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Design for
Deconstruction:
An Appraisal
Danielle Densley Tingley
Thesis submitted in partial fulfilment of the degree in
Doctor of Philosophy
October
2012
Civil and Structural
Engineering Department
The University of Sheffield
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Declaration
All work presented within this thesis is my own work, except where specific reference has
been made to the work of others.
Danielle Densley Tingley Date
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Summary
This thesis contains an assessment and discussion of the sustainability of design for
deconstruction. As a basis for the work, existing literature was reviewed and the gaps in
existing knowledge highlighted. Environmental assessment methods were identified as a way
to incentivise design for deconstruction.
An analysis of LEED demonstrated minimal achievement of reuse credits, likely due to limited
availability of reused materials. The supply chain can be developed in the future through the
design for deconstruction of all new buildings.
Quantifying the environmental benefits of design for deconstruction was underlined as a key
strategy to encourage designers to consider the incorporation of design for deconstruction. A
methodology was developed to account for designed-in future reuse at the initial design stage.
This is based on a PAS2050 methodology (2008) which shares the environmental impact of an
element over the number of predicted lives. In the course of this work it has been assumed
that the typical building has a fifty year life span, a conservative estimate. Studies in this thesis
limit analysis to a hundred year period, giving a possible two lives for the majority of elements.
The methodology was used as a basis for the calculation of savings that occur by designing for
deconstruction. Initial feasibility studies estimated that a 49% saving in embodied carbon is
accomplished by designing for deconstruction. Having demonstrated the potential scope of
savings, a tool, Sakura, was developed to enable designers to investigate the savings in
embodied energy and carbon for their own schemes. Sakura was used to assess the savings
that could be achieved for a range of case studies. Steel and timber frame structures
demonstrated the greatest potential savings from design for deconstruction. School projects
exhibited the highest savings when the building types were compared.
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Acknowledgements
First and foremost, thanks must go to Buick Davison for supervising this project, for his
support, wisdom and patience throughout. Not to mention letting me go to a conference in
New York!
To the EPSRC, for the doctoral training grant which enabled me to carry out this work
To all of ‘Team Awesome’, for keeping me sane and reminding me to take lunch breaks
To my ‘Morning Motivator’, for making me laugh and weeks of texts to wake me up – this
never would have been handed in on time(ish) without you
To TM for the support and boring yourself with the proof reading
And to anyone else I’ve forgotten.....
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Table of Contents
1 Introduction ........................................................................................................................... 1
1.1 Environmental background ........................................................................................... 1
1.1.1 A definition for Sustainability ................................................................................ 1
1.1.2 The Argument for action ....................................................................................... 2
1.1.3 Global Warming ..................................................................................................... 2
1.1.4 The Argument against action ................................................................................ 3
1.1.5 The potential effects of Climate Change on the environment .............................. 3
1.2 Reducing greenhouse gas emissions ............................................................................. 4
1.3 Embodied energy versus operational energy ................................................................ 4
1.4 Responsibility of products/materials at end of life ....................................................... 6
1.5 LCAs – life cycle assessments ........................................................................................ 7
1.6 Dependency on natural resources (closing the material loop) ..................................... 7
1.7 Importance of reducing CDW & associated legislation ................................................. 8
1.7.1 Ways to reduce CDW – Delft Ladder, recycling vs. reuse ...................................... 8
1.8 Why deconstruct – a broad overview ........................................................................... 9
1.8.1 Key terms relating to deconstruction .................................................................. 10
1.9 Deconstruction of existing buildings ........................................................................... 11
1.10 Conclusions .................................................................................................................. 11
1.11 Aims and outline of thesis ........................................................................................... 11
2 Literature Review ................................................................................................................ 13
2.1 Introduction ................................................................................................................. 13
2.2 Software to assess the feasibility & potential economic benefits of deconstruction . 13
2.3 Deconstruction feasibility of specific construction materials ..................................... 14
2.3.1 Timber .................................................................................................................. 14
2.3.2 Masonry ............................................................................................................... 15
2.3.3 Concrete .............................................................................................................. 15
2.3.4 Steel ..................................................................................................................... 16
2.4 Design for deconstruction in general terms – basic tactics to be applied .................. 19
2.5 Other Systems Developed to Promote the Reuse of Materials .................................. 20
2.6 Environmental Assessment Methods – scope within them for rewarding material
reuse and/or design for deconstruction .................................................................................. 21
2.6.1 BREEAM ............................................................................................................... 21
2.6.2 The Code for Sustainable Homes......................................................................... 22
2.6.3 LEED ..................................................................................................................... 22
2.6.4 Green Star ............................................................................................................ 23
2.6.5 Comparison of Environmental Assessment Methods ......................................... 23
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2.6.6 Proposed Green Demolition Certificate .............................................................. 24
2.6.7 Alternative ways to promote deconstruction ..................................................... 24
2.7 Case Study – reinforced concrete car park structure in seismic zone ........................ 25
2.8 An outline of the major barriers to deconstruction.................................................... 25
2.8.1 Existing perception towards reused materials ................................................... 25
2.8.2 Economic considerations .................................................................................... 26
2.8.3 Is deconstruction more dangerous than demolition for construction workers? 26
2.8.4 Lack of incentives to deconstruct ....................................................................... 27
2.8.5 Re-certification of materials for structural reuse ............................................... 27
2.8.6 Insurance/legal constraints ................................................................................. 28
2.8.7 Lack of supply/demand chains ............................................................................ 28
2.9 Overcoming barriers to design for deconstruction..................................................... 29
2.10 Identification of building types that may be particularly suitable for DfD ................. 30
2.11 Conclusions ................................................................................................................. 31
3 LEED Analysis ...................................................................................................................... 32
3.1 Introduction ................................................................................................................ 32
3.2 Background ................................................................................................................. 32
3.3 Method ....................................................................................................................... 33
3.4 Results and Analysis .................................................................................................... 34
3.4.1 Analysis of Overall Categories ............................................................................. 34
3.4.2 Individual credit analysis: .................................................................................... 35
3.4.3 Credits that seem easiest to obtain .................................................................... 35
3.4.4 Credits obtained by 90+ % of projects ................................................................ 36
3.4.5 Credits obtained by less than 50% of projects .................................................... 38
3.5 Analysis by location ..................................................................................................... 39
3.6 Analysis by building type ............................................................................................. 41
3.7 Update to Version 3 .................................................................................................... 43
3.8 Conclusion ................................................................................................................... 44
4 Development of a Life Cycle Assessment Methodology ..................................................... 46
4.1 Introduction ................................................................................................................ 46
4.2 Overview of Existing Sustainable Building Analysis Tools ........................................... 46
4.2.1 Waste Minimisation Tools: ................................................................................. 46
4.2.2 Embodied Energy and Carbon Calculators for Buildings & Structures ............... 48
4.2.3 General Life Cycle Assessment Tools .................................................................. 50
4.2.4 Environmental impact building analysis tools that use a life cycle analysis
methodology ....................................................................................................................... 52
4.2.5 IMPACT, underdevelopment ............................................................................... 53
4.2.6 Conclusions about existing tools ......................................................................... 53
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4.3 Life Cycle Assessment Methodology ........................................................................... 54
4.3.1 Introduction ......................................................................................................... 54
4.3.2 Life cycle assessment framework ........................................................................ 54
4.3.3 LCA System Boundaries ....................................................................................... 55
4.3.4 Discussion of Life Cycle Analysis Methods .......................................................... 56
4.3.5 Discussion of environmental impact for products with multiple uses ................ 57
4.3.6 Graphical output options for methodology ........................................................ 60
4.3.7 Life Cycle Stages .................................................................................................. 62
4.3.8 Life Cycle Inventory ............................................................................................. 73
4.4 Conclusions .................................................................................................................. 74
5 Feasibility Studies: a quantification of the environmental savings from design for
deconstruction............................................................................................................................. 76
5.1 Introduction ................................................................................................................. 76
5.2 Aims and Objectives .................................................................................................... 76
5.3 Impacts of Design for Deconstruction on the Embodied Carbon of Structural Bays .. 76
5.3.1 Method ................................................................................................................ 76
5.3.2 Composite Bay ..................................................................................................... 77
5.3.3 Partially composite Bay ....................................................................................... 77
5.3.4 Non composite bay .............................................................................................. 78
5.3.5 Comparison of Bay Types .................................................................................... 80
5.4 Impacts of Design for Deconstruction on whole life cycle carbon .............................. 80
5.5 Sensitivity Study of datasets ........................................................................................ 81
5.5.1 Method & initial discussion of Datasets .............................................................. 81
5.5.2 Composite Bay ..................................................................................................... 82
5.5.3 Partially Composite Bay ....................................................................................... 83
5.5.4 Non Composite Bay ............................................................................................. 85
5.6 Conclusions .................................................................................................................. 86
6 Development and use of Sakura.......................................................................................... 88
6.1 Introduction ................................................................................................................. 88
6.2 Technical Background and Setup ................................................................................ 88
6.3 Design for Deconstruction Website ............................................................................ 89
6.4 Use of Sakura ............................................................................................................... 93
6.4.1 Login/Registration ............................................................................................... 93
6.4.2 The Initial Form .................................................................................................... 94
6.4.3 Material Input Options ........................................................................................ 96
6.4.4 Material Specification .......................................................................................... 98
6.4.5 Editing Option .................................................................................................... 101
6.4.6 Embodied Energy and Carbon Results Page ...................................................... 102
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6.4.7 Accessing and Altering Existing Projects ........................................................... 104
6.5 Pilot Trial of Sakura ................................................................................................... 108
6.6 Validation of Sakura .................................................................................................. 109
6.7 Conclusions ............................................................................................................... 111
7 Case Studies ...................................................................................................................... 112
7.1 Introduction .............................................................................................................. 112
7.2 Aims and Objectives .................................................................................................. 112
7.3 Stadium Case Study ................................................................................................... 112
7.3.1 Background ....................................................................................................... 112
7.3.2 Methods & key data .......................................................................................... 112
7.3.3 Mass Breakdown for the whole structure ........................................................ 116
7.3.4 Utilising Sakura for the Stadium Case Study ..................................................... 117
7.3.5 Exploration and Discussion of Results .............................................................. 119
7.4 Warehouse Case Studies ........................................................................................... 122
7.4.1 Warehouse 1, steel frame ................................................................................. 122
7.4.2 Warehouse 2, concrete & timber frame ........................................................... 122
7.4.3 Results ............................................................................................................... 122
7.5 School Case Studies ................................................................................................... 129
7.5.1 School 1, steel frame ......................................................................................... 129
7.5.2 School 2, concrete frame .................................................................................. 129
7.5.3 School 3, composite steel frame ....................................................................... 129
7.5.4 Results ............................................................................................................... 129
7.6 Office Case Studies .................................................................................................... 138
7.6.1 Office 1, composite steel frame ........................................................................ 139
7.6.2 Office 2, concrete frame ................................................................................... 139
7.6.3 Results ............................................................................................................... 139
7.7 Supermarket Case Studies ........................................................................................ 146
7.7.1 Supermarket 1, a steel portal frame ................................................................. 146
7.7.2 Supermarket 2, glue laminated timber frame .................................................. 146
7.7.3 Results ............................................................................................................... 146
7.8 Conclusions ............................................................................................................... 154
8 Discussion .......................................................................................................................... 156
8.1 Introduction .............................................................................................................. 156
8.2 Is Design for Deconstruction truly sustainable? ....................................................... 156
8.2.1 The Environmental Perspective ........................................................................ 156
8.2.2 The Economic Perspective ................................................................................ 157
8.2.3 The Social Perspective ....................................................................................... 158
8.2.4 Whole Picture.................................................................................................... 158
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8.3 Overcoming the barriers............................................................................................ 159
8.3.1 Additional fabrication ........................................................................................ 159
8.3.2 Existing perception towards reused materials .................................................. 159
8.3.3 Economic Considerations .................................................................................. 159
8.3.4 Composite Construction .................................................................................... 160
8.3.5 Performance Guarantees for Reused Materials ................................................ 160
8.3.6 Lack of Legislation/incentives for design for deconstruction ............................ 160
8.4 What could be done? ................................................................................................ 161
8.4.1 Construction types ............................................................................................. 161
8.4.2 Building types .................................................................................................... 162
8.5 What needs to change? ............................................................................................. 163
8.6 Conclusion ................................................................................................................. 164
9 Conclusions and Recommendations.................................................................................. 165
9.1 Conclusions ................................................................................................................ 165
9.2 Recommendations for further work .......................................................................... 166
9.2.1 General Recommendations ............................................................................... 166
9.2.2 Recommendations Related to Sakura ............................................................... 169
10 References ..................................................................................................................... 172
Supporting Appendices ............................................................................................................. 186
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List of Tables:
Table 2.1: Summary of strategies to be employed when designing for deconstruction ______________ 20
Table 2.2: Summary of the barriers that design for deconstruction and material reuse face __________ 29
Table 3.1: Percentage of credits available in each category, comparing the relative weightings of versions
2.0, 2.1, & 2.2 to version 3 ______________________________________________________ 43
Table 4.1: Summary of reuse methodologies _______________________________________________ 58
Table 4.2: Embodied carbon of different building types, adapted from Target Zero (TATA Steel, BCSA,
2012, p. 15) __________________________________________________________________ 64
Table 4.3: CO2 emissions associated with different transport types, adapted from UK Building Blackbook
(Franklin + Andrews Ltd, 2010, p. xvii) _____________________________________________ 66
Table 4.4: General emissions figures for the transport of materials, adapted from UK Building Blackbook
(Franklin + Andrews Ltd, 2010, p. xvii) _____________________________________________ 66
Table 4.5: DEC operational rating bands (Communities and Local Government, 2008b, p. 22) ________ 68
Table 4.6: Example CO2 emissions for different operational ratings _____________________________ 69
Table 4.7: End of life assumptions made in an LCA study, adapted from Target zero report (TATA Steel,
BCSA, 2012) _________________________________________________________________ 72
Table 4.8: Summary of the contributions of the individual life cycle stages _______________________ 75
Table 5.1: Embodied carbon of composite bay ______________________________________________ 77
Table 5.2: Embodied Carbon of partially composite bay ______________________________________ 78
Table 5.3: Embodied carbon of non-composite bay __________________________________________ 79
Table 5.4: Summary table showing the embodied carbon of each bay type _______________________ 80
Table 5.5: Embodied carbon, tonnes CO2e, for all the life cycle stages ___________________________ 81
Table 5.6: Composite Bay: range of embodied carbon values calculated using different datasets _____ 82
Table 5.7: Partially Composite Bay: range of embodied carbon values calculated using different datasets
___________________________________________________________________________ 84
Table 5.8: Non Composite Bay: range of embodied carbon values calculated using different datasets __ 85
Table 6.1: Description of Materials Database _______________________________________________ 88
Table 6.2: Spreadsheet calculation for the embodied values of non -composite bay ________________ 109
Table 7.1: Summary of information for piles and pile caps ____________________________________ 113
Table 7.2: Summary table showing mass of reinforcement within the ground beams ______________ 113
Table 7.3: Masses of concrete and reinforcement in the ground beams _________________________ 114
Table 7.4: Summary showing the mass of materials within the ground floor slab _________________ 114
Table 7.5: Inventory of columns in stadium, showing which are composite and non-composite ______ 114
Table 7.6: Masses of Steel and Concrete Columns __________________________________________ 115
Table 7.7: Masses of Steel Beams within Stadium, showing the different levels they're situated on ___ 115
Table 7.8: Summary table showing the mass breakdown within the floor slabs in different stands and
different levels ______________________________________________________________ 116
Table 7.9: Summary table showing the masses of the roof beams and purlins ____________________ 116
Table 7.10: Mass breakdown of the different elements within the stadium, showing the contribution of
each ______________________________________________________________________ 117
Table 7.11: Mass of different materials in the stadium ______________________________________ 117
Table 7.12: Embodied energy and carbon results from Sakura for the two warehouse options _______ 123
Table 7.13: Embodied energy and carbon results for School case studies ________________________ 130
Table 7.14: Embodied energy and carbon results for Office case studies ________________________ 140
Table 7.15: Embodied energy and carbon results for Supermarket case studies ___________________ 147
Table 8.1: Summary of savings for different building and construction types _____________________ 163
List of Figures:
Figure 2.1: 2012 Olympic Stadium, top tier designed for deconstruction (UKGBC, 2012b) ____________ 17
Figure 2.2: 2012 London Olympic Stadium (UKGBC, 2012b) ____________________________________ 18
Figure 2.3: Vulcan House, Sheffield (Photo credit, David Millington) _____________________________ 18
Figure 3.1: Percentage of Credits obtained in each LEED Category ______________________________ 34
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Figure 3.2: Percentage of projects obtaining specific credits within the Materials and Resources category
___________________________________________________________________________ 35
Figure 3.3: Location of Case Study Projects ________________________________________________ 39
Figure 3.4: Percentage of credits achieved in each LEED Category, sorted according to project’s location
___________________________________________________________________________ 40
Figure 3.5: Percentage of projects obtaining reuse and recycling credits within LEED, sorted by location 41
Figure 3.6: Percentage of credits achieved in each LEED category, sorted according to building type __ 42
Figure 3.7: Percentage of projects gaining reuse and recycling credits, sorted by building type _______ 43
Figure 4.1: System boundaries of the life cycle of a building ___________________________________ 56
Figure 4.2: The embodied carbon of a steel beam spread out over its life span ____________________ 61
Figure 4.3: Embodied carbon of a steel beam, showing how the impact can be spread out between
different lives ________________________________________________________________ 61
Figure 4.4: Graph showing CO2e emissions produced at each life cycle stage of a building __________ 62
Figure 4.5: Graph showing CO2e emissions produced in each life cycle stage of a building, comparing a
building where the structure has been designed for deconstruction with a building where it has
not ________________________________________________________________________ 62
Figure 4.6: Life cycle stages of a building __________________________________________________ 63
Figure 5.1: Effect of the reinforcement embodied carbon factor _______________________________ 79
Figure 5.2: Life cycle embodied carbon for the three design options ____________________________ 81
Figure 5.3: Composite Bay: the impact of different datasets on the embodied carbon of elements within
the bay _____________________________________________________________________ 83
Figure 5.4: Composite Bay: the impact of different datasets on the total embodied carbon of the bay, (A)
shows the total embodied carbon, (B) the embodied carbon per m2 ____________________ 83
Figure 5.5: Partially Composite Bay: the impact of different datasets on the embodied carbon of elements
within the bay _______________________________________________________________ 84
Figure 5.6: Partially Composite Bay: the impact of different datasets on the total embodied carbon of the
bay, (A) shows the total embodied carbon, (B), the embodied carbon per m2 _____________ 85
Figure 5.7: Non Composite Bay: the impact of different datasets on the embodied carbon of elements
within the bay _______________________________________________________________ 86
Figure 5.8: Non Composite Bay: the impact of different datasets on the total embodied carbon of the
bay, (A) shows the total embodied carbon, (B), the embodied carbon per m2 _____________ 86
Figure 6.1: Screenshot of single page of materials database __________________________________ 89
Figure 6.2: Screenshot of design for deconstruction homepage ________________________________ 90
Figure 6.3: Screenshot of About Sakura webpage ___________________________________________ 91
Figure 6.4: Screenshot of Publication webpage _____________________________________________ 92
Figure 6.5: Screenshot of Links webpage __________________________________________________ 93
Figure 6.6: Screenshot of Login page for Sakura ____________________________________________ 94
Figure 6.7: Screenshot of Registration page for Sakura _______________________________________ 94
Figure 6.8: Screenshot of initial page in Sakura _____________________________________________ 95
Figure 6.9: Screenshot of Initial Form to complete within Sakura _______________________________ 96
Figure 6.10: Screenshot of Sakura, showing two different input options _________________________ 97
Figure 6.11: Screenshot of initial info table ________________________________________________ 97
Figure 6.12: Screenshot showing foundation input section ____________________________________ 98
Figure 6.13: Screenshot showing ground floor slab & superstructure input sections ________________ 99
Figure 6.14: Screenshot of upper floor systems input section _________________________________ 100
Figure 6.15: Screenshot of ceiling and roof input sections ____________________________________ 101
Figure 6.16: Screenshot of editing page for the foundations __________________________________ 102
Figure 6.17: Screenshot showing example results for the Embodied Energy _____________________ 103
Figure 6.18: Screenshot showing example results for the Embodied Carbon _____________________ 103
Figure 6.19: Screenshot showing logout page _____________________________________________ 104
Figure 6.20: Screenshot showing existing project in Sakura and the option to edit the specification __ 106
Figure 6.21: Screenshot showing the page to update information about the foundations __________ 107
Figure 6.22: Screenshot showing options to edit the existing project ___________________________ 108
Figure 6.23: Screenshot showing results of non-composite bay in Sakura _______________________ 110
Figure 7.1: Mass breakdown of the different elements in the stadium __________________________ 117
Figure 7.2: Screenshot showing Embodied Energy results from Sakura for the Stadium case study ___ 118
Figure 7.3: Screenshot showing Embodied Carbon results from Sakura for the stadium case study ___ 119
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Figure 7.4: Potential savings from design for deconstruction for the individual elements, embodied
energy shown in (A) and embodied carbon in (B) ___________________________________ 120
Figure 7.5: Stadium - embodied energy (A) and embodied carbon (B) of the different structural elements
showing which benefit for DfD savings ___________________________________________ 121
Figure 7.6: The impact of design for deconstruction on different material types, embodied energy shown
in (A) and embodied carbon in (B) _______________________________________________ 121
Figure 7.7: Comparison of the 2 standard warehouse design options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 124
Figure 7.8: Comparison of the 2 warehouse DfD design options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 125
Figure 7.9: Comparison of warehouse options, embodied energy in (A), and embodied carbon in (B) _ 125
Figure 7.10: Potential savings from DfD of the warehouse options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 126
Figure 7.11: Warehouse, steel frame option, distribution of embodied energy (A) and embodied carbon
(B) for the structural elements __________________________________________________ 127
Figure 7.12: Warehouse, steel frame option, distribution of embodied energy (A) and embodied carbon
(B) for different material types _________________________________________________ 127
Figure 7.13: Warehouse Option 2, distribution of embodied energy (A) and embodied carbon (B) for the
structural elements __________________________________________________________ 128
Figure 7.14: Warehouse Option 2, distribution of embodied energy (A) and embodied carbon (B) for
different material types _______________________________________________________ 129
Figure 7.15: Comparison of the 3 standard design options, (A) shows embodied energy, (B) embodied
carbon _____________________________________________________________________ 131
Figure 7.16: Comparison of the 3 DfD design options, (A) shows embodied energy, (B) embodied carbon
__________________________________________________________________________ 132
Figure 7.17: Comparison of the school options, (A) shows embodied energy/m2 and (B) embodied
carbon/m2 __________________________________________________________________ 132
Figure 7.18: Potential savings from DfD of each of the School options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 133
Figure 7.19: School 1, steel frame, distribution of embodied energy (A) and embodied carbon (B) for the
structural elements __________________________________________________________ 134
Figure 7.20: School 1, steel frame, distribution of embodied energy (A) and embodied carbon (B) for
different material types _______________________________________________________ 134
Figure 7.21: School 2, concrete frame distribution of embodied energy (A) and embodied carbon (B) for
the structural elements _______________________________________________________ 135
Figure 7.22: School 2, concrete frame, distribution of embodied energy (A) and embodied carbon (B) for
different material types _______________________________________________________ 136
Figure 7.23: School Option 3, distribution of embodied energy (A) and embodied carbon (B) for the
structural elements __________________________________________________________ 137
Figure 7.24: School Option 3, distribution of embodied energy (A) and embodied carbon (B) for different
material types _______________________________________________________________ 138
Figure 7.25: Comparison of the 2 standard office design options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 141
Figure 7.26: Comparison of the 2 office DfD design options, (A) shows embodied energy, (B) embodied
carbon _____________________________________________________________________ 142
Figure 7.27: Comparison of the office options, (A) shows embodied energy/m2 and (B) embodied
carbon/m2 __________________________________________________________________ 142
Figure 7.28: Potential savings from DfD of each of the Office options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 143
Figure 7.29: Office Option 1, distribution of embodied energy (A) and embodied carbon (B) for the
structural elements __________________________________________________________ 144
Figure 7.30: Office Option 1, distribution of embodied energy (A) and embodied carbon (B) for different
material types _______________________________________________________________ 144
Figure 7.31: Office Option 2, distribution of embodied energy (A) and embodied carbon (B) for the
structural elements __________________________________________________________ 145
Figure 7.32: Office Option 2, distribution of embodied energy (A) and embodied carbon (B) for different
materials ___________________________________________________________________ 146
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Figure 7.33: Comparison of the 2 standard Supermarket design options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 148
Figure 7.34: Comparison of the 2 Supermarket DfD design options, (A) shows embodied energy, (B)
embodied carbon ____________________________________________________________ 149
Figure 7.35: Comparison of the Supermarket options, (A) shows embodied energy/m2 and (B) embodied
carbon/m2 _________________________________________________________________ 150
Figure 7.36: Potential savings from DfD of each of the Supermarket options, (A) shows embodied energy,
(B) embodied carbon _________________________________________________________ 150
Figure 7.37: Supermarket 1, steel frame, distribution of embodied energy (A) and embodied carbon (B)
for the structural elements ____________________________________________________ 151
Figure 7.38: Supermarket 1, steel frame, distribution of embodied energy (A) and embodied carbon (B)
for different material types ____________________________________________________ 152
Figure 7.39: Supermarket 2, timber frame, distribution of embodied energy (A) and embodied carbon (B)
for the structural elements ____________________________________________________ 153
Figure 7.40: Supermarket 2, timber frame, distribution of embodied energy (A) and embodied carbon (B)
for different materials ________________________________________________________ 154
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1 Introduction
With increasing urbanisation and resource consumption, a different approach to the built
environment needs to be taken to ensure sustainability. When concerns about carbon
emissions and the quantities of waste sent to landfill are added to this, the problems seem
insurmountable. These issues and their connection with the built environment are introduced
and discussed through this chapter. Tactics such as deconstruction, design for deconstruction
and material reuse are introduced as positive steps that can be taken to combat carbon
emissions, reduce resource consumption and avoid waste to landfill. This thesis reviews the
strategy of design for deconstruction in particular, examines its potential and explores how
this method could contribute to a sustainable future.
1.1 Environmental background
Climate change is an unavoidable issue and, irrespective of to what extent humans have
accelerated the process or to what degree it is a natural cycle, it is a topic for serious
discussion. It would seem to be irrefutable that the earth is getting warmer (UNEP, 2007) and
that this is going to have serious implications for the planet and all organisms that inhabit it.
Even though it is too late to completely reverse the effects (UNEP, 2007) the prevailing opinion
is that action should be taken now to minimise temperature increases and the associated
changes to the Earth.
The recent Earth Summit in Rio de Janeiro gathered heads of state and government from
around the globe to discuss the implications of climate change on the world population and
future generations. Whilst a common vision for the future was presented (UN 2012), there was
a significant lack of binding commitments that will turn these ideas into reality, which has led
to criticism from some Non Governmental Organisations (NGOs) (UKGBC, 2012a).
If an optimistic view is taken that governments, NGOs, businesses and individuals will work
together in pursuit of this ‘vision’, then it is important to examine and define several crucial
related issues: a definition for sustainability, arguments for and against climate change, the
effects of climate change and the potential for combating and minimising these consequences.
The work presented in this thesis explores opportunities within the built environment to help
attain this vision.
1.1.1 A definition for Sustainability
Many documents and papers remain quite vague or ambiguous on what is actually meant by
sustainability. Often it is discussed in terms of sustainable development or environmental
sustainability without these terms being clearly defined. Indeed according to Johnston, et al.
(2007) there are as many as three hundred different definitions for sustainability and
sustainable development. Referring to the dictionary is not particularly helpful either. The
Oxford dictionary defines sustainable as ‘able to be sustained’ with the secondary meaning ‘of
industry, development, or agriculture avoiding depletion of natural resources’ (Oxford English
Dictionary, 2008). From this one might conclude that to be sustainable involves being able to
indefinitely continue behaving in a certain way without depleting natural resources. However,
it could be argued that sustainability involves more than not depleting natural resources. The
Global Environmental Outlook report from the UN comments on ‘the need for a sustainable
way of life which not only addresses current environmental challenges but also ensures a
secure society well into the future’ (UNEP, 2007, p.4). This alludes to the dual considerations of
protecting/maintaining the environment whilst also considering the development of society.
Johnston et al. (2007), base their argument for sustainability around the TNS system conditions
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(named after The Natural Step organisation that is promoting these ideas). These four system
conditions are outlined as follows:
“in the sustainable society, nature is not subject to systematically increasing…
1. ….concentrations of substances extracted from the Earth’s crust
2. ….concentrations of substances produced by society
3. ….degradation by physical means and
4. People are not subject to conditions that systematically undermine their capacity to meet their
needs” (Johnston et al, 2007, p.3).
This is not to say that humans can no longer extract natural resources from the Earth, but that
it should be done at a rate which can be maintained without causing permanent damage to
the planet. This definition seems to be a fairly concise summary for what can be considered to
be sustainable development; this also draws parallels with the often quoted definition for
sustainable development from the Brundtland Report (1987, chapter 1, point 49):
‘development that meets the needs of the present without compromising the ability of future
generations to meet their own needs’. In addition to these thoughts on sustainable
development, the author feels that it is important to consider the preservation of the huge
range of other species that inhabit the planet and the adverse affects human actions often
have on these. The human race is reliant on biodiversity for survival and should not treat the
environment and those species that reside within it as expendable resources.
1.1.2 The Argument for action
The Brundtland Report was the first major document to turn peoples’ attention to the
potential effects of climate change; written over two decades ago, it highlighted key issues
that the planet and its inhabitants would potentially face in the future if the human race
continued to live in an unsustainable manner. However, the resulting action by governments,
businesses and the general population has been slow to produce a unified result. Some
progress has been made, particularly with regards to the emission of pollutants that cause acid
rain and the reduction of the use of substances that cause depletion of the ozone layer. The
success of the latter, following the Montreal protocol (UNEP, 2007), is considered a good
example of how international cooperation can be achieved with the desired results. However,
achieving this level of agreement has proved to be more problematic with the Kyoto Protocol –
which predominately addresses carbon dioxide and other greenhouse gas (GHG) emissions.
Continuing meetings and discussions by world leaders, both at the Copenhagen convention
and Rio+20 have resulted in suggestions and ideas but no measurable targets to build on the
Kyoto Protocol (UN, 2012). Change is needed as the general consensus of scientists is that it is
the build up of greenhouse gases in the atmosphere that is causing global warming and the
associated climate change effects. According to the Global Environmental Outlook report from
the UNEP (2007) the average temperature of the Earth has risen by 0.74°C during the last
century; with predictions for a future rise of 4°C if green house gas emissions are not
addressed immediately.
1.1.3 Global Warming
This is the term used to describe the effects when GHG gases (main examples include carbon
dioxide, methane, nitrous oxide and water vapour) become trapped in the atmosphere (IPCC
2001). These gases absorb radiation that is trying to escape the Earth, thus trapping it within
the atmosphere which then slowly increases the temperature of the planet. It is also thought
that once temperature increases start to occur this can trigger further releases of carbon
dioxide from natural reservoirs. In addition, the warmer the atmosphere is, the more water
vapour (a GHG) it can hold, further increasing the global warming effect.
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The energy sector is a major producer of carbon dioxide and although an increased use of
renewable technologies and the use of carbon capture and storage techniques within power
stations that burn fossil fuels has reduced the CO2 emitted per amount of energy produced,
the total energy requirements are high and predicted to continue to rise. With populations at
an all time peak (UNFPA, 2011), energy usage is at a premium. According to the UNEP report
(2007) the global population has risen by 1.7 billion between the time of the Brundtland report
(1987) and the publication of the UNEP report (2007) – with the largest increases in Asia and
Africa. Not only is the population increasing, but peoples’ pattern of living is changing, with
increasing urbanisation. This in itself is causing further problems as ‘cities create heat islands
that alter regional meteorological conditions and affect atmospheric chemistry and climate’
(UNEP, 2007, p.50).
1.1.4 The Argument against action
Whilst the majority of scientists seem to have now come to the conclusion that climate change
and global warming are at least being accelerated by human emissions/pollution, some still
disagree that the human impacts in this area are significant. Florides and Christodoulides
(2008), argue that the temperature increases that the planet is currently experiencing are
nothing more than natural fluctuations and that similar spikes have happened in the past.
Their paper on ‘Global Warming and Carbon Dioxide through Sciences’ goes further, arguing
that there is no significant evidence to link increases in the concentration of carbon dioxide to
global warming.
1.1.5 The potential effects of Climate Change on the environment
Having briefly examined the arguments for and against human influence on climate change,
this thesis adopts the position that human emissions are accelerating if not causing global
warming and that the only responsible course of action for the well-being of the planet and
future generations is to significantly reduce impact on the Earth, by among other things
reducing green house gas emissions. The following paragraphs outline some of the potential
effects as presented in the Global Environmental Outlook from the UNEP; emphasising the
importance of taking action now, before the effects are completely irreversible.
Increasing temperatures will cause ice in the Polar Regions to melt as these areas are
susceptible to the slightest temperature increase. This in turn produces rising sea levels, by up
to 0.59m in a worst case scenario (BBC, 2009). A rise in sea levels will instigate wide spread
flooding to low-lying regions, displacing thousands of people from their homes and destroying
the natural habitat of many species. Global warming could also change circulation currents
within the ocean, alterations for example to the movement of the Gulf Stream would cause
climates within Europe to dramatically change. In addition, changes in water temperature will
affect the ecosystems that reside within, potentially disturbing these to a point from which
they cannot recover; wiping out species and causing further poverty in developing nations
which rely on these as a food source.
Other effects include the alteration of precipitation patterns, increasing drought and flooding
which not only cause large problems themselves, but when combined with land degradation
can trigger an escalation of desertification and mudslides. Not only humans will feel these
effects, many species are suffering from increased risk of extinction, with biodiversity in some
areas seriously threatened.
The effects of Global Warming across the world differ, with the Polar Regions seeing
temperature increases that are over double the global average, this has a knock-on effect with
rising sea levels for the rest of the planet. The UN report suggests that those already in the
worst position will be most affected, stating that ‘poverty and environmental degradation have
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a cause-and–effect relationship, and can fall into a cycle that is difficult to reverse’ (UNEP,
2007, p.201).
1.2 Reducing greenhouse gas emissions
Given the predictions for the planet if business as usual continues, strategies need to be
devised to limit GHG emissions and mitigate the damage already caused. A move towards
renewable energy sources would help, but it would seem highly unlikely that renewable
sources alone can supply current energy demands, let alone the increases in demand that will
occur. Furthermore, many renewable sources are not yet economically viable for large scale
use. David MacKay’s book ‘Sustainable Energy – without the hot air’ (2008) examines this issue
with remarkable clarity, looking at the areas within Britain that would be required for wind
farms, solar panels etc. and then comparing the potential energy that could be produced, with
an estimated energy demand per person in Britain, and concludes that renewable energy is
only part of the answer. Nuclear powered energy plants are likely to also become part of the
solution, although whilst these do not produce carbon dioxide there is the radioactive waste
produced that must be dealt with, some of which must be contained and stored for a thousand
years before it may be safe. Ground source heat pumps could become an efficient way to heat
buildings, thus reducing the electricity/gas required to do this. However, it will take time and
substantial funding to attain these goals. Carbon capture and storage may effectively buy more
time to continue using fossil fuels whilst reducing carbon dioxide emissions and making the
transition to more sustainable energy sources. MacKay (2008) also suggests that tax incentives
may help encourage the transition to sustainable energy production / product design. The idea
of a carbon tax is also raised, – designed to make it too expensive to continue emitting current
levels of carbon dioxide. The concept of a carbon tax is increasingly debated (Bordigoni et al.,
2012; Tolis & Rentizelas, 2011) and looks likely to become a reality in the future.
Making the move to sustainable energy sources seems possible, particularly with the
appropriate incentives and funding in place. This has strong implications for the building sector
- which accounts for 30 – 40% of global energy use according the Global Environmental
Outlook report from the UNEP (2007). MacKay (2008) demonstrates that energy usage within
buildings can be reduced, (with corresponding reductions in carbon dioxide emissions) either
with increased insulation, double/triple glazing, and reducing draughts in old buildings or
simply designing and building new, more energy efficient ones. One can also reduce personal
energy usage within buildings by sensible practices like turning lights off, or not leaving
electronic appliances on standby. However, what about the energy embodied within the
building and the carbon dioxide emissions associated with that? 3.2% of global emissions are
from the manufacture of iron and steel, whilst 4% are from cement factories (Fachinger, 2012)
and much of these materials will go into the built environment. There are design techniques
and strategies that can be introduced to target the impact these have and these are areas that
can be influenced by a Structural Engineer when specifying materials.
1.3 Embodied energy versus operational energy
Whilst there are large amounts of energy and carbon dioxide emissions associated with
building materials, and there are increasing amounts of research work on reducing embodied
carbon, the government’s main focus is on reducing the operational energy of buildings. There
are targets for new build homes to meet the zero carbon standard by 2016 (Communities and
local government, 2008 a, p. 77) and new non-domestic buildings to do the same by 2019
(Communities and local government, 2008 a, p. 65), although there is debate about the latter.
The zero carbon standard is not truly zero carbon but targets only those emissions that are
within the purview of building regulations (Shapps, 2011). This regulated energy use includes
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that for lighting, heating, ventilation and water heating. Unregulated emissions, which are
outside the current scope, include the energy used for household electrics and for cooking.
These are estimated to account for one third of emissions from the home (Zero Carbon Hub,
2011).
This new definition is a significant step backwards from the original aims of a zero carbon
home, where the predicted energy use of appliances in the home was to be accounted for,
potentially through the provision or connection of on-site low/zero carbon technologies
(Communities and local government, 2008a). Instead building regulations will focus on the
energy efficiency of the building fabric, with higher standards to occur in 2013 and 2016
(Target Zero Report, 2010). This also means that homes will be designed to this standard from
2016 but will not be performing at this level until a year or so later when the new homes have
been built.
Ideally, this standard should be considered in conjunction with embodied energy and the
impacts it may have on it. In many cases achieving zero carbon emissions will result in
increased embodied energy of the building (Brocklesby, 1998); this emphasises the importance
of considering these two issues in unison for the optimal outcome. Whilst some consider the
embodied energy of a building to only be 8-10% of the total energy usage in the whole
building’s life (Kingspan, 2010), other studies (Sturgis & Roberts, 2010) estimate for some
building types that the embodied carbon could contribute up to 60% of the whole life carbon.
There is a growing awareness in this area, for example mgb Architecture + Design state that
‘the effects of embodied energy in structures are significant, and they will command our
attention more as buildings become increasingly energy efficient (thereby changing the
operating versus embodied energy ratio)’ (p.26 2012). Furthermore, recommendations were
made to the government by the Innovation and Growth Team (a steering group, with experts
from industry) that standardised methods of assessing embodied carbon should be developed
so that this can be included within feasibility studies (IGT, 2010).
There is a strong argument that the embodied energy should be included in the definition of
zero carbon buildings. The Green Building Council Australia state that ‘buildings need to have
zero emissions in their construction, operation and embodied energy to be truly carbon
neutral’ (2008). It seems likely then that it is not a question of if embodied energy and carbon
should be minimised but a case of when legislation will dictate that this must be done. It would
therefore seem sensible to start considering ways in which this might be achieved now.
One way in which the embodied energy of building could be reduced is to minimise the energy
required to make ‘new’ materials in the first place. Researching different ways of
manufacturing materials, ways that are less energy intensive, is one option. Developing
current processes to be more energy efficient is another choice, and changing the source of
the energy used in the manufacture to renewable energy forms would also minimise the
embodied carbon of products. However, detailed consideration of these issues is outside the
scope of this thesis.
An alternative to the above approach is to reduce the embodied energy of materials through
recycling and material reuse. Recycling materials, rather than creating them from raw
materials, is often less energy intensive and so the resulting materials will have a lower
embodied energy. Material reuse would reduce embodied energy even more. This can occur
when building materials have been salvaged so that they can be reused again in their current
form – some repair or repainting may be required, but overall the process would require
significantly less energy than the manufacturing of ‘new’ material. According to Edmonds and
Gorgolewski ‘reuse of components allows for complete retention of embodied energy,
requiring energy only for transportation to their next use’ (Unknown date, p.1). An important
issue involved in material reuse is ensuring that the materials do not get damaged during the
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demolition of the original building. Ideally for maximum material recovery the building should
be deconstructed rather than demolished; this involves the systematic taking apart of the
building piece by piece, and therefore minimises damage to materials. Further to this, where
buildings have been designed for deconstruction an even greater material yield may be
achieved.
1.4 Responsibility of products/materials at end of life
In order for materials to be reused or recycled at the end of their useful life, one needs to
question whose responsibility it is to take charge of this. Current practices imply that for most
packaging containers it is the consumer who has this duty: to recycle the glass, cardboard and
plastics that the product they bought was stored in. Generally if electronic products break,
either the owner gets them repaired or will take them to the tip. It is not normally possible for
the owner of the product to take it apart and recognise what parts can be reused, which
should be recycled and which materials are potentially hazardous. In these cases a consensus
seems to be forming that the manufacturer or producer is the most appropriate person to take
responsibility. Given they designed the product in the first place, they are potentially best
equipped to disassemble it for reuse or recycling, and legislation is moving in this direction
(Europa 2009).
This kind of practice is becoming increasingly important within the product design world. Some
companies have introduced voluntary reuse/recycling schemes. For example, Kodak pays film
developing companies to return their single use cameras to them so that they can be taken
apart and the parts either reused or recycled (Rose et al., 2001, p.189). Assessments can be
carried out on products to investigate what the best end of life scenario is, either for the whole
product, or for the component parts, as different parts may have different life-spans. Rose et
al (2001) outline a tool (ELDA – End-of-Life Design Advisor) to help identify the best practice at
the end of life of products. This recommends whether reuse, remanufacture, recycling with
disassembly, recycling without disassembly or disposal is the most appropriate scenario. Using
this kind of practice can enable companies to achieve higher levels of eco-efficiency in the
manufacturing of their products.
This type of practice and thinking is being encouraged by the EU, which has passed legislation
(directive 2002/96/EC, - the waste electrical and electronic equipment directive, WEEE, to
minimise electrical and electronic equipment waste (Europa, 2008)), with the aim to improve
recycling and reuse of these products or the components of these products. The producers, or
in some cases retailers, have to fund take back programs, providing information to consumers
on how and where to take their products back to, and this must be free of charge for the
consumer. The idea is that this will encourage the producers to design and manufacture
equipment that can be easily recycled or reused, thus minimising the amount of electronic
equipment reaching the waste stream (Europa, 2009). In many cases designing for disassembly
can facilitate this type of practice, as it enables products to be easily taken apart so that the
components can be reused or recycled depending on their useful life span.
This idea of using valuable resources again and again without down-cycling them is an
important issue. It can result in less extraction of natural resources being required, less waste
sent to landfill and is likely to be of economic benefit to the manufacturer. It essentially uses
the idea of cradle to cradle design rather than cradle to grave i.e. what could be regarded as a
waste product is seen as the raw material for another process. Braungart and McDonough
(2008) present this idea in their book ‘Cradle to Cradle – re-making the way we make things’
and explore the concept of fundamentally changing the way products are designed so that
they can either be safely reused/recycled or disposed of in a way that is beneficial to the
environment. They also explore the idea of leasing a product for a set period of time rather
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than buying it outright. This means that the manufacturer retains ownership for the materials
of the product and gets the product back once the customer no longer has use for it, these
materials can then be used as the feedstock for a new product. The WEEE directive from the
EU potentially encourages this type of design. However the manufacturers need to fully exploit
this to their advantage, recovering the maximum amount of materials for reuse and not just
those that it is convenient to do so. In many cases this will require a complete re-visitation to
the design process, but if it results in true cradle to cradle design, it could be beneficial both
economically and for the environment.
1.5 LCAs – life cycle assessments
Life cycle assessments (LCAs) are becoming an important environmental measure of products
that are designed for cradle to grave use. These can be used to shape manufacturing or
construction processes by identifying areas that have the largest environmental impact. A
major challenge in conducting an LCA is defining and limiting the scope of the project, which is
the first of four main phases of a study, the goal and scope definition phase. After this is the
inventory analysis phase, which is followed by the impact assessment phase and finally the
interpretation phase concludes the study (BS EN ISO 14040: 2006). An LCA considers the whole
life of a product, from the extraction of raw materials through to its disposal at end of life. It is
the system boundaries that define what is included in the assessment and according to BS EN
ISO 14044:2006 any aspect that could significantly influence the outcome of the study should
be included. It can however be challenging to decide this and an important part of the study is
to explain the cut-off criteria. Increasing numbers of products give their LCI (life cycle
information) data as part of their product specifications – enabling consumers to choose
materials or products with lower environmental impacts.
1.6 Dependency on natural resources (closing the material loop)
It is widely accepted that there is too much dependence on natural resources to supply energy
needs and that a move away from coal, oil and natural gas is essential. This does however raise
the question as to whether the human race is too dependent on natural resources for all the
materials that are used in everyday life. Remembering the earlier definition of sustainability as:
nature not being ‘subject to systematically increasing concentrations of substances extracted
from the Earth’s crust’ (Johnston et al, 2007, p.3), it would seem that continued extraction of
natural materials is unsustainable. Indeed, Brocklesby (1998) identifies the depletion of
resources as a key point of concern in terms of the impact of human activities on the
environment. However, natural materials play a crucial part in every industry; the building
industry for example, is extremely reliant on them. Without iron there would be no steel;
without trees, no timber; without aggregate, no concrete, which does not leave many
structural materials! If the human race is to minimise its extraction of natural resources then
the solutions seem to be to either stop using natural materials (which would appear to be
impossible) or to reuse the materials that have already been extracted. This ideology is known
as closing the material loop. The concept being that at the end of a building’s life the materials
contained within are separated out, so that they can either be reused in their current form or
recycled into another form. Steel provides a good example; it is easy to separate from other
construction materials due to its magnetic properties and can be reused or recycled. Generally,
large amounts of structural steel are recycled; in Australia 97% of all structural steel is reused
or recycled (ASI, 2010) but this input of recycled steel cannot meet the demands for new steel,
so raw materials still need to be extracted, as is the case for most developed countries. Similar
practice should be able to be implemented in the concrete sector. Estevez et al (2003), as part
of CIB report 287, conclude that crushing and recycling old, already used concrete for
aggregate has less of an environmental impact than quarrying and crushing natural aggregates,
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particularly in terms of CO2 emissions. It has the added advantage of reusing a material that
otherwise might go to landfill, and reducing dependence on natural resources. Reducing
demolition waste is an integral part of closing the material loop.
1.7 Importance of reducing CDW & associated legislation
The construction and demolition sectors produce the most waste compared to any other
sector. With less and less space for landfill and the need to preserve natural resources, it is
important that increased reuse and recycling of building materials is not only encouraged but
enforced.
According to a report on the Management of Construction and Demolition Waste by the SCI
(2009), around 90 million tonnes of non-hazardous construction and demolition waste (CDW)
is produced per year. The industry also produces the largest amount of hazardous waste
compared to any other sector. It can therefore be seen that the industry as a whole needs to
make a concerted effort to reduce CDW. The EU and UK government recognise this and
legislation is starting to come into place, alongside waste prevention programs. The EU Waste
Framework Directive (European Parliament, 2008) gives the UK the target of reusing and
recycling at least 70% of CDW by 2020. Whilst this may sound challenging, some EU member
states like the Netherlands, Belgium and Denmark already recycle around 90% of their CDW,
much of it as a road-base in new road construction (Dorsthorst & Kowalczyk, 2003). In recent
years Germany has also managed to dramatically increase the amount of CDW that is reused
or recycled. This is the direction the UK needs to be heading in to meet EU targets. According
to an SCI report (2009), the government has a series of goals with regards to CDW: to help the
construction industry improve its economic efficiency by reducing waste from every stage of
the construction process, to encourage the sector to close the resource loop by reusing and
recycling CDW and finally to increase sector demand for reused/recycled materials, therefore
improving the chances of contractors salvaging materials as there are potentially economic
benefits.
Examples in the Netherlands and Germany have shown that strict legislation from the
Government can make a significant difference in this area. Both countries have a ban on CDW
that can be recycled or reused being taken to landfill. Only hazardous or non-recyclable
materials may be disposed of in this way. The difference this strength of legislation can make
can be seen in the reuse/recycling percentages for CDW in Germany before and after the
legislation came into place. According to a WRAP report (2009) of the legislation and planning
developments concerning demolition in selected European Countries, Germany now recycles
or reuses 80% of CDW. A significant difference can be seen if this is compared to the 17% that
was being recycled before the new legislation came into place (Dorsthorst & Kowalczyk, 2003).
It would be interesting to see if similar legalisation within the UK would produce similar results
or would also increase fly-tipped waste – according to the SCI report construction waste is
already thought to account for a third of fly-tipped waste. Currently, within the UK, landfill tax
is the main incentive to recycle or reuse CDW but it is debatable whether this will sufficiently
reduce CDW, or whether stricter legislation or a higher tax would be more effective.
Nevertheless, it is also possible that encouraging reuse and recycling of CDW and emphasising
the potential economic benefits of this might result in a significant reduction in CDW taken to
landfill.
1.7.1 Ways to reduce CDW – Delft Ladder, recycling vs. reuse
There are a series of methodologies that look at waste management and the reduction of
CDW. At the most basic level there is the principle of the three R’s – reduction, reuse and
recovery (the final R is sometimes altered to recycle). First the amount of waste produced
should be reduced; next, objects that can be reused should be; and finally that the waste
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should be sorted so that items are recycled, composted or as a final option incinerated to
generate energy. The three R’s are a principle employed in Japan and in South Korea according
to the UNEP report (2007). In the Netherlands a more complex and detailed waste
management strategy has been developed, called the Delft Ladder. This has also been adopted
in the UK, although it has been simplified and renamed as the Waste Management Hierarchy.
1.7.1.1 The Delft Ladder
This outlines a waste management strategy that can be applied not only to waste from the
construction and demolition industries but as a general waste management strategy. It is a ten
step hierarchy that was developed from the Ladder of Lansink (Dorsthorst & Kowalczyk, 2003)
and should be considered at the design stage of buildings/products as well at the end of life.
The Delft ladder is outlined as follows:
1. Prevention (essentially the same as reduction in the three R’s principle) - future waste can be
reduced at the design stage, by careful consideration of material choices and fixtures.
2. Construction Reuse / Object renovation – the principle behind this step is to renovate and
improve existing structures/objects rather than demolishing them/taking them to landfill, to
improve the existing product model or building rather than buying a new product or
constructing a new building.
3. Element Reuse – considers taking apart a building/product and reusing the individual
component parts, rather than letting them go to waste. Designing the building/product for
deconstruction will maximise the output of useful elements.
4. Material Reuse / Recycling – separating materials out after deconstruction of the
building/product, those materials that cannot be reused in their current form should be
recycled.
5. Useful New Application – this is often called down-cycling, reusing the element or material for
a new purpose, for example crushing concrete and reusing it as a road-base.
6. Immobilisation with useful application – turning a potentially polluting or harmful material
into a harmless new material, for example the use of pulverised fuel ash in concrete.
7. Immobilisation – rendering a potentially dangerous material harmless before sending it to
landfill.
8. Incineration with energy recovery – burning combustible waste materials and recovering the
energy produced.
9. Incineration – burning combustible waste materials.
10. Landfill – waste materials taken to landfill – this should be a last resort (Dorsthorst &
Kowalczyk, 2003; Addis & Schouten, 2004).
1.8 Why deconstruct – a broad overview
Burgan and Sansom state that ‘sustainable development requires that the end of life impact of
buildings is minimised’ (2006, p.1182) Deconstruction is a very good way of minimising the end
of life impact of a building. Step 3 on the Delft ladder, ‘element reuse’, can be achieved by
deconstructing buildings rather than demolishing them, as deconstruction involves taking the
building apart piece by piece which means the parts are much more likely to be reusable. This
tactic can be used for both existing buildings and in the design of new buildings.
Deconstruction of existing buildings can be difficult and may not yield high recovery rates.
Analysis of the building techniques and the site conditions can help assess whether it is worth
deconstructing an existing building. Guy (2001) presents a piece of software that can assist in
deciding if it is worth deconstructing an existing building. This tool was mainly developed for
wood structures, and assesses the economics as well as the practicality of deconstruction for
specific projects. The potential difficulties in deconstructing existing buildings demonstrate the
importance of considering deconstruction at the design stage; this concept is known as design
for deconstruction or DFD for short. If the buildings are designed with deconstruction in mind,
then they should be easier to take apart, yield higher material recovery rates, and less material
damage should be incurred. As Gorgolewski (2006, p.493) says ‘it is desirable that as many
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components of a building as possible be extracted from the waste stream for reuse at the end
of their useful life.’
Deconstruction as opposed to demolition can have a number of benefits that are built on the
idea of reusing materials. According to Chini and Nguyen (2003) the benefits of deconstruction
can be split into three main categories: social, economic and environmental. The social
benefits are that deconstruction will provide employment opportunities, as well as further
training prospects for those already involved in the construction industry. It will also produce
materials which should be low cost and good quality, these should ideally be used within the
community in which the deconstruction takes place. Deconstruction may also generate other
benefits for those sectors that support it e.g. if large amounts of materials are salvaged then it
may provide the possibility of a local shop that specialises in reused materials. A number of
studies have been done to assess the potential of reused material shops. Odom (2003)
concluded that reused material shops can be successful if there is sufficient deconstruction in
the area or if the company is affiliated with a deconstruction company. Odom states that
‘wherever building material waste is generated, used building material stores also need to
exist’ (2003, p.185). This idea of selling the salvaged materials links back into Chini and
Nguyen’s thoughts on the economic benefits of deconstruction, selling the materials is one
benefit – if the contractor sells these themselves then the return is additional profit for the
job. Some older materials that can only be found in existing buildings may also be of higher
quality or have better workmanship than new materials and so these old materials may sell for
a higher price. Deconstruction can also allow demolition contractors to expand their business
and potentially employ more labourers. Finally, the environmental benefits of deconstruction
according to Chini and Nguyen (2003) are that it allows reuse of materials which both saves
energy and minimises the waste sent to landfill, it preserves natural materials (to some extent)
and potentially can decrease disturbance to the site. According to Kestner and Webster, design
for deconstruction ‘is arguably the most important green design strategy for achieving material
sustainability through closing the materials loop’ (2010). This in combination with the potential
energy savings makes design for deconstruction a very important sustainability strategy for
future buildings.
A WRAP report has put figures to the potential environmental savings that can occur when
elements are reused stating that there is a ‘96% environmental impact saving by reclaiming
and reusing 99 tonnes of steel’ (WRAP, 2008, p.5) [when compared to new steel]. Even if the
new steel section has 60% recycled steel within it, the component will still have twenty-five
times the environmental impact of a reused section. Perhaps more surprisingly, there is a 79%
environmental impact saving when reclaiming and reusing timber (WRAP, 2008, p.5).
1.8.1 Key terms relating to deconstruction
Hobbs and Hurley (2001) identify and define certain key terms associated to deconstruction.
Demolition is described ‘as a process of intentional destruction’ (Hobbs & Hurley, 2001, p.98).
Disassembly and deconstruction are both explained as processes which systematically take
apart components, trying not to damage them, with deconstruction having the specific
intention of reusing the components after recovery. Refurbishment is the process of upgrading
or the replacement of a number of components or services with the intention of improving
building performance. Retrofit is predominantly an American term, which describes a ‘change
of use or purpose after construction from which a building was designed’ (Hobbs & Hurley,
2001, p.98). The final term described by Hobbs and Hurley (2001) is an adaptable building,
which is a structure designed for flexible use – it can be easily changed to accommodate
different purposes.
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1.9 Deconstruction of existing buildings
The current building stock is substantial and contains lots of valuable and potentially
salvageable materials. Many of the buildings in the UK in particular are also very old, not very
energy efficient and therefore cost large amounts of money and energy to maintain. There
comes a point when it is necessary to question whether one should continue to maintain and
renovate existing buildings, as point 1 of the Delft ladder suggests should be done. When does
it become better for the environment to remove the existing buildings and rebuild? This topic
is suggested as an area for further work, see Recommendation 5. If one is to only consider
demolishing, then there is the significant issue of the large amounts of waste that are likely to
go to landfill. However, deconstruction provides a valid alternative that can potentially make
the removal of existing, non-efficient buildings a lucrative and environmentally friendly option.
If the deconstruction is carefully planned, then large amounts of material can be salvaged and
potentially sold, and the building components can often be reused, thus significantly reducing
the amount of waste sent to landfill. Potentially, new buildings on the same site could reuse
the materials/components from the earlier structure, therefore minimising transport costs.
There would however, need to be a specific design intention to do this and it would need to be
considered at an early stage. The replacement of an old building for a new energy efficient
structure can have significant energy savings in the operation of the building and if the new
building is reusing components then it can also be said to have a minimised embodied energy.
However, deconstruction is not a feasible option for all existing structures because it will
depend on materials choices and the type of fixings/jointing and connections used throughout
the project. Work has been done to develop a number of tools to help assess the feasibility of
the deconstruction of existing buildings.
1.10 Conclusions
This initial chapter sets the scene for the work contained in this thesis. Major topics of concern
are discussed, highlighting why new attitudes towards building design are required.
Aims of work are now discussed and an outline of the thesis given to guide readers to key
areas of interest.
1.11 Aims and outline of thesis
Conducting an extensive literature review (Chapter 2) was the first step to ascertain gaps in the
work on design for deconstruction. It was once this was conducted that specific targets were
set for the PhD. These targets form the agenda for the rest of the work. Aims of the PhD
include:
Development of a methodology to account for designed-in future benefits
Utilisation of this methodology to quantify the environmental savings that result from design
for deconstruction and subsequent material reuse. The methodology will be applied to case
studies. Initial investigations will explore potential savings within a single structural bay. Further
studies will analyse the impacts of incorporating design for deconstruction into a series of
structures. The work aims to identify materials and building types that may be best suited to
design for deconstruction and future material reuse.
Creation of a tool, based on the above methodology, will allow designers to explore potential
benefits of design for deconstruction within their own schemes.
The aims of the PhD build on each other and are addressed throughout the thesis. The
following paragraph outlines the contents of the thesis, within which the aims are dealt with.
Chapter 2 contains the literature review, which encompasses the environmental background
and outlines work already conducted in design for deconstruction and material reuse. A study
exploring LEED, an environmental assessment method, is discussed in Chapter 3. This includes
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an analysis of why material reuse credits appear hard to achieve. A methodology is proposed
for how to account for designed-in future benefits, this is outlined in Chapter 4 and forms the
foundation for the rest of the work. A number of feasibility studies are conducted based on
this methodology, exploring the benefits of design for deconstruction for three different
structural bay types. These studies are debated in Chapter 5. A tool, Sakura, was developed to
allow designers to explore the benefits of design for deconstruction within their own projects;
this is described in Chapter 6. Sakura was utilised to calculate the energy and carbon savings
from designing for deconstruction for a number of different case studies projects. These
included a range of building types and materials. The case studies and results are examined in
Chapter 7. Chapter 8 ties the work together, discussing the sustainability of design for
deconstruction and debates how uptake of the strategy might be increased. Finally conclusions
and recommendations for further work are presented in Chapter 9.
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2 Literature Review
2.1 Introduction
This chapter builds upon the background set out in the introduction chapter where
environmental concerns were set out and the idea of deconstruction was introduced. In this
chapter, current literature on the topics of deconstruction, design for deconstruction and
material reuse is reviewed. Different structural materials are considered for their suitability in
deconstruction. The concept and role of environmental assessment methods are discussed and
the implications these could have for design for deconstruction and material reuse are
debated. This chapter identifies gaps in existing knowledge and therefore sets the agenda for
the rest of the work within this thesis. Work in this area is fast moving and this literature
review is current at the time of writing on 01/09/12.
The relevance and potential of design for deconstruction was explored in the introduction, the
work presented here focuses more on the practicality and implementation of the approach.
2.2 Software to assess the feasibility and potential economic benefits of
deconstruction
For designers to alter their approach it is important to have firm reasons why deconstruction
might be preferable to demolition. Various different research groups have developed software
to assess the benefits of deconstruction as opposed to demolition. A tool of this kind, to
estimate the cost and revenue potential from deconstruction is outlined by Guy and Ohlsen
(2003) as part of the CIB 287 publication. This software was developed with the intention that
it could be used to assess which existing buildings were most suitable for deconstruction as
well as being an educational tool about deconstruction. It is also hoped that it could be used at
the design stage of new structures to help maximise the incorporation of salvageable
materials. Details of the current (or future) building are input into the software which assesses
these details on their suitability for deconstruction and gives detailed output on the potential
value of the salvageable materials including estimates for the labour time and therefore costs
to deconstruct. The software can potentially be used to enable deconstruction contractors to
give a more competitive bid for the removal of a building, thus hopefully enabling more
buildings to be deconstructed rather than demolished.
Another piece of software is the deconstruction material estimation tool (DEMT) developed at
the National Defence Centre for Environmental Excellence (NDCEE). This tool is intended to be
used to reduce construction and demolition waste within the Department of Defence, in the
USA. It is essentially a spreadsheet, where the user inputs details about the existing building
and the spreadsheet estimates the feasibility of deconstruction and the potential quantities of
materials to be salvaged. It also estimates the labour hours that will be required, the potential
cost, and the potential revenue from the salvaged materials (NDCEE, 2005).
The Building Research Establishment (BRE) has developed software that minimises waste from
demolition and encourages deconstruction. SMARTWasteTM is an analysis tool designed to help
reduce waste generation; it can also be used to provide pre-demolition audits, which assess
the materials/components within the building looking at their suitability for reuse or recycling
and therefore determining whether it is worth deconstructing the building for maximum
material recovery (Hobbs & Hurley, 2001). As part of later work, BRE looked at six case studies
(covering various building types), carrying out pre-demolition audits, reclamation valuation
surveys and an environmental quantification of structure and contents. SMARTWasteTM was
used as part of this analysis; the material type of potential waste output is tabulated, showing
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large amounts of concrete waste in most building types (hospitals being the exception). A
further table shows the potential for reuse, recycling or where landfill is the only option. Large
percentages of the materials recovered could be reused or recycled, with pre-fabricated
housing showing particularly high reuse values (Hurley, 2003). However, unless this type of
analysis is carried out, the true potential of the materials within existing buildings is unlikely to
be fully recognised, resulting in large amounts of waste unnecessarily going to landfill. Hurley
(2003) suggests that a pre-demolition audit and associated analysis should be included within
tender documents for demolition/deconstruction projects. This would however be dependent
on the client being conscious of the need for this type of analysis. Perhaps demolition
contractors should be made more aware of the potential economic benefits of material
recovery, so that pre-demolition audits become an integrated part of the demolition work.
Another piece of software, aimed more at being deployed at the design stage to optimise
building’s end of life potential is BELCANTO – Building End of Life ANalysis Tool (Dorsthorst, &
Kowalczyk, 2002)). This tool was being developed to help analyse which end of life approach is
best suited to a particular building, as described in Dorsthort & Kowalczyk’s paper ‘Design for
Recycling’. The software will help target whether reuse of the construction (DFA), reuse of the
elements (DFDc) or recycling of the materials (DFDm) is the most appropriate end of life
scenario. The idea was that a designer can use BELCANTO to help optimise their building
design in terms of end of life considerations. Once materials choices and other associated
decisions have been input into the program, BELCANTO will give the environmental load and
life cycle costs for these choices and therefore give the most appropriate end of life scenario.
However, it does not seem that further developments have been made on this program since
the Dorsthorst & Kowalczyk’s paper in 2002, or it may be that the tool has been given a
different name, so cannot be identified as the same tool.
2.3 Deconstruction feasibility of specific construction materials
There are a number of different construction techniques, and deconstruction will be more
appropriate for some of these compared to others. This part of the thesis will look at timber,
masonry, concrete and steel as the major construction techniques and assess the suitability of
deconstruction for existing buildings built in these ways.
2.3.1 Timber
Deconstruction of timber buildings on a domestic scale is quite common in many countries.
Much of the recovered timber is also reused – although there can be problems with re-
certifying structural timber, so it is not always reused for a structural purpose. It is generally
thought that larger timber components are easier to salvage, as they can be deconstructed
with minimal damage to them (Webster & Costello, 2005). Crowther (2003) states that older
timber structures (those about 70 -100 years old) are often ideal for deconstruction as they
use simple construction techniques, and the timber is generally in standard sizes, making it
ideal for recovery and reuse. It is suggested that on projects of this kind an eighty percent
recovery rate can be achieved, with these materials recycled or reused, depending on their
condition. The type of timber originally used may also dictate whether it is economical to
deconstruct. In the USA, higher values are placed on rarer species, softwoods such as Douglas
Fir, Southern Yellow Pine, Cedar and some hardwoods (Neun & Grothe, 2001), and so buildings
containing these are more likely to be deconstructed for maximum salvage.
A major factor in the deconstruction of timber structures is the type of jointing that has been
used. The use of bolts or metal plate connectors are ideal for deconstruction as these can
normally be easily removed with minimal damage to the timber, allowing for maximum
material recovery and reuse. Screws, nails, staples and adhesives in joints should be avoided as
they make deconstruction difficult and limit future reuse. In the cases where the timber
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cannot be reused in its current form, it can normally be recycled. However, in some cases
where the timber is damaged or weathered it can be reprocessed before reuse, but it is not
always economical to do. If large amounts of low quality or smaller sections of timber are
recovered then these could be laminated together to produced longer, more usable lengths of
timber (Grantham, 2002).
One of the biggest problems with deconstructing existing timber structures is that recovery
rates can be significantly reduced if damp has penetrated the building envelope. Damp can
cause serious lasting damage to the timber components, rendering them unsuitable for reuse
(Guy, B. et al. Unknown date). Insect infestations can also be a problem. In a study of
deconstruction in different US cities it was found that much of the timber in Miami was
unsuitable for reuse due to termite damage (Neun & Grothe, 2001). Both of these issues
demonstrate the importance of assessing the state of the building before deciding whether to
deconstruct or not.
2.3.2 Masonry
Masonry encompasses brick construction, stone and block buildings. Bricks and blocks are
generally made in standard sizes, which makes them convenient to reuse, however a major
factor in the recovery of these types of components is how they are fixed together.
Traditionally, bricks were joined using lime mortar, this was weaker than the bricks, so the
bricks could be easily separated, cleaned and then reused – as is often the case when projects
use traditional bricks to match with existing buildings, there is a large market for traditional
bricks. However, in newer constructions cement mortar is used, this is stronger than the
bricks, which means it is difficult to separate the bricks without breaking them – often the only
reuse for bricks fixed in this way is to crush them and reuse them as a road base or as fill
material. In brick and block construction the wall ties can also cause further damage to the
bricks; however the wall ties can be recycled after use (Garrod, 2002). Traditionally built stone
buildings can often be deconstructed as these either use no mortar or lime mortar, the stone
can then be recovered and reused – it is considered a valuable material. Even if cement
mortars are used it is sometimes possible to recover at least pieces of stone if large pieces
were used in the first place. Blocks are generally jointed using cement mortars which makes
recovery very difficult, they are generally crushed and recycled (Garrod, 2002).
2.3.3 Concrete
Reinforced concrete structures are generally not suitable for deconstruction, particularly those
that are cast in-situ. These structures are fundamentally difficult to take apart without
damaging the components, therefore reuse is generally not possible, there have however been
some cases with pre-cast elements where it has been possible to deconstruct the building and
then reuse the components. Nonetheless in most cases the best scenario for reinforced
concrete buildings is to separate the reinforcement steel from the concrete so that this can be
recycled and then the concrete is often crushed and used as a road bed (Futaki,
Deconstruction in Japan, 2003, p.6), developments also suggest that the crushed concrete can
be reused as aggregate in the production of new concrete (Elske Linb et al., 2003). It is
important that the concrete has not been contaminated; for example if polystyrene boards are
used within the concrete structure to create voids or forms, it is difficult to separate these out
from the concrete, and therefore it is can be very challenging to reuse the concrete, which
potentially results in large amounts of material being sent to landfill (Fletcher, 2001).
Whilst concrete structures are generally not suitable for reuse, other concrete products like
paving slabs and roof tiles can be reused (Goodier, 2002, p.156). Goodier, (2002) also states
that some concrete flooring systems could be reused depending on the type of jointing, those
joined in-situ are unlikely to be suitable for reuse. However, the biggest barrier for the
deconstruction of concrete structures is economic – there is often no or minimal economic
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gain for reusing concrete products (Goodier, 2002) and while this is the case it will be difficult
to make the case for the reuse of concrete products. There are also a number of physical
barriers for the deconstruction of existing concrete buildings: elements that have been
pre/post tensioned are dangerous to de-stress, joints between units or elements are generally
mortared, glued or tied with reinforcement which makes them difficult to separate.
There are, however, a few cases where reinforced concrete buildings have been deconstructed
and the elements reused. In Middelburg in the Netherlands, the top seven floors of an
apartment building were deconstructed and then reused to build two new, smaller apartment
blocks. Deconstruction was possible due to the dry mounting jointing methods used (either
steel strips or bolted connections) between all the concrete elements except the floor. The
floor to floor joints were grouted but these could be cut through once the wall elements above
were lifted. Once the elements were removed some repair work was carried out on them
before they were used in the construction of the new apartment buildings (Dorsthorst &
Kowalczyk, 2003, pp.8-10).
2.3.4 Steel
Few existing steel buildings seem to have been deconstructed, this may because steel
construction is a newer technique and therefore the majority of buildings that have been built
in this manner have not yet reached the end of their useable life and so have not been
deconstructed. The lack of deconstruction of steel buildings may also be due to the ease of
separating steel from other construction materials and then recycling it. If the main aim is to
recycle the steel then consideration does not need to be given to not damaging the steel
elements – so the steel structure can be cut out and then taken apart using a hydraulic
compressive smash machine (Futaki, 2003, p.7). Indeed recycling steel is such a standard
procedure that according to Futaki (2003) deconstruction for reuse is not considered in Japan.
However, reuse of steel elements does occur with thirteen percent of structural steel sections
being recycled, compared to the eighty-six percent that are recycled (Dowling, 2010). It is
hoped that this reuse number can increase, according to Burgan and Sansom, ‘the potential for
re-use of steel components has been enhanced by the standardization of components and
connections’ (2006, p.1182).
If existing steel buildings are to be deconstructed with reuse of elements as an aim, then the
connection types between elements becomes important. Bolted connections are easiest to
take apart without damage to the steel. Where steel is used in composite construction with
concrete, deconstruction can be difficult – as it can be very challenging to separate the steel
from the concrete without damaging it. Contamination from fire protection can also be a
problem in the reuse of steel structural components, where fire protection is sprayed onto the
elements, removal of this can be uneconomical, particularly when potentially hazardous
materials have been used (Lennon, 2002). Fletcher (2001) states that the use of intumescent
paint or cementitious slurry as fire protection methods are not only difficult to remove from
the steel but also add to the environmental impact of the reused steel. He goes on further to
say that encasing steel in fire resistant materials is more suitable if reuse of the steel is desired,
as the encasing materials can be easily removed and the steel then deconstructed and reused.
There are, however, some examples of existing steel structures that have been deconstructed
and the component parts reused. In 1979, after a peace agreement between Egypt and Israel,
all the army camps in the Sinai Peninsula had to be relocated. Within the camps were a series
of permanent steel structures, these were deconstructed and the majority of the components
taken to new sites and reused in the construction of similar structures (Katz, 2003, p.2).
According to Katz (2003), a standard procedure was followed: an initial survey was carried out
to assess which structures would be suitable for deconstruction and reuse, then a detailed
program for deconstruction was outlined, as well as the formulation of a list of items that
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could be reused. Then the deconstruction was carried out, the components relocated, and
finally construction reusing the elements was carried out.
The 2012 London Olympic stadium is a prime example of a current structure that has been
designed for deconstruction. The upper tier of the Stadium was designed to be demountable
(Figure 2.1), so that after the games are completed, it can be down-scaled to a 25,000 seat
stadium for athletics and other sports. This capacity change was considered a key challenge of
the design (UKGBC, 2012b) and is important to the legacy aims of the games (Brown, J. 2012).
Figure 2.1: 2012 Olympic Stadium, top tier designed for deconstruction (UKGBC, 2012b)
Not only is the upper tier designed for deconstruction but the roof trusses contain reused steel
elements, the roof design was adapted to incorporate these (UKGBC, 2012). It is assumed that
the steel would be reused after deconstruction, but an NSC article states that ‘the majority of
London’s steelwork is demountable and can be recycled at a later date’ (Cooper, 2009, p.16).
Whilst it is important that the upper tier can be easily removed – to provide a more flexible
stadium, the valuable resource of (what it is assumed will be) predominately undamaged
tubular steelwork should also be recognised. These elements could be reused in another
project – thus dramatically reducing the embodied energy of the new structure – a truly
sustainable use for London’s Olympic Stadium’s (Figure 2.1) unwanted steelwork.
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Figure 2.2: 2012 London Olympic Stadium (UKGBC, 2012b)
Another newly built project that has been built for deconstruction is Vulcan House (Figure 2.3)
in Sheffield. Designed as offices for the UK border agency, it is made up of two buildings, both
of which achieved BREEAM excellent ratings. The buildings incorporate a series of strategies to
make them environmentally efficient, as well as user friendly. Both buildings use steel frame
construction, with approximately 980 tonnes of structural steelwork being used (Corus, 2008).
An important aspect of the design that is not mentioned in the Corus document, but is
commented on in the OGC (Office of Government Commerce) case study is that the frame is
designed to be deconstructable. ‘In its design and construction the potential future removal of
Vulcan House has been considered through use of a bolted demountable steel frame the
material of which is recyclable’ (OGC, 2009, p.1). As with the Olympic stadium, the full
potential of design for deconstruction does not seem to have been realised – that it allows for
the reuse of steel sections, as a demountable structure allows the individual sections to be
separated with minimal damage, making them ideal for reuse.
Figure 2.3: Vulcan House, Sheffield (Photo credit, David Millington)
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2.4 Design for deconstruction in general terms – basic tactics to be
applied
Having looked at the deconstruction of existing buildings it can be seen that deconstruction of
most structures would be much easier if it had been considered at the design stage and
therefore inherently designed into the building. This tactic towards design is often known as
DfD for short, and is considered in product design as well as building design as a way to
maximise the separation of materials at the end of life, the materials can then be easily
recycled or ideally reused in their current form. A number of papers examine possible design
strategies for DfD, the subsequent sections outline the key points from these.
According to the report ‘Design for Deconstruction’ (Guy, B. et al. Unknown date) there are a
number of basic steps that can be implemented at the design stage that facilitate
deconstruction. Maximising the simplicity and clarity of the construction and the design is the
first step. The next consideration is to minimise the number of different materials used on the
project, this should minimise the different types of connections required. Using mechanical
connections as opposed to chemical ones will enable components to be separated more easily;
the connections should also be simplified wherever possible. Silverstein states that ‘as an
overriding principle, the best connection design strategies preserve the independence of the
members, enhancing both deconstructability and reusability’ (2009, p.28). The use of
hazardous materials should be avoided if at all possible, and if they are used, their position
should be recorded so that they can be easily found when it is time to deconstruct. The use of
composite materials that cannot be reused or recycled should also be avoided. Generally when
material decisions are made, consideration should be given to whether the intention is to
reuse the material in its current form, if the material is durable enough for this, or if the
material is not to be reused, it should be easily recycled. The building should ideally be
designed in layers, so for example that the services are not tangled up with the structure.
According to the SEDA report on Design for Deconstruction (2005), building in layers also
allows for consideration of different life spans of materials, and therefore considers the
importance of access to these individual layers so items such as cladding can be replaced
without disturbing any of the other layers. The layers described within the SEDA report (2005)
are as follows: site, structure, skin, services, space plan and finally ‘stuff’; with the ‘stuff’ being
most frequently altered and the structure considered the most permanent of the layers. The
SEDA report (2005) also states that the building components should be designed to be as
independent as possible – so that individual sections can be replaced with ease and minimal
propping. There are a number of other papers which also present strategies to best design for
deconstruction, these are: Addis & Schouten, 2004; Chini & Balachandram, 2002; Crowther,
2001; Guy & Ciarimboli, unknown date; and Webster & Costello, 2005. The main strategies
from these papers are summarised in table 1.
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Table 2.1: Summary of strategies to be employed when designing for deconstruction
References:
A&S: Addis & Schouten, 2004.
C&B: Chini & Balachandram, 2002.
G&C: Guy & Ciarimboli, unknown date.
M&S: Morgan & Stevenson, (SEDA Guide), 2005.
PC: Crowther, P. 2001
W&C: Webster & Costello, 2005.
2.5 Other Systems Developed to Promote the Reuse of Materials
GAIA architects in Norway developed a building system called ‘Building System for Reuse’
which was based on three main ideas: build in separate layers, components within each layer
should be able to be easily dismantled and replaced, and finally use predominately mono-
materials (avoid the use of composite materials). This system was made up of eighty-eight
timber and concrete components that were specially designed for use in combination with
standard components to produce a series of different constructions that can