OFF SITE MANUFACTURE AND MODULAR CONSTRUCTION THE FUTURE OF
HOUSE BUILDING?
submitted by William Clayton
for the MSc in Quantity Surveying
at London South Bank University
Faculty of Engineering, Science and Built Environment
Department of Property, Surveying and Construction
year 2007
Restrictions on use
This dissertation may be made available for consultation within
London South Bank University and may be photocopied or lent to
other libraries for the purposes of clarification.
Signed:
William Clayton
(William Clayton)
Authors declaration
I declare that this dissertation is my own unaided work except
where specifically referenced to the work of others.
Signed:
William Clayton
(William Clayton)
Acknowledgements
The author would like to thank the following people for their
support and assistance during the course of undertaking this
dissertation:
Ben Kennedy Marketing Project Manager, Urban Splash
Gordon Callaway Group Policy Manager, Hyde Housing
Association
Susan May Principal Development Manager, The Peabody Trust.
Keith Tweedy Senior Lecturer, London South Bank University
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Contents
CONTENTS Page
Contents
3
List of Tables and Figures
7
Abstract
10
1
Introduction 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Scope of
Chapter Rationale Aim Objectives Research Questions Assumptions
Outline Methodology Dissertation Structure Chapter Appraisal 11 11
13 13 13 14 15 16 17
2
Off-site manufacture A History in Construction 2.1 2.2 2.3 2.4
2.5 2.6 Scope of Chapter Definition of the Terms Origins of
Off-site manufacture in the United Kingdom 1914 1939 1939 onwards
Large-panel high-rise residential buildings 2.6.1 2.6.2 2.7 2.8
Ronan Point, Newham, East London Other problems with high-rise LPS
systems 18 18 21 22 23 24 25 25 27 27 27 28 30
Non-Domestic Applications Policy Agenda 2.8.1 2.8.2 The Latham
Report The Egan Report
2.9
Chapter Appraisal
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William Clayton (No. 2402164) Contents
Page 3 Off-site manufacture Current Applications and
Implications for Future Use 3.1 3.2 3.3 3.4 Scope of Chapter The
Current Situation Benefits of Off-site manufacture Barriers to
Application 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 3.4.6 3.5 3.6 General
Image Perceived Performance Customer Expectation Perceived Value
Industry Culture Product Awareness 31 31 33 35 35 35 36 36 37 37 38
39
Applications for Future Use Chapter Appraisal
4
Successful Projects Using Off-site Manufacture 4.1 4.2 Scope of
Chapter Successful Projects using Off-site Manufacture 4.2.1 4.2.2
4.2.3 4.2.4 4.2.5 4.3 Moho Urban Splash Barling Court Hyde Housing
Association Corbet House Hyde Housing Association Murray Grove The
Peabody Trust Barons Court The Peabody Trust 41 41 42 43 45 47 49
51
Chapter Appraisal
5
Research Design and Methodology 5.1 5.2 5.3 5.4 5.5 5.6 5.7
Scope of Chapter Statement of Research Aim Research Strategy
Rationale of the Research Questionnaire Rationale of the Interviews
The Research Sample Method of Analysis 53 53 54 55 59 61 62
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William Clayton (No. 2402164) Contents
Page 5.8 Chapter Appraisal 62
6
Data Analysis and Results Detailed Analysis 6.1 6.2 6.3 Scope of
Chapter Detailed Analysis Moho Urban Splash Detailed Analysis
Barling Court Hyde Housing Association 6.4 Detailed Analysis Corbet
House Hyde Housing Association 6.5 Detailed Analysis Murray Grove
The Peabody Trust 6.6 Detailed Analysis Barons Place The Peabody
Trust 6.7 Chapter Appraisal 101 94 88 81 64 64 74
7
Data Analysis and Results Benchmarking 7.1 7.2 7.3 7.4 7.5 Scope
of Chapter Benchmarking Key Performance Indicators Assessment of
the Construction Programme Assessment of the Construction Costs
Chapter Appraisal 102 102 112 114 116
8
Conclusions and Recommendations 8.1 8.2 8.3 8.4 Scope of Chapter
Limitations Research Questions / Objectives Summary of Key Findings
/ Recommendations 118 118 120 122
References
124
Appendix 1 Appendix 2 Appendix 3 Appendix 4
Blank Questionnaire Questionnaire Response from Urban Splash
Questionnaire Response from Hyde Housing Association Questionnaire
Response from The Peabody Trust
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William Clayton (No. 2402164) Contents
Appendix 5 Appendix 6
Variables Affecting BCIS Estimated Construction Time Variables
Affecting BCIS Average Prices
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William Clayton (No. 2402164) List of Tables and Figures
LIST OF TABLES AND FIGURES
Tables
Page
Table 6.2.1
Comparison of Construction Cost and Programme for the Moho
development
73
Table 6.3.1
Comparison of Construction Cost and Programme for the Barling
Court development
81
Table 6.4.1
Comparison of Construction Cost and Programme for the Corbet
House development
87
Table 6.5.1
Comparison of Construction Cost and Programme for the Murray
Grove development
94
Table 6.6.1
Comparison of Construction Cost and Programme for the Barons
Place development
101
Table 7.3.1
Variables affecting the BCIS Estimated Construction Time
113
Table 7.4.1
Variables affecting the BCIS Mean Construction Cost
115
Figures Figure 1 Off-site Manufacture and its related techniques
21
Figure 4.1 Figure 4.2
Urban Splashs Moho Development Hyde Housing Associations Barling
Court Development
42 44
Figure 4.3
Hyde Housing Associations Corbet House Development
46
Figure 4.4 Figure 4.5
The Peabody Trusts Murray Grove Development The Peabody Trusts
Barons Place Development
48 50
Figure 6.2.1 Figure 6.2.2 Figure 6.2.3 Figure 6.2.4
Moho location plan Construction of a unit at the Moho
Development Computer generated image of a completed unit
Significant factors in choosing modular construction for the Moho
project
65 66 66 68
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) List of Tables and Figures
Page Figure 6.2.5 Benefits of off-site manufacture and their
significance to the Moho project Figure 6.2.6 Figure 6.2.7 Figure
6.2.8 The Moho modules under construction in the factory A
completed Moho unit Barriers to adoption of off-site construction
and their affect on the Moho project 70 70 72 69
Figure 6.3.1 Figure 6.3.2 Figure 6.3.3
Barling Court location plan Barling Court Typical Floor Plan
Significant factors in choosing modular construction for the
Barling Court project
74 75 76
Figure 6.3.4 Figure 6.3.5
The exterior of Barling Court Benefits of off-site manufacture
and their significance to the Barling Court project
78 79
Figure 6.3.6
Barriers to adoption of off-site construction and their affect
on the Barling Court project
80
Figure 6.4.1 Figure 6.4.2 Figure 6.4.3
Corbet House location plan Diagrammatic construction of the BUMA
system Significant factors in choosing modular construction for the
Corbet House project
82 83 84
Figure 6.4.4
Benefits of off-site manufacture and their significance to the
Corbet House project
85
Figure 6.4.5 Figure 6.4.6
A typical bathroom at the Corbet House development Barriers to
adoption of off-site construction and their affect on the Corbet
House project
86 86
Figure 6.5.1 Figure 6.5.2 Figure 6.5.3
Murray Grove location plan The stacking style construction of
Murray Grove Significant factors in choosing modular construction
for the Murray Grove project
88 90 90
Figure 6.5.4
Benefits of off-site manufacture and their significance to the
Murray Grove project
91
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) List of Tables and Figures
Page Figure 6.5.5 Barriers to adoption of off-site construction
and their affect on the Murray Grove project Figure 6.5.6 The
Murray Grove development 93 92
Figure 6.6.1 Figure 6.6.2
Barons Place location plan Significant factors in choosing
modular construction for the Barons Place project
95 97
Figure 6.6.3
Benefits of off-site manufacture and their significance to the
Barons Place project
98
Figure 6.6.4 Figure 6.6.5
The interior quality at Barons Place Barriers to adoption of
off-site construction and their affect on the Barons Place
project
99 100
Figure 7.2.1 Figure 7.2.2
KPI results for Urban Splash and the Moho development KPI
results for Hyde Housing Association and the Barling Court and
Corbet House developments
104 105
Figure 7.2.3
KPI results for The Peabody Trust and the Murray Grove and
Barons Place developments
106
Figure 7.2.4
KPI Comparison of all developments with Construction Industry
data for 2006 Client Satisfaction (Product)
108
Figure 7.2.5
KPI Comparison of all developments with Construction Industry
data for 2006 Client Satisfaction (Service)
109
Figure 7.2.6
KPI Comparison of all developments with Construction Industry
data for 2006 Defects
111
Figure 7.3.1
Comparison of Construction Programme for all projects
112
Figure 7.4.1
Comparison of Construction Costs for all projects
115
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Abstract
ABSTRACT
Off-site manufacture has been used in the construction industry
for over 100 years, and as such, the benefits are both numerous and
widely known. However, take-up in the housing sector, in the form
of modular construction, has been much slower. Through detailed
case study research, this work seeks to understand why this is the
case, and whether these benefits can be transferred into the house
building process, to help meet the current demand for new
homes.
Three client organisations that have used modular construction
recently with apparent success have been investigated as part of
the research. By way of an initial postal questionnaire and follow
up semi structured interview, each organisations perception and
attitude towards modular construction, along with their principles
of best practice have been examined and analysed.
This has led to a number of interesting conclusions being drawn.
For example, modular construction will produce a better quality
finished product, as well as significant savings in terms of the
construction programme, when compared to traditional building
methods. Furthermore, the research has suggested that those clients
who procure using modular construction will be more satisfied as a
result,
The schemes reviewed have proved to be a great success in the
marketplace. This has led the author to feel that through careful
planning and systematic implementation, off-site manufacture
through modular construction is the future of house building.
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CHAPTER ONE
INTRODUCTION
If the industry is to achieve its full potential, substantial
changes in the culture and structure are required to enable the
improvements in the project process that will deliver our ambition
of a modern construction industry Sir John Egan
London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 1 Introduction
CHAPTER ONE
Introduction
1.1
Scope of Chapter
This opening chapter will set out the rationale, aim and
principal objectives of the dissertation. It will also outline
certain research questions that need to be
answered, and assumptions that have had to be made, in an
attempt to prove the aim and meet the objectives of the study.
Furthermore, a diagrammatic outline to the research methodology
will be presented and the structure of each subsequent chapter will
be briefly described.
By the end of the chapter, a clear understanding of the reason
for choosing the subject area, as well as the structure of the
study, will have been presented.
1.2
Rationale
Construction needs to increase its use of off-site methods
(Building, 2005a). That claim came seven years after the
publication of the Construction Task Forces Report, Rethinking
Construction (The Egan Report). This called for the industry to
industrialise and modernise in order to meet the changing needs and
objectives of its clients.
Why then, a considerable time since the Egan Report, and over a
decade since Sir Michael Lathams Constructing the Team, is the
industry still being urged to adopt more off-site manufacture? Both
knights recommended it as a way of increasing efficiency and, while
the situation cannot change overnight, why has takeup been so
limited?
Don Ward, deputy chief executive of Constructing Excellence in
the Built Environment, has offered a possible explanation. He feels
that the problem is
caused by a catch-22 situation, with the supply chain and
clients both being
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William Clayton (No. 2402164) Chapter 1 Introduction
reluctant to make the first move towards mass use of the method
(Building, 2005a). As a result, take-up is not happening widely
enough to lower unit costs.
This is clear with the large speculative house builders the
sector of the industry that offers the most practical source of
off-site manufacture, due to the standard range of products that
they construct. The biggest players have generally failed to
advocate these methods. In contrast, smaller, trendier developers
such as Manchester-based, Urban Splash, and forward thinking
Housing Associations, such as Hyde and The Peabody Trust have
adopted them and, consequently, reaped the benefits.
Urban Splash pioneered the UKs first private-sector,
multi-storey housing development to be based on prefabricated
volumetric modules. The 102-flat, Moho development, just west of
Manchester city centre, designed for young graduates and key
workers, has gained high recognition. Its volumetric manufacturer,
Yorkon, also won Building Magazines Off-site Specialist of the Year
2005 (Building, 2005b).
Meanwhile, in constructing Barling Court, in south-west London,
Hyde Housing Association has built a four-storey key-worker
apartment block, which is claimed to have taken 14 months less to
build than similar traditional developments (Spring, 2004a), and
reputedly worked out at 210,000 cheaper than a standard
prefabricated solution. In addition, the Peabody Trusts Murray
Grove, in east
London, was the first multi-storey housing project in the UK to
be entirely factory built.
Through detailed case study research, the dissertation will
analyse and evaluate the processes and procedures adopted by the
organisations claiming to maximise the benefits of off-site
manufacture. Examples will be drawn from the
private development sector, and the social housing market.
Ultimately, suggestions for best practice will be made. It is hoped
that these can then help to identify which off-site procedures
could be adopted by the larger house builders to assist in meeting
the Deputy Prime Ministers target of new housing over the coming
years, thus proving that off-site manufacture has a key role to
play in the future of house building.
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William Clayton (No. 2402164) Chapter 1 Introduction
1.3
Aim
To prove that off-site manufacture and modular construction is
significant in the construction industry and, consequently, the
future of house building in order to help meet current housing
demand.
1.4
Objectives
The study has four key objectives, namely:
1.
To identify the various techniques of off-site manufacture used
by each of the organisations.
2.
To highlight the benefits that those techniques bring to the
relevant projects and their clients.
3.
To identify the areas in which the large speculative house
builders should use off-site manufacture to improve their
efficiency and effectiveness, and meet government housing
targets.
4.
To show that modular construction has a significant place within
the construction industry in helping to meet housing demand.
1.5
Research Questions
In order to meet the aim and key objectives of the study, it is
necessary to answer a number of key research questions. These
are:
1.
What specific techniques of off-site manufacture do the
organisations use?
2.
What benefits do these techniques bring to the project, the
organisation and the construction industry as a whole?
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William Clayton (No. 2402164) Chapter 1 Introduction
3.
Are there any reasons why off-site manufacture may not be
adopted, and how can these be overcome?
4.
How does off-site manufacture compare in terms of construction
time and cost to traditional building methods?
5.
What improvements could be made to the off-site manufacture
procedure to make it more widely recognised and accepted?
6.
In which situations could the larger house builders adopt
off-site manufacture to help in meeting housing demand, whilst
improving their own efficiency and effectiveness?
7.
How relevant is off-site manufacture in terms of helping to meet
current housing demand?
8.
Is off-site manufacture the future of house building?
1.6
Assumptions
Certain assumptions have had to be made in order to undertake
the research if the aim is to be proved correct. These are:
1.
That the research can be carried out within the given
timeframe.
2.
That the representatives from each organisation will be
available to complete the questionnaire and be interviewed within
the timeframe of the research period.
3.
That the representatives from each organisation will be willing
to divulge potentially sensitive / confidential information on
their project, in order to make the research an accurate reflection
of off-site manufacture.
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London South Bank University Dept. of Property, Surveying and
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William Clayton (No. 2402164) Chapter 1 Introduction
4.
That the data / information received will be of sufficient
quality to formulate suitable conclusions to prove the aim /
objectives of the work.
1.7
Outline Methodology
The methodology for the research is shown in the flow chart
below:
Conception of idea
Development of idea
Literature Review
Assess questionnaire responses
Conduct questionnaire research
Devise research methodology
Conduct interview research
Assess interview transcripts
Analyse all data and formulate case studies
Conclusions and recommendations
Collate summary of key findings
Conduct benchmarking and KPIs
THE FUTURE IS MODULAR ?
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 1 Introduction
1.8
Dissertation Structure
Following this introduction, the dissertation will be split into
seven chapters and will be structured as follows.
Chapter 2 Off-site manufacture A History in Construction
The first literature review chapter will summarise the history
behind off-site manufacture. It will show how the uptake of the
techniques has evolved, from the aftermath of World War II and to
the end of the last millennium.
Chapter 3 Off-site manufacture Current Applications and
Implications for Future Use
The second literature review chapter will assess current
applications of offsite manufacture. It will examine the situation
since the turn of this century, and will also explore the
implications and applications for future use.
Chapter 4 Successful Projects Using Off-site Manufacture
The final literature review chapter will highlight those
organisations that are successfully using the techniques. It will
focus on the three organisations under review, namely Urban Splash,
Hyde Housing Association and The Peabody Trust.
Chapter 5 Research Design and Methodology
This chapter will outline the methodology for the research. It
will refer to the literature in justifying the rationale, as well
as detailing the questionnaire format and the principal themes of
the interviews.
Chapter 6 Data Analysis and Results Detailed Analysis
This first results chapter will be a detailed analysis of each
of the organisations and their projects, and will form the basis of
the case study approach.
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London South Bank University Dept. of Property, Surveying and
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William Clayton (No. 2402164) Chapter 1 Introduction
It will follow the format of the questionnaire, while comments
and interpretation to some of the responses from the interview will
be included where appropriate.
Chapter 7 Data Analysis and Results Benchmarking
The second analysis chapter will be centred on benchmarking and
key performance indicators. The results from each organisation will
be compared to each other, to the construction industry as a whole
and, in particular, to the new build housing sector. Overall
construction time and cost relevant to industry standards will also
be covered.
Chapter 8 Conclusions and Recommendations
The final chapter will detail a summary of key findings, and
draw conclusions by referring back to the objectives to assess what
the research has found. It will also highlight recommendations for
future application of the techniques, whilst identifying the
limitations to the research.
1.9
Chapter Appraisal
This first chapter has laid the foundation for the study by
outlining the rationale and stating the aim of the research.
Four key objectives have been identified as critical if the aim
is to be proved, while a number of research questions have been
posed, which when answered will help to meet these objectives.
Certain assumptions have had to be made in order to gain the data
and information required and these have also been explained.
Finally, an outline methodology to the research, and a brief
summary of each chapter has been detailed. It is now necessary to
investigate the existing literature on the topic of off-site
manufacture. This will be focus of the next three chapters,
commencing with Off-site Manufacture A History in Construction.
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CHAPTER TWO
OFF SITE MANUFACTURE A HISTORY IN CONSTRUCTION
Modular construction can produce existing, innovative buildings
that are cost effective and provide value for money throughout the
project lifestyle Alistair Gibb
London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 2 Off-site Manufacture A
History in Construction
CHAPTER TWO
Off-site Manufacture A History in Construction
2.1
Scope of Chapter
The literature review will be split into three chapters. The
scope of this first chapter is two-fold. Firstly, to identify what
is meant by the various terms concerning off-site manufacture.
Secondly, to summarise the history behind off-site manufacture in
the United Kingdom construction industry.
It will show how uptake of the techniques has evolved; from the
1800s, through its widespread use following the First and Second
World Wars, to the boom periods of the 1950s and 1960s, leading up
to the situation at the end of the last millennium. Specific
attention will be paid to the large high-rise residential buildings
that quickly became a feature of our towns and cities in the 1960s.
However, a devastating occurrence with one in particular had
long-lasting implications for future take-up.
Finally, the policy agenda will be examined, and reference made
to the Latham and Egan Reports. Recommendations in these documents
have shaped the applications and processes of off-site manufacture
that are commonplace today. As Egan, commented: substantial changes
in the culture and structure of UK construction are required to
enable the improvements in the project process that will deliver
our ambition of a modern construction industry (Egan, 1998).
Off-site
manufacture has and will continue to play a vital role in
achieving this ambition.
2.2
Definition of the Terms
Off-site manufacture, prefabrication and pre-assembly are part
of the spectrum of innovative contemporary techniques available to
those seeking greater cost effectiveness in construction (Gibb,
1999). Therefore, a natural starting point is to identify what is
meant by the terms off-site manufacture, pre-fabrication and
preassembly.
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 2 Off-site Manufacture A
History in Construction
A number of definitions are available in the literature.
In his 1965 book,
Prefabrication A history of its development in Great Britain,
White defined prefabrication as a useful but imprecise word to
signify a trend in building technology. He argued that if
prefabrication was related to every factory
manufactured product, the term could be stretched so wide as to
lose all meaning. Thankfully, in the subsequent 40 years, the word
has become commonplace and more precise. For the purposes of this
work the following definitions will be used.
Stirling (2003) defines off-site manufacture as any part of the
construction process that is carried out in controlled conditions
away from the actual site.
The Building Services Research and Information Association
(BSRIA) (1998) have proposed definitions for the other terms. They
define pre-fabrication as the manufacture of component parts of a
building and its services prior to their assembly on-site. The key
concept of pre-fabrication is that of adding value to
relatively
simple, low-intrinsic-volume materials and sub-components.
BSRIA (1998) goes on to identify pre-assembly as the manufacture
and assembly of a complex unit comprising several components prior
to the units installation on-site. The key concept here is that of
combining several high-intrinsicvalue components into a finished
entity, so that upon delivery to site only positioning and
connection to relevant supplies / services is necessary before the
product is put into use.
Many different terms are used to describe the process of
pre-assembly; therefore a number of sub-definitions are also
important to note. The following have all been developed by
Alistair Gibb (1999 and 2001); a widely recognised authority in the
field of research.
Non-volumetric pre-assembly The term non-volumetric is taken to
mean those items that do not enclose usable space, and being
assembled in a factory prior to being placed in their final
position. They may include several sub-assemblies and constitute a
significant part of the building or structure. Examples include
wall panels, structural sections and pipe work assemblies.
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 2 Off-site Manufacture A
History in Construction
Volumetric pre-assembly The volumetric category comprises units
that enclose usable space, but do not themselves constitute the
whole building. These units are also assembled in a factory, and
are substantially complete in themselves. This leaves only a small
amount of work to be completed on-site, and they are usually
installed within an independent structural frame. Examples include
toilet pods, plant room units, pre-assembled building services
risers and modular lift shafts.
Modular building This category comprises units that form a
complete building or part of a building, including the structure.
Again, they are substantially complete in themselves, which leaves
only a small amount of work to be completed on-site. They also may
be clad externally on-site, with cosmetic brickwork as a secondary
operation. Examples include out-of-town retail outlets, such as
McDonalds Drive-Thru restaurants, office blocks and motels, for
example Forte, and, most recently, residential apartments, both by
private and social housing developers (this will be discussed in
more detail in chapter 3). This type of off-site manufacture will
be the main focus of the research.
Figure 1 shows how off-site manufacture can be seen to encompass
the other terms, and how the various techniques interact.
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 2 Off-site Manufacture A
History in Construction
Figure 1 Off-site Manufacture and its related techniques
Off-site Manufacture
Pre-assembly
Pre-fabrication
Non-Volumetric
Volumetric
Modular Building
2.3
Origins of Off-site Manufacture in the United Kingdom
Off-site manufacture is not new to the industry. Gibb (1999)
cites examples of timber buildings using off-site manufacture as
early as the twelfth century. While a Building Research
Establishment (BRE) Report in 2003 highlighted its use in the 1770s
with the construction of the first Iron Bridge at Colebrookdale.
Other early examples include Londons Crystal Palace, built in 1851
for the Great Exhibition in Hyde Park and then relocated to
Sydenham in 1854, as well as the export of houses, churches and
hospitals to the colonies during 19th century.
Gibb (1999) feels that industrialised building techniques,
however, have not developed steadily and consistently, instead
evolving in a sporadic fashion and have even being totally
disregarded at times. White (1965) has been more critical. He wrote
that the examples of prefabrication before the 19th century were
isolated phenomena that had virtually no influence on the later
course of building evolution.
Before the First World War, housing standards were extremely
poor for much of the UKs population. Therefore, there was a great
need to replace the sub-
standard properties as well as to increase the number available
for rent (BRE, 2003).
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London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 2 Off-site Manufacture A
History in Construction
The impetus for developing mass prefabrication, however,
occurred after the Second World War. This was due to the necessity
for new housing, following the mass destruction of existing stock
that had occurred, and because such numbers could not be produced
by traditional methods.
Unfortunately, the ability of what was left of the house
building industry to respond to these demands was very limited, as
inevitably, there was a shortage of both traditional materials and
skilled personnel. These circumstances, therefore,
created the need to reconsider the procurement and construction
of buildings to service the demand.
2.4
1914 - 1939
Fortunately, the government recognised the problems of dealing
with postwar building at an early stage during the First World War.
This led to the formation of the Ministry of Reconstruction in
1917, whose brief was to consider and advise upon the problems
which may arise out of the present war and may have to be dealt
with on its termination (BRE, 2003). In time, the Ministry was to
conclude that it was in the field of steel and concrete housing
that prefabrication was most significant.
White (1965), however, summarised that prefabrication in the
inter-war period can be dismissed as a brief attempt to introduce
alternative buildings methods to the industry, after a lapse of
sixty years since the days of the export of cast-iron
buildings.
Prefabrication following the First World War had virtually
ceased by 1928. This was primarily because it had not managed to
consistently compete with traditional building. Its main
contribution had been to provide a small additional
number of houses, which would probably not have been built using
traditional methods due to material shortages. Essentially, this
period had been one that,
although helpful in terms of the number of houses built,
remained detached from the approach to building used by the rest of
the industry and, therefore, had no long-term impact on
construction at the time (BRE, 2003).
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Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 2 Off-site Manufacture A
History in Construction
2.5
1939 onwards
Following the destruction caused by the bombings of the Second
World War, there was again a shortage of housing stock and a need
for the deficit to be reduced quickly. In September 1942 then, an
Interdepartmental Committee on House
Construction was appointed. Presided over by Sir George Burt, it
became known as the Burt Committee.
Its brief was to consider materials and methods of construction
suitable for the building of houses and flats, having regard to
efficiency, economy and speed of erection. This included
considering the application of prefabrication.
The committees subsequent reports prepared the background for
further development of prefabrication, and led to an increase in
the number of non-traditional properties being built in the UK.
This included timber frame houses, which were imported in
significant numbers.
These post-war years were marked by massive government
intervention and by the granting of subsidies and, in October 1944,
The Housing (Temporary Accommodation) Act was passed. It authorised
the government to spend up to
150,000,000 on the provision of temporary housing (BRE, 2003)
and between 194548, around 157,000 temporary houses were
manufactured, or imported, and erected. However, this was
significantly less than the numbers expected, and the gap between
expectations and actual provision has contributed to the perception
of a poor performance.
Richard Sheppard, in his 1946 book Prefabrication in Building,
was an advocate of the techniques. However, instead of questioning
its feasibility believing it had been amply demonstrated that
efficient buildings could be constructed from mass-produced factory
units he summarised achievements in the prefabrication of buildings
in England and America.
Sheppard agreed that large measures of prefabrication were
required in order to meet both the housing demand and the demand
for new schools. However, he
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noted that there was a tendency to assume that prefabrication
developed merely to supplement orthodox methods of construction
during a period of emergency.
In summary of this period, White (1965) identified that it has
been characterised by changes in materials and techniques, which
had implications far beyond the field of housing.
A characteristic of the 1950s was the major push to provide
increasing numbers of housing units within a very short space of
time, while making maximum use of restricted site space. These
constraints and cost limits led to the introduction of Large Panel
Systems (LPS) Construction, using existing technology first
developed in Denmark in 1948 (BRE, 2003).
2.6
Large-panel high-rise residential buildings
In the early 1960s, the first of many tower blocks began to be
built in areas of London, such as West Ham an area badly affected
by the bombs of the Second World War, and with several approaching
slum status. The design chosen for many of these was the Larsen
Neilson method: one where pre-cast reinforced blocks are slotted
into place on site, then bolted and cemented together. This was
seen as a safe and quick way to provide new homes.
In 1965, the London Borough of Newham commissioned nine,
twenty-two storey blocks. As the end of the decade approached, many
of these tower blocks had been constructed, giving local people a
chance to move out of old, usually unfit properties, into smart new
homes in the sky. The various social problems created by the tower
block lifestyle had not yet come to light and many people were
fairly content to move into a new high-rise flat in order to escape
damp, dirty and rundown houses.
However, one event had both devastating occurrences and
long-lasting implications for the future perception of
prefabrication.
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2.6.1
Ronan Point, Newham, East London
Construction of the Ronan Point block started in July 1966,
being handed over to the council in March 1968. It was 80ft by 60ft
in area and 210ft high, and consisted of 44 two-bedroom flats and
66 one-bedroom flats.
At 5.45am, on 16 May 1968, an explosion occurred in Flat 90,
four floors from the top of the building. This momentarily lifted
those top floors, while the now
unrestrained flank wall was blown out. When the load from those
floors returned, the supporting walls were no longer present to
offer any resistance and hence the weight of some of the upper
construction descended through a storey height before impacting on
the next lower floor of the south-east corner. The modern design of
the building had proved to have a major fault, which allowed the
domino style collapse of the wall and floor sections.
Only eight flats remained vacant at the time of the explosion
and it was fortunate that four of these were situated in the
south-east corner which collapsed (BRE, 2003). However, there were
still five fatalities (four directly as a result of the explosion
and collapse).
The cause was later found to be a build-up of gas from a leaky
cooker connection that was ignited by a lady hoping to make an
early morning cup of tea, contrary to the initial local rumours
that it was caused by an IRA bomb maker gone wrong.
The incident led to a ban on the supply and use of gas in
high-rise premises, although this has now been revised, partly due
to the difficulties in upgrading and renewing heating methods in
the blocks themselves. However, the implications in terms of the
publics perception of prefabrication have had long-lasting
implications.
2.6.2
Other problems with high-rise LPS systems
Following the collapse of Ronan Point, the then Minister of
Housing and Local Government instructed local authorities, in
August 1968, to appraise the structural design of the existing and
proposed LPS blocks. The BRE noted that this
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programme was intended to reduce the probability of progressive
collapse in the event of the loss of load-bearing elements (BRE,
2003). The result was a nationwide programme of assessment and the
strengthening of many existing LPS blocks.
However, there have also been other problems with these
large-panel highrise buildings. For example, the BRE (2003) has
noted that many of the systems have also suffered from water
penetration and poor thermal performance. Frequent condensation has
also led to concern and dissatisfaction among tenants. However,
many of the problems with these systems are a result of poor
workmanship rather than design, leading to prefabrication being
associated with poor quality buildings. Although the specific
problems at Ronan Point were not all related to the form of
construction, the publicity has been closely associated with the
method of building, which has again contributed to a negative view
in some quarters.
Even though the techniques have increased over time, both in
terms of scope and number, there has still been prevailing stigma
attached to off-site manufacture. Therefore, in order for off-site
manufacture to prosper, these problems must be recognised and
overcome. This will be discussed in more depth in chapter 3.
However, White (1965) noted that where prefabrication has been
successful, there has been a unity of purpose and close
collaboration between client, designer, manufacturer and
contractor. He felt that many failures since the war can be put
down to a lack of effective co-operation and timing whereby the
correct solution presented by and to the right people at the right
time has often been the basis of the success achieved.
Since those dark times for off-site manufacture, the situation
has changed. This has been a result of both advances in innovation
and a general improvement in the efficiency of construction firms.
As such, the benefits of off-site manufacture are now widely
recognised. These have been published by research organisations,
such as the Construction Industry Research and Information
Association (CIRIA) and the BRE.
The benefits of off-site manufacture are the subject of chapter
3. However, they will be briefly mentioned here. A CIRIA report in
1999, entitled Adding Value to Construction Projects through
Standardisation and Pre-assembly, focussed on the
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value to be gained from the application of off-site manufacture.
The report concluded that the deliberate and systematic use of
pre-assembly, started early in the process, will add value to
projects by increasing predictability and efficiency (Gibb,
2001).
2.7
Non-Domestic Applications
Non-domestic applications are generally considered outside the
scope of this work. However, it will briefly be touched upon here
to ensure the continuity of the historical context, and because the
use of prefabrication is well established, while the scope for
future application is considerable. This is because the size,
shape, form and fabric of non-domestic buildings are more diverse
than those found in UK housing (BRE, 2003).
Many commercial clients perceive the construction time of new
outlets as a delay in their ability to trade and, as such, apply
pressure for faster build times. Fast track construction schemes
have been tried for a number of years to reduce time spent
developing new outlets, and prefabrication has been identified by
many as one of the ways of achieving faster completion. For
example, McDonalds Restaurants use prefabrication to build their
new outlets, recently setting their record of a completed outlet
being built and open for business, in Runcorn, Cheshire, within 13
hours of starting construction on prepared ground (BRE, 2003). They
have also built the largest fast-food restaurant in Europe a
2,200m2 unit near Greenwichs Dome in just 15 weeks using modular
construction (Robert Gordon University, 2002). These fast, economic
developments have considerable commercial implications for the
businesses. A range of clients from hotels (such as Travelodge in
the form of
prefabricated bathroom pods) to retail outlets are now using
some form of prefabricated procurement.
2.8
Policy Agenda
2.8.1
The Latham Report
In 1994, the UKs Joint Review Body published Constructing the
Team by Sir Michael Latham. The report, more commonly known as The
Latham Report, was jointly commissioned by government and the
industry, with the participation of many
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major clients. It was set up to consider procurement,
contractual arrangements and the current roles, responsibilities
and performance of the participants, including the client (Latham,
1994). The report was produced by a single individual, not a
working party or committee, and in the authors own words was a
personal report of an independent, but friendly, observer.
In essence, the review attempted to put forward solutions to
problems that it had identified were preventing clients from
obtaining the high quality projects they required. The report
concluded that an enhanced performance could only be
achieved by team work in an atmosphere of fairness to all of the
participants a process of finding win-win solutions (Masterman,
2002).
Altogether the Latham Report made thirty recommendations. One
specifically important in this context was for a 30% reduction in
construction cost. Much of the debate about meeting this target has
centred on greater use of industrialised building methods, such as
off-site manufacture. Since the publication of the report, Evans
(1995) has noted today the pressures on the industry and the
capabilities of more flexible manufacturing technology are
different from the 1960s. There is a growing sense that now is the
time for another push towards economies of scope and towards
prefabrication.
The recommendations were initially accepted in principle by all
those involved; however, putting them into practice has been slower
than envisaged. Furthermore, work on their implementation has been
somewhat overtaken by the recommendations of Rethinking
Construction.
2.8.2
The Egan Report
The Egan Report Rethinking Construction was published in 1998 by
the Construction Task Force. It was commissioned by the Department
of the
Environment, Transport and the Regions (DETR) as a result of the
growing dissatisfaction of both public and private clients with the
performance of the industry. The task force was charged with
investigating and identifying methods of improving the efficiency
of the industry and the quality of its products.
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The report was very critical of the industry for its past poor
performance and called for radical change in the way projects were
implemented. It concluded that the industry needed to concentrate
on becoming more efficient, improving the quality of its output and
improving the satisfaction of its clients (Egan, 1998). One of
its
recommendations was to move towards sustainable construction,
with the emphasis on prefabrication and off-site assembly.
There has been some criticism of the report in certain quarters.
This has centred on its provocative and unnecessarily hostile
approach and its failure to address the needs of occasional /
one-off clients and the implementers of small to medium sized
projects that make up a large proportion of the industrys annual
workload (Masterman, 2002).
However, the report highlighted how the construction industry
should follow the example set by manufacturing as a way of
improving effectiveness and efficiency. In particular, the housing
sector can be viewed as the frontline for off-site manufacture. The
report showed how Housing Associations, such as The Peabody Trust,
The Guiness Trust and Southern Housing Group have implemented the
lessons learnt from abroad to improve the procurement of low-cost,
high-quality adaptable housing. In fact, it went so far as singling
out the social housing sector as exemplary, stating: the Task Force
believes that the main opportunities for improvements in house
building performance exist in the social housing sector. However,
we would expect improved practice in social housing to affect
activity in the wider housing market (Egan, 1998). Yet, history has
proved that the wider housing market and, in particular, the larger
speculative house builders are sceptical and slow to copy the
success of their not-for-profit counterparts.
The report has also led to a range of initiatives that have had
a major impact on the industry, such as the Movement for Innovation
(M4I) and the Construction Best Practice Programme. Prefabrication
has been identified as a major way forward in delivering these
required improvements.
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2.9
Chapter Appraisal
This chapter has set the background for off-site manufacture,
prefabrication and pre-assembly in the UK construction industry. It
has defined the various terms since an understanding of these is
critical to the overall understanding of their application in the
industry and has given a brief historical summary, by looking at
the origins of off-site manufacture, from sporadic beginnings
pre-19th century to more widespread adoption following the two
World Wars. This was in an attempt to deal with the chronic
shortage of housing stock that resulted from the devastating
bombings. It showed how the techniques supplemented the more
traditional
methods, rather than providing the answer to all the industrys
problems.
From there, it has been shown how government intervention in the
1940s and uptake of methods increased in the 1950s and 1960s.
However, a notable
occurrence the Ronan Point block collapse has resulted in the
techniques suffering from a poor perception among the wider
population.
Finally, recent government-sponsored policy agenda has been
investigated. This has taken the form of the Latham and Egan
Reports reports that were intended to change the way the
construction industry operates by encouraging firms to become more
like the manufacturing industry through greater adoption of
increasingly industrialised building techniques.
It is now necessary to assess whether the recommendations made
by Sir Michael and Sir John have had an effect on the uptake of
off-site manufacture in the industry. This will be the focus of
chapter 3, along with an evaluation of the benefits and potential
barriers to adoption. Finally, it will summarise the applications
of offsite manufacture since the turn of the new century up to the
present day.
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CHAPTER THREE
OFF-SITE MANUFACTURE CURRENT APPLICATIONS AND IMPLICATIONS FOR
FUTURE USE
Prefabrication is much more than a trendy concept, it offers the
possibility of remoulding construction as a manufacturing industry.
It represents one of the positive ways forward for underpinning the
major changes that have been identified as necessary for improving
construction Building Research Establishment
London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 3 Off-site Manufacture
Current Applications and Implications for Future Use
CHAPTER THREE
Off-site Manufacture Current Applications and Implications for
Future Use
3.1
Scope of Chapter
This chapter will assess whether the recommendations made in the
Latham and Egan Reports have had an affect on the industry by
detailing the current applications of off-site manufacture, from
the start of the millennium up to the present day. It will show how
the industry is now applying the techniques in various forms.
The benefits of off-site manufacture are both widely recognised
and publicised, and will be discussed to improve the overall
understanding of the current situation. Some of these benefits will
impact directly on project performance and cost, while others have
more indirect advantages to both the client and project team.
However, there are still various barriers to adoption. A number
of these have resulted from the perceived poor performance of the
techniques during difficult periods in the 1960s. These will be
detailed, and it will be shown how they can be overcome, and how
successful projects using off-site manufacture can be developed as
a result.
Finally, the chapter will explore the applications and
implications for future use, as off-site manufacture is much more
than a trendy concept. Instead, it could offer the possibility of
remoulding construction as a manufacturing industry. These methods
are being used in an attempt to meet the housing targets set by the
Deputy Prime Minister.
3.2
The Current Situation
The UK construction industry is currently using prefabrication
in a wide variety of forms and applications. This ranges from the
simple prefabricated site hut, to volumetric units that can be
delivered to site and integrated into the structure of a
building.
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The BRE (2003) has identified modularisation or modular design
as key to prefabrication. Modular design refers to construction
using standardised units or
standardised dimensions. Modular buildings do not have to be
built by prefabricated techniques, however they are usually
involved. A variety of successful modular
developments have recently been procured in the UK and these
will be described in chapter four.
Off-site manufacture is not just limited to the building fabric,
but can also be applied to the plant and services within a
development. BSRIA recently completed a DETR study into the
application of prefabrication of services (Wilson, Smith and Deal,
1998). This included a comparison with the traditional approaches
and
identification of some of the issues that determine whether the
approach is successful. The prefabrication of building services is
generally considered outside the scope of this work. context of
current uses. However, it is mentioned here to provide an
up-to-date
An important point to note is that the implementation of
off-site manufacture in the UK has been sporadic. It is often
dominated by the larger construction
companies, which have shown most interest in using
prefabrication techniques to improve productivity and move towards
leaner construction (BRE, 2003). The
concept of lean construction was one of the main recommendations
by Sir John Egan. However, uptake of off-site manufacture by the
house building industry, and in particular the larger developers,
has been much slower. Instead, it has been the smaller developers,
and notably the Housing Associations, who have used the techniques
to great effect. Perhaps an explanation for this is because they
are more concerned with client satisfaction and quality of product
than profit margins and share prices. In reality, the larger
speculative house builders need more convincing of the benefits, as
they have more to lose if things go wrong, in respect of the
relationship that they have with their shareholders.
In April 2000, the DETR produced a Housing Green Paper entitled
Quality and Choice: A Decent Home for All. This identified
prefabrication as a means of providing affordable housing, and
considered the ways in which more resources could be used.
Specifically, the paper stated: we expect to see progressive
take-up
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of the technique over the next few years, for both social and
private house building, as the benefits are more clearly
demonstrated (DETR, 2001a).
3.3
Benefits of Off-site Manufacture
Off-site manufacture has many benefits to the industry as a
whole, as well as at project level. Much of this benefit and added
value is indirect. Davis Langdon (2004) note that, while the cost
issue remains unresolved, the supporters of off-site manufacture
argue a broader case based on social and environmental issues.
For example, using prefabrication allows the time spent working
on site to be reduced. This means that the impact of the site on
the local environment is for a shorter period of time. Furthermore,
site work is traditionally vulnerable to disruptions from extremes
of weather. By using prefabrication, the site will be vulnerable
for a shorter time, and hence, the risk of delay and the
requirements for protection will be reduced. Fast track
construction systems often use prefabricated components to rapidly
erect a weather tight shell for the building. This enables the
internal fit-out to be moved forward in the process and continue
despite the external weather conditions.
Many of the benefits of prefabrication will be gained when it is
considered early in the design process, and ideally at the concept
design stage (Reid, 1999). Alternatively, problems of a lack of
compatibility, and a resulting increased cost, can occur where the
techniques are not considered until later in the process. In fact,
prefabrication requires all involved in the process to go through a
learning curve to optimise the benefits of using the system.
All these factors have benefits to the programme. As Davis
Langdon (2004) point out, there are opportunities to compress
project durations and reduce risk by transferring work off site and
by simplifying site operations and on-site snagging. However, the
downside of this programme compression is that more work needs to
be completed pre-contract, and hence earlier design freeze dates
are required.
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Prefabrication can also offer opportunities for dealing with the
problems of the declining workmanship standards and skilled labour
shortages on site. This was something that was highlighted as a way
of meeting Egans targets. In a factory environment, the quality of
the finished product is much easier to assure than on site. All
that remains is to ensure that the on-site assembly meets the
required standards to allow the design to perform to its
requirements. However, the BRE note that careful attention is
needed with this, as it has been a stumbling block in the past
application of prefabricated systems (BRE, 2003). In fact, concern
has been voiced that the very move to prefabrication will further
reduce the skills base in the industry. In 2001, Ian Davis, the
Director General of the Federation of Master Builders said:
increased prefabrication is seen as one answer to problems that
beset the industry, including the skills shortage, inconsistent
quality and low margins. Whilst
prefabrication has a role in improving the industry it must not
be pursued at the expense of the skills shortage training needed
for traditional forms of construction.
Careful quality control of manufacturing processes enables waste
to be controlled and minimised through appropriate design and
recycling opportunities. In addition, the use of prefabricated
components should cut the volume of site spoilage associated with
current practices of over-ordering and poor site handling for the
equivalent traditional processes.
Benefits of quality are derived from standardised processes
under factory conditions. Davis Langdon (2004) point out that one
of the benefits of the factory process is that improvements
developed on one project can progressively improve the basic
product. This has further benefits in respect of safety and
working
conditions, in that safety improves by transferring work into a
controlled environment.
Davis Langdon (2004) identify another benefit in the whole life
costing. Enhanced specification standards and build quality can
also reduce occupancy costs related to energy use, defects and
repairs. However, these benefits of good whole life performance can
be offset by high costs of adaptation. On large projects, economies
of scale can be achieved through off-site manufacture with orders
of 500 units attracting a discount of 5 10% (Davis Langdon &
Everest, 2002). These savings will be partially offset by transport
costs
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and on smaller projects additional design and set-up costs.
However, there are also further indirect savings through reduced
site supervision, simplified inspections, fewer variations and less
re-working.
3.4
Barriers to Application
Robert Gordon University conducted a government sponsored
research report in 2002 entitled Overcoming Client and Market
Resistance to Prefabrication and Standardisation in Housing. It
examined potential barriers to the use of
prefabrication and the ways in which these may be overcome. Six
key areas were highlighted.
3.4.1
General Image
The image of prefabrication has been clouded by the experience
of past applications and, in particular, the 1960s high rise
housing schemes. However,
many of these problems have resulted from poor workmanship
rather than design deficiencies (Robert Gordon University, 2002).
The effect has been that these
experiences present a barrier to some parts of the industry
accepting prefabrication as a viable method of building
procurement.
This is now being countered through one-off demonstration
systems, where close supervision of site activity ensures that the
end result is a product with workmanship quality equivalent to that
of traditional systems (BRE, 2003). Thus, the quality of assembly
is important in ensuring the long-term success of prefabricated
systems. An indication of fitness for purpose for the Murray Grove
development is the fact that no alterations to the form or fabric
of the building has been carried out in the six years since
completion (Spring, 2006).
3.4.2
Perceived Performance
Many of the prefabricated buildings that were constructed
between 1946 and the mid-1970s have been viewed as having a shorter
lifespan than that of equivalent traditional buildings. The Robert
Gordon University (2002) study noted that the
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perception that prefabrication offers a non-permanent solution
is one of the potential barriers that exist for its wider
acceptance as a mainstream procurement option.
Building Magazine recently instigated a return visit to the
modular Murray Grove development in North London seven years after
its construction to assess whether the reality has lived up to
expectations. The result was positive, with good performance being
achieved in the critical areas of functionality and build quality,
and moreover, the building has low maintenance costs. Although not
without its teething problems, such as noise penetration, Murray
Grove has shown that barriers such as the perceived performance can
be overcome.
3.4.3
Customer Expectation
One barrier to adoption in housing, in particular, is the
perception that the public want a traditional brick finished house.
However, the masonry industry is developing new factory
prefabricated systems that can be delivered to site, and which
maintain the traditional masonry appearance (Robert Gordon
University, 2002).
Positive feedback has again been received from the Murray Grove
site. It indicated that tenants are attracted by the modern
external appearance of the building, which suggests a possible move
away from traditionally finished houses in some quarters of the
housing industry.
3.4.4
Perceived Value
It has suggested by Craig, Laing and Edge (2000) that resistance
to off-site manufacture, particularly in the housing sector, is
partly caused by the perception that property is an investment. As
such, off-site manufacture is not necessarily seen to be a good
investment, based on historical experience.
Evidence from Murray Grove has suggested that the build cost was
5% more than traditional construction costs, according to the BRE.
The construction cost was 1,015/m2, with the average cost per flat
of 77,800 (Spring, 2006). However,
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maintenance costs at Murray Grove are also considerably lower
than the Building Cost Information Service comparison - 7,000 per
annum for external and internal maintenance compared to 34,400
(Spring, 2006).
3.4.5
Industry Culture
One factor the Robert Gordon University (2002) report found that
is restraining the use of some prefabrication in housing is the
availability of plant for handling the larger systems on site. They
found that a change in site culture, and industry use of plant,
would encourage the use of panel prefabrication systems.
Furthermore, the attitude of the construction industry has
suggested that it is reluctant to try new methods and believes that
off-site manufacture will cost more than traditional methods of
construction. Despite evidence to the contrary, this
attitude, still found in some parts of the industry, is
difficult to counter.
3.4.6
Product Awareness
The procurement of prefabricated components for a project is
often a matter of designers being aware of the availability of a
given system. The BRE (2003) note that designers are unlikely to
use a system for which they do not appreciate the benefits for the
construction, or for which they do not understand how the system
impacts on the design process. Manufacturers are producing
innovative
prefabricated products; however they consider that it is the
designers that are conservative and reluctant to try out new
systems (Reid, 1999).
Davis Langdon (2004) highlight two further potential barriers to
adoption as being the need for project specific research and issues
with planning. There are more than 40 different suppliers of
panellised and volumetric systems in the UK, with no standard means
of comparison or historic cost data (Davis Langdon, 2004). Greater
availability of information concerning the competitive position of
alternative technologies would enable clients to proceed without
having to undertake their own comparative studies. Furthermore,
decisions by planners can act as a constraint by
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influencing the layout and appearance of buildings, or by
extending the preconstruction period.
The barriers mentioned above are often based on a perception of
difficulties that have arisen from past experience, rather than
from actual technical constraints. However, none of these barriers
should exist if the industry is educated of the merits of using
prefabrication (BRE, 2003). Furthermore, it is important to note
that some aspects of prefabrication used in construction have
managed to avoid many of these problems and are now well
established systems.
The real test for prefabrication is to move from the successful
one-off demonstration projects to mainstream developments. Both
private and social
housing markets will provide the keys for this success. A number
of successful projects that have used off-site manufacture are
examined in chapter four.
3.5
Applications for Future Use
Off-site manufacture is currently used to some degree in all
aspects of construction. However, the extent of this future
application can be affected by the barriers previously mentioned.
In fact, the most important challenge for the future of off-site
manufacture is to overcome these barriers and, in particular, to
ensure that the mistakes of the past are not repeated (BRE, 2003).
Failure to do this will result in off-site manufacture not meeting
its massive future potential.
Off-site manufacture is much more than a trendy concept, it
offers the possibility of remoulding construction as a
manufacturing industry. It represents one of the positive ways
forward for underpinning the major changes that have been
identified as necessary for improving construction (BRE, 2003).
Off-site manufacture has the capacity to drive down costs and
improve productivity. However, claims for the level of improvement
that could be achieved need to be scrutinised and evidence is
required to support them. With regard to the other benefits, all
the issues need to be understood and properly demonstrated
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before the more conservative parts of the industry respond.
This, in turn, should lead to a greater uptake of the systems.
The potential environmental benefits of off-site manufacture are
numerous. However, real assessments are required of the different
applications to show whether these benefits are marginal, or more
significant, when compared to traditional methods. Furthermore,
environmental legislative pressures on construction activity are
likely to continue to grow in the future. If the environmental
benefits can be demonstrated for some of the techniques, then they
should flourish in the future.
A BRE report in 2003 noted that off-site manufacture could allow
greater client choice and involvement, particularly in housing,
where a variety of different systems can be realised from
manufacturers. However, Alistair Gibb has noted their application
and drivers, pragmatism and perception need to be considered in the
light of current technology and management practice (Gibb,
2001).
The future application of off-site manufacture in the UK will be
determined by the economic and environmental benefits for the
particular applications. In order to ensure that these are
successful, the performance of the systems needs to be established
over the whole life of the structure. Furthermore, without
market
acceptance of the end product, off-site manufacture will not
flourish. Therefore, it is important to ensure that the aesthetics
of the system meet market demand. This is a design, rather than
technological, challenge.
3.6
Chapter Appraisal
This chapter has assessed whether the recommendations made by
Sir Michael Latham and Sir John Egan have had the desired effect on
the industry. It has detailed the current applications of off-site
manufacture, from the turn of this century to the present day.
Consequently, the industry is now applying the
techniques in a variety of forms and applications.
The benefits of off-site manufacture are widely recognised, and
these have been highlighted as a way of improving the overall
understanding of the current
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William Clayton (No. 2402164) Chapter 3 Off-site Manufacture
Current Applications and Implications for Future Use
situation. These beneficial effects have been described in terms
of factors such as performance and cost, while more indirect
advantages to all parties that advocate the techniques have also
been mentioned.
However, there are still various barriers to adoption. In a
number of cases, these have resulted from the perceived poor
performance of the techniques during past decades. Although, it has
been shown how these difficulties can be overcome.
The chapter has also explored the applications and implications
for future use in delivering quality housing in an attempt to meet
the governments targets. Off-site manufacture offers the
possibility of remoulding construction as a manufacturing industry
this was one of the issues that laid the foundation of the Egan
Report.
It is now necessary to examine those organisations that are
successfully using the techniques. Examples will be drawn from both
the private and social
housing sectors. Through detailed examination, it will be shown
where the benefits lie and where the larger house builders should
take heed.
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CHAPTER FOUR
SUCCESSFUL PROJECTS USING OFF-SITE MANUFACTURE
Murray Grove has been hailed by the Government and others as a
breakthrough for innovative housebuilding. We hope it will prove a
catalyst for innovation in the industry as a whole Dickon Robinson,
Director of Development, Peabody Trust
London South Bank University Dept. of Property, Surveying and
Construction MSc Dissertation
William Clayton (No. 2402164) Chapter 4 Successful Projects
Using Off-site Manufacture
CHAPTER FOUR
Successful Projects Using Off-site Manufacture
4.1
Scope of Chapter This chapter will examine those organisations
that are successfully using off-
site manufacture. Reference will be made to Urban Splashs Moho
development in Manchester; Hyde Housing Associations Barling Court
and Corbet House sites in London; and Murray Grove and Barons
Place, developments by The Peabody Trust, also in London, which all
deploy off-site manufacture to great effect. They have featured
heavily in trade magazines, the national press and an architectural
exhibition, as pioneering developments in the pursuit of greater
use of modern methods of construction. design and construction.
They have won numerous awards for their innovative
Through detailed examination of such successful projects, it
will be shown where the benefits lie to the industry, and where the
larger house builders can learn from their smaller
counterparts.
4.2
Successful Projects using Off-site Manufacture
Following the Egan Report, developers such as Urban Splash and
Housing Associations such as Hyde and The Peabody Trust have
implemented off-site manufacture to great effect. These volumetric
and modular developments, for both the private and key-worker
sectors, have recently received much recognition and credit in
sources such as Building.
Each of these successful developments will now be examined in
more detail to improve the understanding of the benefits to the
house building industry as a whole.
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4.2.1
Moho Urban Splash
Moho is a pioneering development of 102 flats in Manchester by
developers Urban Splash and architects ShedKM. Arguably, it has
made prefabricated housing fashionable.
Figure 4.1 Urban Splashs Moho Development
(Source: courtesy of Urban Splash)
The seven storey development of fully furnished units is the UKs
first privatesector multi-storey housing development to be based on
prefabricated volumetric units. While other house builders were
hesitating with off-site manufacture, Urban Splash went the whole
hog. This was as a result of a greater demand for smaller, compact
units to suit young graduates or key workers and to do so within a
tight timeframe, to a high quality and without defects (Spring,
2005).
What makes Moho unique is that the modules are realigned
end-to-end to give maximum window space, and it is the first scheme
with each flat contained within a single module. However, as Spring
(2005) points out, there is no
claustrophobic feeling. In fact, he notes there is a liberating
sense of space and daylight, with the living room looking onto a
communal courtyard through floor-to-
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ceiling glazing.
The flats also benefit from clip-on balconies, which shade
the
windows from the high summer sunshine. With an internal area of
just 38m2 the flats are small. However, innovative thinking by
ShedKM, using principles derived from yacht design, ensures that
all available space is used efficiently. For example, storage areas
are hidden behind sliding doors in odd corners off the bedroom.
Even the furniture is yacht-inspired and has been supplied by
furniture shop Mooch.
The flats are arranged in three seven storey wings, around a
central courtyard serving as a communal garden for residents, and
doubling-up as the roof of a car parking podium one floor above
street level. The ground floor on all sides is
occupied by shops and cafs that open onto the pavement.
Unlike other schemes, there has been no attempt to disguise
Mohos modular construction, with its faades being made up of
rectilinear grids of panels, which the architects call a modular
Cubist look (Spring, 2005).
Overall, Moho should be popular with young people setting up
home. The starting price of 131,000 might prove to be a sticking
point, however, being a little above the starter homes average;
although, as Spring (2005) notes, that seems a small price to pay
for contemporary, urban chic, and modular housing has at last found
a place within the aspirational world of young urban
professionals.
In recognition, Moho has won a number of prestigious awards,
including Building Magazines Off-site Specialist of the Year 2005
for its manufacturer Yorkon; and Best Major New Housing
Development; as well as Best Innovative Technology at the National
Homebuilder Design Awards.
4.2.2
Barling Court Hyde Housing Association
Hyde Housing Association teamed up with PCKO Architects in
procuring the Barling Court development in south-west London. On
face value, it appears no
different from other prefabricated developments; however, what
makes Barling Court different is the location of its prefabrication
plant Krakow, southern Poland.
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William Clayton (No. 2402164) Chapter 4 Successful Projects
Using Off-site Manufacture
Figure 4.2 Hyde Housing Associations Barling Court
Development
(Source: Author)
In Poland, technical competence is combined with labour costs
that are just one-sixth of UK rates. The result is that Barling
Courts all-in construction costs, including full fitting out,
amounts to 700,000, or 1,260m2. Hyde claims that it is at least 12%
lower than a traditional new-build and 20-30% less than equivalent
modular systems (Spring, 2004a). Furthermore, the flats were
erected in just four days on prepared concrete strip foundations.
The whole scheme was fully finished with services working and site
landscaped in less than four months.
The BUMA System named after the factory where the prefabricated
units are assembled has a number of benefits. Firstly, it provides
a quality that can only be achieved under factory conditions. Not
only are the modules completely clad and roofed in the factory, but
are also fully fitted-out with kitchens, bathrooms, plaster, paint
and flooring. Even the communal entrance and staircase leading to
each flat was prefabricated as four modules, one for each
floor.
Another benefit is that the modules can be quickly and
repeatedly unbolted, transported to a new site and reassembled. In
fact, a prototype system was de-
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William Clayton (No. 2402164) Chapter 4 Successful Projects
Using Off-site Manufacture
assembled and re-erected eight times as a travelling exhibition
(Spring, 2004a). The system also has a good EcoHomes rating
exceeding sound insulation and energy efficiency standards. Added
to this are the benefits gained through cost and speed of
construction.
The main challenge for the BUMA system is how can it shake off
the stigma of the mean, poky, repetitive, flimsy prefabs that has
persisted over the last halfcentury? BUMAs answer lies in the
structure of the apartments, which are designed for a 60-year life,
no matter how many times they are dismantled and re-erected
(Spring, 2004a). The flats are made up of two modules, measuring
50m2 for a one-bedroom flat and 65m2 for a two-bedroom flat. Spring
(2004a) notes that with their sense of space, high-quality
fittings, smooth plaster finishes and solid floors, there is
nothing about the interiors that suggests prefabrication. However,
their prefabricated origin is more evident from the external
appearance, and it is something that architects PCKO has not shied
away from. High quality aluminium panels and render have been used,
and sliding sun-screens of slatted timber have been added to soften
the buildings slightly repetitive, commercial appearance.
The Barling Court site has also featured in the recent
Prefabulous London The A to Z of Modern City Homes Exhibition
produced by the Building Centre Trust. This showcased innovative
and pioneering prefabricated developments across London. It has
also recently been commended in the Best Innovative Technology
category at the National Homebuilder Design Awards 2005.
4.2.3
Corbet House Hyde Housing Association
This development is the second collaboration between Hyde
Housing Association and PCKO Architects using the BUMA System. The
scheme consists of 18 flats 9 one-bedroom and 9 two-bedroom.
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William Clayton (No. 2402164) Chapter 4 Successful Projects
Using Off-site Manufacture
Figure 4.3 Hyde Housing Associations Corbet House
Development
(Source: Author)
Cost and speed of construction are again key factors in the
procurement process. The Polish workforce assembled six of the
flats in just three days. The remaining flats which are delivered
complete with carpets and Ikea kitchens including appliances were
put together in two phases during the summer of 2005.
Hyde Housing Association claims that the cost of the scheme is
10% less than traditionally constructed housing, due to the cheap
Polish labour. Polish
workers are paid less than half of the UK minimum wage (Weaver,
2005). A further benefit of the BUMA system is its flexibility.
This will allow Hyde to relocate them when the short-term lease on
the Corbet House site expires.
Hyde is planning to provide around 150 BUMA homes in Britain
over the next five years, and to supply a further 150 for other
house builders and housing associations (Weaver, 2005).
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Like its Hyde counterpart Barling Court, Corbet House also
featured in the Prefabulous London Exhibition.
4.2.4
Murray Grove The Peabody Trust
The Peabody Trust one of the largest and oldest housing
associations in London has always been keen to develop new
construction technologies and to set new standards in
cost-effective quality house building.
In March 1998, Peabody received planning permission for 30
factory-built, modular homes on a difficult brownfield infill site
in Hackney. They wanted the
project to reflect the innovation of modular technology, reduced
construction times and minimised disruption on site. The resulting
development was the first multi-storey housing scheme to be built
in a factory.
In an attempt to achieve a fixed-price contract, the Trust
developed this scheme as a prototype in prefabricated housing using
modular construction. Spring (1999) points out that building costs
were 20% higher than conventional building costs. However, he
expected these to be largely recouped in the extra six months
rental revenue earned by halving the construction time. The
accommodation was targeted at young single people, couples and flat
sharers who prefer low rental housing to the greater commitment of
a mortgage, and who do not qualify for social housing.
The one-bedroom flats are made from two 8m x 3.2m modules, with
the twobedroom versions using three modules. Internal corridors
have been omitted to save space, with access gained by external
balconies facing the street. Each flat also has a private balcony,
which overlooks a south facing communal landscaped courtyard. All
flats arrived on site fully fitted-out with kitchens and bathrooms,
wired, plumbed and decorated. Furthermore, the steel panel roof and
the circular entrance, lift and stairwell were also delivered as
modular elements. The construction period was just 10 days.
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Figure 4.4 The Peabody Trusts Murray Grove Development
(Source: Author)
A quality architectural image was again critical to the
developer in order to overcome the perceptions often associated
with system-built housing (Design for Homes, 2006), and so they
appointed an architect, Cartwright Pickard, to improve the design
process. However, the prefabricated construction is expressed
through the Yorkon system, in pre-cast concrete balconies,
steel-rod cross bracing and clip-on terracotta tile cladding, all
of which was assembled on site. Curved perforated
aluminium screens also form a translucent veil in front of the
balconies and stair tower. This tower houses a glazed lift and is
highly visible being located at the junction between the two wings.
Due to its bespoke features, the main contract was awarded to
Kaijima, a Japanese based world leader in prefabricated
housing.
The advantages of the Yorkon modules are better quality control
and reduced construction times. The site work was done with
conventional pile foundations, at the same time as the modules were
being manufactured. This was in fact the first time that Yorkon had
used their modular assembly for housing, previously being used for
classrooms and fast food outlets.
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In recognition of its success, Murray Grove has won a string of
awards since its completion, including: the Housing Design Award
2000; the RIBA Award for Architecture (London region) and the Royal
Fine Art Commission Millennium Building of the Year 2000 (Housing
category). It has also been short-listed for the prestigious
Stirling Prize, all of which would no doubt make Sir John Egan
proud.
4.2.5
Barons Place The Peabody Trust
Barons Place represents The Peabody Trusts third venture in
prefabricated volumetric modular housing. It was completed in late
2004 near to Waterloo Station in central London. Like the
developments before it, fully finished modules were
craned into position in just a few hours.
However, Barons Place is different from the standard. The units
are tiny being intended to be rented out for short periods to key
workers, and perhaps more importantly the system cost just
1,100/m2, roughly two-thirds of normal building costs (Spring,
2004b). The smallest one-bedroom flat at Barons Place is ju