hangers. If the first method is used, care needs to be taken to avoid having the joists affected by the cold outside leaf or any water vapour in the cavity. If the second method is used, then the issue of eccentricity, as explained above, needs to be considered. A typical modern timber floor layout is shown in Figure 23.7.

C o n c re t e f l o o r s The use of concrete floors in the construction of dwellings in the UK saw a massive increase after the second world war. It came as a response to the shortages in both timber and skilled labour needed to cope with the huge demand for housing. Nowadays most dwellings have their ground floors in concrete. In the case of blocks of flats, most of the floors (ground and upper floors)in newly built ones have concrete floors. This form of construction offers a number of economic advantages over timber floors. These floors can be used in combination with different structural systems. According to their type, they can be subdivided into two categories: ground-supported floors and suspended floors. A ground-bearing floor slab is supported directly by the ground beneath it. As it is not tied to the external walls, differential settlement


is easily accommodated. Over the years, the construction of this type of floor has evolved to incorporate modern standards of thermal insulation, damp proofing and radon protection. Modern groundbearing slabs are constructed in a variety of ways which differ mainly in the position of both the damp proof membrane and the insulating layer. One of these is described in Figure 23.8. For reasons of unsuitable subsoil or the presence of a slope, a layer of hardcore is used. This needs to be compacted very well in layers 200 mm thick. If the total thickness of the hardcore is likely to be more than 500–600 mm it is more economical to opt for a suspended floor. If the damp proof membrane is to be laid below the concrete slab, it needs to be protected from puncture by a layer of blinding sand. In this case, the membrane, which is usually a polythene sheet, doubles up as a radon protection layer as well. Having the damp proof membrane below the concrete slab has its advantages. Once the fresh concrete has dried up and the water evaporated, its moisture content would remain almost constant, which means less moisture movement. If the concrete is cast during the warm season, the presence of the membrane underneath it would eliminate the moisture loss to the hardcore. If this loss occurs, it could lead to cracking of the concrete. The concrete slab is usually around 100 mm thick. Normally the concrete is not reinforced, unless the ground conditions require it. In such a case, a steel mesh is used as reinforcement. The position of the insulation with respect to the concrete slab depends on the heating and overall environmental strategy for the building. For instance, if the floor is used for its thermal mass as heat sink, it would be better to have the insulation below the slab. The same would be true if under-floor heating is used. If, on the other hand, the building is required to have a fast thermal response, the insulation should be placed above the slab. Regardless of where the insulation is placed, a layer of screed is required to finish off the floor. When designing the floor details, care should be taken in dealing with cold bridging and the provision of a continuous barrier to rising damp. Suspended concrete floors are, sometimes, used for the ground floor construction. Their main use, however, is for upper floors. Regardless of which application they are used for, the principles governing their construction are the same. Although they can be cast on site, this process is used mainly for large-scale buildings. In the case of houses, prefabricated concrete floors are more economical to use. A number of beam and block systems can be found in use around the world. They tend to be similar, with some minor changes to suit local manufacturing methods. One of the systems widely used in the UK is the inverted T ‘ ’ beam and block floor. The beams are pre-cast in the factory and delivered on site ready to be lifted into place. The beams can be cast in 150 mm and 200 mm depth to suit different loading conditions. The beams

23.8

273

274


23.9

have steel bar reinforcements and can span up to 8 m. According to the overall structural system being used, they can be supported by the loadbearing walls or the main structural beams spanning between the columns. In the case of load-bearing walls, the inverted ‘T’ beams sit on the inner leaf of a cavity wall and they require 100 mm bearing. If they are supported on internal load-bearing walls at one end, they need to overlap in order to have the required bearing surface. The spacing of the beams is dictated by the size of the blocks of hollow concrete pots that slot between them to form the floor deck. A layer of screed is laid over the surface to fill any gaps and to form a level surface that can receive the floor finish. If the floor requires sound insulation, the floor finish is separated from the screed by a resilient layer. Such a floor finish is referred to as a floating floor. A typical example of an inverted ‘T’ beam and block floor is shown in Figure 23.9. A second type of suspended concrete floor is the pre-cast concrete plank floor. In this system, instead of beams supporting blocks between them, the floor deck is formed by pre-cast lightweight reinforced concrete planks, which are supported by the load-bearing walls (or the main structural beams) in the same way as the inverted ‘T’ beams explained above. Similar floor finishes to those referred to earlier can be used with the planks. Given that the planks are built into the wall in both the transverse and axial directions, they provide more restraint to the walls than that given by the inverted beams. Suspended concrete floors offer a number of advantages as they cover longer spans and require little on site work. On the other hand, their flexibility is limited compared to timber joists, which can be cut to size on site. To take full advantage of what these floors can offer, the decision regarding the choice of floor system needs to be considered early on in


Table 23.1: Approximate depths of various structural elements (after Gauld) Type of member

Depth

Beam Slab Cantilever Truss

Span/20 – span/18 Span/30 Depth at fixed end: span/7 Span/14

the design process. This would enable the design to be optimised in terms of spans. The more standardised the spans are, for instance, the quicker and more cost-effective the prefabrication of the floor system would be. Table 23.1 shows approximate sizes of structural members.

Ti m b e r- f ra m e s y s t e m s Timber was the most commonly used structural material in the UK for centuries. Timber framed buildings of the late fifteenth and sixteenth centuries are a testament to that. In those days, the construction consisted of a timber hardwood frame with infill of wattle and daub or other local materials. The Great Fire of London and the changes to building legislation that followed has lead to the development of brick as a construction material and to the decline of traditional timberframed houses built of heavy oak. Modern timber-framed buildings are completely different to their traditional predecessors. They were developed from softwood timber based on methods originating from North America and Scandinavia where this material is in abundance. The use of timber as a structural and building material offers a number of advantages, particularly from an environmental point of view. It is a renewable resource, particularly if it is sourced from environmentally managed forests. Timber, when being grown, contributes to the reduction of carbon dioxide in the atmosphere. Furthermore, timber has low embodied energy and a low thermal conductivity, which makes it ideal for buildings in cold climates. This form of construction offers the economic advantage of prefabricated components with the flexibility of a modular system. Modern timber-frame building systems fall in one of two categories: platform frame and balloon frame. The main difference between the two being the way the floors are fixed to or onto the walls. In a platform frame, which is the subject of this analysis, each floor is treated

275

276


as a separate construction. The floors in timber-framed buildings are constructed in the same way described previously for timber floors used with load-bearing masonry construction systems (Figure 23.10). Although most modern timber-framed houses are indistinguishable from brick houses due to the external leaf of brickwork common to both types, timber-frame construction can be used in a variety of ways:

• • • •

an insulated internal timber-frame combined with an external leaf of masonry; two insulated frames side by side, with the outer one clad for rain screening; two separate frames as above, with a cavity in between to increase the level of thermal insulation;and one single wide frame with external cladding and internal finish.

These types of construction are illustrated in Figure 23.11. 23.10

Regardless of the type used, the principles of panel design and fixing are similar. Although panels can be made up on site, it is more economical to have them prefabricated and delivered on site ready for lifting into place. Panels are modular in size, with a single-storey height (2.4 m)and lengths as a multiple of 1.2 m up to 3.6 m. If lifting cranes are used on site, even larger panels can be made. Each panel consists of a bottom rail, a top rail and vertical studs at 600 mm centres. The panel is sheathed on the outside with a sheeting material, such as strand board or plywood. Insulation is installed in the frame with an internal panel of plasterboard. The thickness of the studs varies according to the need for insulation. The panels are fixed to a sole plate and to a header binder that runs round the perimeter. Lateral restraint is provided by both the stiffness of the sheeting and the binders in one direction. In the other direction, this is provided by the partitions and floor joists. Figure 23.12 shows the main components of a timber-frame construction.

23.11


23.12

R o o f s t r u c t u re s Roofs, in general, can be designated either as flat or as pitched. Domestic buildings, apart from blocks of flats and apartments, tend to have pitched roofs. These come in a wide variety, ranging from a single pitched to a double pitched and from hipped roofs to mansard ones. All these traditional roof constructions use heavy timber members and tend to impose heavy loads on the walls. Modern pitched roofs tend to be constructed from trussed rafters. These are prefabricated in the factory and are delivered to site ready for lifting into place. Given the triangulation of trusses, these can cover wider spans for comparatively small-size timber members. The timbers are typically 80 x 40 mm in section and the resulting truss can span up to 11 m (see Figure 23.13). Compared to traditional roof construction, modern roof trusses offer a number of advantages:

23.13

277

278


• • •

given their large spans, there is no need for load-bearing partitions to support them; they offer a relatively cheap and fast construction method, with little or no need for skilled labour;and they can be designed and prefabricated to suit various applications, provided that the supplier gets all the information regarding the building.

The main drawback that this roof construction has, in comparison to traditional roofs, is the limited use of storage space in the loft. This is due to the presence of compression and tension members of the truss. The trusses can be used in the same way as floor joists to give the walls lateral restraint.

On-site fixing Although the trusses are prefabricated, they still require some on-site work to fix them in place. The designer is often called upon to devise some of the detailing required to carry out the work. Hence, this short discussion of the method of putting up the trusses. These are usually fixed at 600 mm centres. The fixing method is by means of a wall plate fixed to the inner leaf to which the truss is fixed using either nails, screws or truss clips (see Figure 23.14). In order to give the roof structure rigidity and to provide the load-bearing walls with restraint, two methods of fixing are used: the binding of rafters and the strapping of trusses to the gable end. Timber binders, usually of 100 x 25 mm sections are used to tie the trusses and hold them together. For spans up to 8 m, three binders are used. For larger spans up to 11 m, five binders are used. The binders can be lapped over two trusses, if they are not of sufficient length from one gable end to another. Now that the roof structure is a single unit, it needs fixing to the gable ends to provide the supporting walls with restraint to resist

23.14


23.15

wind loading. Galvanised steel straps are used to tie back the rafters at 2 m intervals. The straps should cross at least two rafters. If the roof is steep, there is a need to strap the joists to the gable end in the same way (Figure 23.15). Detailed advice on the strapping of the roof structure can be sought from the Building Regulations.

279

Chapter 24

Design of structural elements I n t ro d u c t i o n Structural design is a very specialised field of engineering related to the design and construction of buildings. It is carried out by a structural engineer who forms part of the design team. From the point of view of the architect, the technologist or the surveyor having an appreciation of what the design of a structural system involves can make their task easier. On small-scale projects, the structural calculations can be carried out by an architect or a technologist if they happen to have some training in doing so. The two previous chapters discussed some of the characteristics of structural materials and components/systems. Having done that, it is felt that the reader would benefit from an introduction to some structural concepts and the calculations associated with some of them.

B a s i c s t r u c t u ra l c o n c e p t s Horizontal structural elements, such as beams and joists, are designed to support loads acting on them. The action of the loads will generate reactions at the points where the beam, for instance, is supported. Furthermore, the beam must be designed to resist those loads. It does that by developing bending moments and shear forces. When a beam (see Figure 24.1)is under load, its top half will be under compression and the uppermost fibres will be the shortest. On the other hand, the lower half of the beam will be under tension and the lowermost fibres will be the longest. For any given beam, if the loads acting on it and the conditions of its supports are known, both bending moments and shear forces can be calculated using standard mathematical equations

282


24.1

24.2

as those given in Table 24.1. In order to determine the shear forces acting on the beam, the reactions at the supports need to be determined. If the beam shown in Figure 24.2 is assumed to have a span of 4 m and a uniformly distributed load of 2 kN/m, the following can be deduced about the reactions at the supports:

• • •

the total force acting on the beam is equal to 2 kN/m times 4 m which is 8 kN. This force has the same effect of a single load of 8 kN applied at the middle of the span; the sum of the two reactions at the supports (acting upwards)is equal to the total load 8 kN;and since the load is acting on the middle of the span, the two reactions are equal, RA =R B =4 kN.

DESIGN OF STRUCTURAL ELEMENTS

Table 24.1: Basic structural behaviour of various configurations of a simply supported beam

Uniformly distributed loads

Point loads

Beam

Bending moment

Shear force

Maximum deflection

283

284


24.3

In another case, the load on the beam is to be a concentrated load of 5 kN, located at a distance of 1.5 m from support A and 2.5 m from support B (see Figure 24.3).The reactions R A and RB will be proportional to their distances from the load. In this case: æ 2.5 m ö ÷ ´ 5 kN = 3.125 kN RA = çç ÷ è 4m ø

RB

1.5 m 4m

5 kN 1. 875 kN

To demonstrate how bending moments and shear forces are dealt with, the following example is given. A three-storey terraced house has its ground floor being converted into a shop s( ee Figure 24.4).The new shop front requires a large opening which takes up most of the wall area. This required the load-bearing wall on the ground floor to be replaced by a reinforced-concrete beam that takes up the loads of the building. The various loads acting on the beam (beam’s own weight, dead loads, imposed loads, etc.)were calculated and found to be 309 kN. Given that the span of the beam is 4.5 m, this gives a uniformly distributed load equivalent to 69 kN/m 3 ( 09 kN/4.5 m =69 kN/m). At this stage, we need to know the bending moments and shear forces generated within the beam. The solutions are shown in a diagrammatical form in Figure 24.5.

Ti m b e r s t r u c t u ra l e l e m e n t s The use of timber elements as structural components covers both flexural members (beams/joists, etc.)and compression members when they are used as columns.


24.4

24.5

In the case of beams and other horizontal structural elements, a number of aspects related to their specific performance are considered as part of the structural design. The first of these is the lateral stability of beams and joists. Given these elements are usually fixed at their ends and often braced with off cuts, they have sufficient lateral restraint, provided that the ratio of depth to breath does not exceed 5.

285

286


The sizing of timber beams based on the dead and imposed loads offers scope for even higher short-term loading. For instance, to accommodate snow loading, the loading capacity of the timber beams based on dead and imposed loads can be incremented by 25% . When both wind and snow are considered, the basic loading capacity is incremented by 50% . An important aspect of the structural behaviour of timber beams is their flexural strength. The bending moments in a beam, explained earlier, the stress induced in it, and its stiffness are all related to each other as shown in the following equation:

f =

M Z

where f =stress, M =bending moment and Z =section modulus of the beam. The section modulus for a rectangular section with a breath b and depth d is given by the formula:

Z

b d2 6

Once the stress is determined for the loading conditions, it is compared to the permissible bending stress for the particular grade of timber used. Such data can be obtained from British Standard BS 5268: Part 2. The other aspect of performance that the timber beam or joist needs to be checked for is its deflection. This is the change in the length of the fibres that are stretched under loading at the lowermost of the beam section.The actual deflection under the loading conditions is given by the appropriate equation from Table 24.1 a ( dapted from Gauld, 1984).This is then compared to the permissible deflection given by the equation:

D

0.003 L

where D =permissible deflection m ( m)and

L =span of beam/joist m ( m).

To demonstrate how these aspects of timber-beam performance are dealt with the following example is given. In the example of the terraced house used previously, timber joists are used in the transverse direction to support the floors. The joists have a section of 50 mm by 200 mm and a span of 4.5 m at 400 mm centres. It is required to check the stresses and deflections of the timber floor joists at the first floor level.

Step 1: Determine the loading on the joist This is usually carried out using design tables. Such tables can be found in BS 6398 and BS 648. For the purpose of this example the following loads are used:


• • •

imposed loads (domestic)=1.5 kN/m 2; dead loads (including joist self-weight)=0.5 kN/m 2;and total load on 1 joist =(1.5 kN +0.5 kN)x 4.5 m (span)x 0.4 m (spacing), this gives a total load of 3.6 kN.

Step 2: Determine the maximum bending moment The maximum bending moment, according to Table 24.1, is given as W x L/8. In this case, W equals 3.6 kN (from step 1)and L is 4.5 m (span). This gives a maximum bending moment of 3.6 x 4.5/8, which equals 2.025 kN.m.

Step 3: Checking of flexural stress in the joist

•

The section modulus is given by the equation:

Z =

•

with b being 50 mm and d being 200 mm. Putting these values into the equation gives a value for Z as 333 x 103 mm3. The actual flexural stress on the joist is given as:

f

•

b ´d 2 6

M Z

Substituting for the values of the bending moment M and the section modulus Z, f is found to be 6.08 N/mm2. According to BS 5268: Part 2, a joist with a section 50 mm by 200 mm would have a bending stress of 6.8 N/mm2 if it is C22 Class. This would be the minimum class that can be used in this case.

Step 4: Checking the deflection of the joist

• •

The permissible deflection is calculated as 0.003 x 4,500 mm (span)and this is equal to 13.5 mm. The actual deflection (from Table 24.1)is given as:

Deflection

•

5 W L3 384 E I

The various terms in the equation are given as follows: — W is the total load on the joist, 3.6 kN or 3,600 N; — L is the span of the joist, 4.5 m or 4,500 mm; 2 — E is the modulus of elasticity of the timber, 9,700 N/mm ;and — I is the second moment of area, given as:

I

b d 32 12

(see the calculation of Z in Step 3 above)

287

288


In this case:

I =

•

50 ´ 200 3 = 33.3 ´ 10 6 m4 12

When all the terms are substituted into the equation above, the actual deflection is calculated as:

Deflection

•

5 384

3,600 4,500 3 9, 700 33, 300,000

13.22 mm

The actual deflection is lower than the permissible deflection (13.22

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