Summary of Key Points
This statement was written in my former capacity as a Research Associate at UCL.
The baseline environmental comparisons are with a hypothetical new development that complies with current building regulations or with current planning regulations. They do not offer any comparison to either the current situation at Aylesbury or a refurbished situation at Aylesbury. This makes these figures largely irrelevant for making a rigorous appraisal of the environmental, social and economic impacts of the proposed redevelopment on the local area.
Many social and economic impacts have not been addressed quantitatively or qualitatively in the publicly available information that refers to refurbishment (1997 to 2005). For example, important impacts reported in the literature include: the physical and mental health impacts on residents of disruption during construction and of temporary displacement or permanent relocation; and the costs of decanting, temporary accommodation and of rehousing residents from the social housing units that will not be replaced.
Of the documents in the public domain – particularly those containing data tables – many are PDFs. This makes it difficult to check data since it cannot be analysed using other software. Some documents are also illegible such that the data or text are not machine-readable. This makes it very difficult for local authorities, communities and the general public to interrogate or share these resources.
- Waste: A pre-demolition waste audit by the Building Research Establishment (2014) does not appear to be available in the public domain.
- Energy: Embodied energy and carbon are not accounted for in evaluation of the Aylesbury Estate now, a refurbished Aylesbury Estate or the proposed redevelopment. Embodied energy and carbon refer to the energy and associated carbon emissions required to extract, process, transport and the dispose of construction materials.
- Water: surface water run-off targets in the planning application are based on the bare minimum, given as 50% of run-off from brownfield rates (Sustainable Design and Construction SPG). The London Plan actually targets greenfield run-off rates, much lower than brownfield rates since surface water is assumed to infiltrate (rather than run-off) sites with green space, so this seems unambitious. There is no account of reduced run-off rates at a refurbished Aylesbury. Embodied water is not accounted for. This is the water needed to produce new materials.
Full Statement
I. INTRODUCTION
1. I am a Research Associate at the Centre for Urban Sustainability and Resilience at University College London (UCL). I am a Chartered Building Services Engineer and LEED A.P. and have a Masters in Engineering (Civils Group) from the University of Cambridge (2000), a specialized masters in civil engineering awarded by Ecole Centrale de Paris (2001) and a PhD awarded by University College London (2009). As a professional engineer, I have worked on the design of housing in the UK and on technical and strategic aspects of post-disaster reconstruction in other countries. I lecture on sustainable infrastructure, risk mitigation and urban flooding and drainage. I have published on building physics and on the use of technical evidence about the built environment in decision-making. I have been in my current role at UCL for two and half years.
2. In my role as a Research Associate at UCL, I took part in a detailed review of the evidence on the environmental and social impacts of refurbishment and demolition of social housing. I led the review of environmental impacts, focusing on the modelling of building performance and life cycle carbon emissions.
3. My statement should be read in conjunction with the report submitted by UCL to the London Assembly’s Housing Committee investigation into Demolition and Refurbishment of London’s Social Housing Estates in 2014.[1] This statement will be in the public domain and seeks to communicate the environmental concerns as clearly as possible.
4. I make this statement to present the current evidence and to highlight the published cases that offer the most informative comparisons to the Aylesbury Estate. This statement is based on data in the public domain and as such does not offer a detailed, specific analysis of the Aylesbury Estate because:
a) there are no available data that rigorously quantify or evaluate social, economic or environmental benefits of different options for this estate;
b) there are no data that quantify social or environmental costs of different options for this estate; and
c) the definition of the term “environment” in the planning documents is vague and only mentioned in the context of unspecified “environmental improvements” or in the context of “environment and community safety”[2];
II. Evidence on environmental and social impacts of refurbishment and demolition
5. In 2014, the London Assembly conducted and investigation into the demolition of social housing in London and UCL submitted written evidence to this investigation. The findings of the London Assembly investigation were published in February 2015[3] and concluded that an effective decision-making process would: “Include in its option appraisal effective consideration of medium- to long-term social and environmental issues. It would incorporate an assessment of the lifecycle carbon impacts of options and feature existing residents’ needs and wishes in terms of their lived experience, in tandem with the wider strategic and financial imperatives.”
6. The research conducted by UCL that was submitted to this investigation focused on:
a) the health and well-being of people living with regeneration projects
b) building performance in terms of energy, water and waste
c) understanding the assumptions underpinning the economic and environmental calculations applied to refurbishment and demolition
7. The research methodology was based on a literature review of peer-reviewed academic articles and edited industry reports. It was conducted by a multi-disciplinary team of researchers and thus synthesized evidence from different fields into a report. It was then reviewed by leading academics and practitioners.
8. In general, the review found that:
a) rather than contradictory or ‘conflicting evidence’[4], most published studies were highly context-specific and patchy in their coverage of different places, groups of people and the impacts that had been assessed;
b) while academic literature is potentially available to the general public, developers and local authorities, it is not always free to download from academic journals or fast to review;
c) other relevant documents and analyses are not always in the public domain and emerging evidence appears or is categorised as anecdotal.
9. In particular, the review exposed a number of difficulties that Local Authorities, Developers and Communities are likely to encounter when commissioning or interrogating a cost benefit analysis or assessing the social, economic and environmental impacts of different options on an area:
a) Embodied energy is rarely accounted for by developers and local authorities but is critical in reducing overall carbon dioxide emissions. There is now some consistency in the estimates for the embodied energy of different building materials in the UK supply chain but this cannot be extrapolated directly to the embodied energy of different buildings. Embodied energy is regularly reported as a percentage of the energy used over the lifetime of a building. If it appears to be a low percentage, it is dismissed. Using these percentages to make general claims about the performance of buildings is spurious: the data vary so widely and depend so much on building types, assumed lifetimes and supply chains that they can rarely be compared and should be examined on a case by case basis;
b) The industry advice given in the ICE Demolition Protocol is to start by considering reuse of buildings before considering reuse of materials after demolition. This would minimise demand for aggregates, minimise construction, excavation and demolition waste (CE&D) and reduce the costs faced by Londoners of building new facilities to deal with CE&D waste, all of which are policies set out in the London Plan.
c) Measures to manage drinking water inside buildings and surface water and flood risks around neighbourhoods can be retrofitted.
d) Modelling any impacts is highly dependent on assumptions about how long buildings are expected to last; future energy prices; good agreement between the models and real building performance; and the behaviour of people living in buildings. These assumptions need to be explicit in any options appraisal or consultation for local authorities, developers and communities to have a shared understanding of the costs and benefits of refurbishment and demolition.
10. These findings show that effective consideration of medium- to long-term social and environmental issues is possible – guidance, case studies and data are available – but that, because weighing up options is so subject to assumptions, making these assumptions explicit and transparent is the basis of understanding impacts and what is thus in the public interest.
II. Implications of this work for the Aylesbury Estate
11. In order to comment on the Aylesbury Estate, a three-pronged approach has been taken. Firstly, this statement summarises an audit of the information available on environmental, social and environmental impacts. Secondly, for the purposes of illustration, this statement shows some of the parameters that would be required to develop an appropriate options appraisal. Thirdly, case studies and references that are relevant to Aylesbury Estate are offered.
12. The information audit, summarised below, has found that:
a) The recent planning application (2015) and other documents available in the public domain present some environmental impacts. These have been presented as percentage changes or improvements (e.g. percentage reductions in carbon emissions). The important issue is the starting point against which these percentages represent an improvement, also known as the baseline. In the planning application the baseline comparisons are with a hypothetical new development that complies with current building regulations or with current planning regulations. They do not offer any comparison to either the current situation at Aylesbury or a refurbished situation at Aylesbury. This makes these figures largely irrelevant for making a rigorous appraisal of the environmental, social and economic impacts of the proposed redevelopment on the local area.
b) Many social and economic impacts have not been addressed quantitatively or qualitatively in the publicly available information that refers to refurbishment (1997 to 2005). For example, important impacts reported in the literature include: the physical and mental health impacts on residents of disruption during construction and of temporary displacement or permanent relocation; and the costs of decanting, temporary accommodation and of rehousing residents from the social housing units that will not be replaced.
c) Of the documents in the public domain – particularly those containing data tables – many are PDFs. This makes it difficult to check data since it cannot be analysed using other software. Some documents are also illegible such that the data or text are not machine-readable. This makes it very difficult for local authorities, communities and the general public to interrogate or share these resources.
d) Waste: A pre-demolition waste audit by the Building Research Establishment (2014) does not appear to be available in the public domain.
e) Energy: Embodied energy and carbon are not accounted for in evaluation of the Aylesbury Estate now, a refurbished Aylesbury Estate or the proposed redevelopment. Embodied energy and carbon refer to the energy and associated carbon emissions required to extract, process, transport and the dispose of construction materials.
f) Water: surface water run-off targets in the planning application are based on the bare minimum, given as 50% of run-off from brownfield rates (Sustainable Design and Construction SPG). The London Plan actually targets greenfield run-off rates, much lower than brownfield rates since surface water is assumed to infiltrate (rather than run-off) sites with green space, so this seems unambitious. There is no account of reduced run-off rates at a refurbished Aylesbury. Embodied water is not accounted for. This is the water needed to produce new materials.
III. Comments on Chapter 5 of the London Plan: London’s Response to Climate Change
13. The sections of the London Plan that are relevant to demolition and refurbishment are in Chapter 5: London’s Response to Climate Change (Chapter 5 of the London Plan). Refurbishment potentially fits within or happens in parallel with “major development proposals”, “new developments” and “developments” making the following policies applicable: overheating and cooling (5.9), urban greening (5.10), green roofs and development site environs (5.11), lood risk management (5.12), sustainable drainage (5.13), water quality and wastewater infrastructure (5.14), water use and supplies (5.15), waste self-sufficiency (5.16).
14. Section 5.7 states that: "The biggest challenge for London is to improve the contribution of the existing building stock (80 per cent of which will be still standing in 2050) to mitigating and adapting to climate change." Although this gives no source for the 80:20 ratio and does not identify which 20% of stock will not be standing, this is the only steer in the plan towards addressing existing stock. Beyond this, the plan refers to retrofitting (5.4, 5.29, 5.3) in reducing energy consumption and carbon emissions (5.11) and refurbishment is relevant to policies covering water, flooding, waste and decentralized energy.
15. In terms of energy, decentralised energy systems, for example, a centralized energy system like the plant room serving the Aylesbury or the Olympic Park’s energy centre, are identified as potential routes to decarbonisation. “Overall, the most substantial emissions savings London can make will come from initiatives to decarbonise its energy supply and to reduce the emissions from the existing building stock”(5.15) thus also avoiding additional embodied emissions and emissions associated with demolition and waste disposal. It does however note that costs and feasibility studies need to be done at an early stage in any proposal (5.8). This potentially includes the feasibility of retaining buildings and infrastructure to avoid embodied emissions and waste to landfill.
16. In terms of waste from demolition and construction, the London Plan referes to the ICE Demolition Protocol. The 2008 guidance requires an appraisal of the reuse of buildings and whether they really need to be demolished while the 2003 version only looks at reuse of materials, assuming demolition is going to happen. The London Plan has no target for minimising waste or increasing reuse of waste. Instead, it aims for levels of recycling and reuse that exceed 95% of waste generated in any given year. New facilities to deal with construction, excavation and demolition waste are encouraged by the Plan (5.18) and, if waste rises, these costs will rise. The Mayor’s policy on ensuring an adequate supply of aggregates (5.20) requires reuse, which, in line with the ICE Demolition Protocol would require the reuse of buildings to be considered in the first instance.
17. In terms of water, all the water efficiency, drainage and flood risk measures mentioned for new developments are possible for refurbishments.
18. Energy Assessments (5.2) require “calculation of the energy demand and carbon dioxide emissions covered by Building Regulations and, separately, the energy demand and carbon dioxide emissions from any other part of the development, including plant or equipment, that are not covered by the Building Regulations (see paragraph 5.22) at each stage of the energy hierarchy” and “reductions should reflect the context of each proposal”. This potentially includes embodied energy and energy associated with transporting or reprocessing waste. Baselines for ‘improvements’ in environmental performance are not given (5.3) but for rigorous analysis would have to included embodied and operational performance and the performance of alternative options including refurbishment. Materials with high embodied energy should be avoided (5.25).
IV. Response to Planning Inspector’s Questions Based on Witness Statement of Catherine Crawford
2nd May 2015
To clarify my responses to the Planning Inspector’s questions about the future, I have given a short additional commentary on the statement I submitted.
- Asbestos Removal at Wilmcote House: the cost of stripping out asbestos was included in Portsmouth City Council’s options appraisal presented in this document: http://www.sustainablehomes.co.uk/hubfs/docs/150304cihbrighton4-ECDKeegans.pdf?t=1429286101903
- Changes to insulation technology in the future: Please refer to Appendix E of my statement, which gives a comparison of the U-values achieved with existing technology at the Wilmcote House as against the current planning regulations. There will be improvements to insulation technology over the next 30 years[i] but my view is that, as the market for retrofitting the built environment grows across Europe, the innovations are likely to be in the delivery and installation mechanisms for retrofitting and that these will bring down the time and cost of works and improve the quality of installation, addressing thermal insulation (U-values) and air tightness.
- Timeframes for refurbishment options: Table 4 of the original UCL literature review on refurbishment and demolition gives the time periods over which various case studies have been modelled. Each model uses different economic and environmental criteria to project costs and benefits. The 120 year projections include the ongoing repair and refurbishment cycles and carbon emissions that would result from both the refurbishment and new build options. The life of any building, new or refurbished, depends on the durability of the materials and their ongoing maintenance regime. The case studies are:
- Clapham Park Regeneration Project, London, 120 year model
- Sandwell Metropolitan Borough Council, West Midlands, 60 year model
- Wilmcote House, Portsmouth, over 30 years
- Borough Grove, Petersfield, Hampshire, 50 years
- Daneville Estate, Liverpool, 30 years
- Clapham Park Regeneration Project, London, 120 year model
[i] This report includes a useful summary of emerging technologies: Thorsell, T. (2012). Advances in Thermal Insulation: Vacuum Insulation Panels and
[1] Demolition or Refurbishment of Social Housing? A review of the evidence, 27th October 2014, http://www.engineering.ucl.ac.uk/engineering-exchange/files/2014/10/Report-Refurbishment-Demolition-Social-Housing.pdf
[2] Southwark Council, Executive Meeting Minutes, Tuesday 27 September 2005,Item 07 - The Aylesbury Estate: Revised Strategy - Report http://moderngov.southwark.gov.uk/CeListDocuments.aspx?CommitteeId=118&MeetingId=986&DF=27%2f09%2f2005&Ver=2
[3] Knock it Down or Do it Up? The challenge of estate regeneration, February 2015 https://www.london.gov.uk/sites/default/files/KnockItDownOrDoItUp_0.pdf
[4] Demolition and Refurbishment of Social Housing Estates in London, https://www.london.gov.uk/sites/default/files/ScopingPaper.pdf