Retrofit & Replicate - Hyde Housing Association

More documents

Recommendations

Info

Retrofit & Replicate Project Briefing Project Background: Whilst the environmental focus of the house-building industry has been on new build and the Code for Sustainable Homes, improving the energy efficiency of the nation’s existing housing stock presents a far more important challenge in terms of helping to combat climate change. Our existing stock is typically very inefficient compared to new build housing in terms of energy use, yet less than 20% of existing homes are likely be replaced by 2050. ECD Architects have a long-standing interest in this issue and a track record in exemplar refurbishment in the residential sector. Similarly, Hyde Housing Association have strong policies on sustainability and, with responsibility for over 40,000 dwellings mainly around the south and south-east of England, they were also very interested in the potential of low-carbon refurbishment. ECD approached Hyde late in 2007 with a proposal to undertake an exemplar retrofit project and in January 2008 they identified a suitable void property - a 3-bedroom mid-terrace house in Mottingham, south-east London, typical of their stock. Most analysis of retrofit focuses on targets for reducing carbon emissions - the Government’s Energy White Paper (2007) officially stated the UK’s target to reduce its net carbon emissions by 60% by 2050, which will become a legal obligation once the Climate Change Bill is passed (currently due late 2008). The Review of Sustainability of Existing Homes, produced by the Department for Communities & Local Government in November 2006, declared that the country’s existing housing should fall in line with this target. However, the Existing Homes Alliance and others argue for greater targets – the EHA Declaration states “deep cuts of at least 80% in carbon emissions are needed by 2050, with major progress by 2020”. Recent proposals suggest that the Government is likely to adopt this higher target. The EHA Declaration goes further to propose the approach that must be taken with regard to our existing dwelling stock - “Government and industry action should focus on developing a ‘whole house’ approach which applies packages of low carbon improvements, rather than individual measures, using existing, proven energy efficiency and microgeneration technology. Improvements to water and other resource use efficiency must be included. A whole-house approach brings greater economic savings to business and causes less disruption to households over time.” Retrofit initiatives to date have indeed focussed primarily on installing individual renewables or other lowcarbon technologies. Hyde and ECD therefore agreed that the aim of this project would be to establish the most effective overall package of retrofit measures necessary to achieve the 80% reduction in CO 2 emissions at the Mottingham house and to monitor the performance of the low-carbon improvements in use. In addition, it will record the impact of the retrofit on the incoming tenants over a 24 month period and, at the end of that time, develop a full cost/benefit analysis, with a view to ascertaining the optimum expenditure. This will enable Hyde and others to make the more efficient and effective choices about how best to apply energy saving as part of large scale retrofit programmes. This project will therefore be of huge benefit both in terms of the developing national policy and of helping to frame the approach of individuals and organisations to retrofit. - 1 -
Design Team: ECD Architects are lead designer for the project and are drawing on their sister company, Keegans, to provide extensive cost consultancy and CDM co-ordinator services. Further consultancy input has been forthcoming from Parity Projects, with particular responsibility for the data monitoring aspects of the project. In addition to this quantitative feedback on energy and water use, another of ECD’s sister companies, PPCR, will undertake post-occupancy evaluation interviews with the incoming tenant providing valuable information on comfort and satisfaction. Following interviews and competitive submissions, Mears Ltd were selected as main Contractor partner and began working with ECD to develop the specification. Mears, in turn, introduced Travis Perkins and Kingspan as supply chain and technical partners respectively. We are working to a total capital budget of £80k (including VAT and fees) funded in the main from Hyde internal resources but with all partners and product contributors investing significant resources in the project. A full list of supply partners and their involvement has been included at the end of this document. The Existing Property: 225 Court Farm Road is thought to have been originally constructed in the late 1930’s as part of a large estate development. The external walls are of cavity wall facing brick construction and the original dwelling included suspended timber floors and pitched tiled roofs but no bathroom! Later improvements saw the inclusion of a first floor shower room, the replacement of open fires with a central heating system of gas combination boiler with radiators and the addition of a single-storey rear extension comprising a third bedroom and ensuite bathroom. Fabric improvements over time have seen the addition of double glazing (though of poor quality) and 100mm loft insulation to the pitched roof, though the flat roofed extension included only 25mm mineral wool insulation. A solid concrete floor replaced the timber in the kitchen and the strip out works found that the original water supply was via lead piping and an asbestos tank, with no stopcock found on the premises. Further asbestos was found in the soffit boards. Initial design proposals investigated the potential for a loft conversion at the property but this was eventually ruled out due to a lack of headroom. There is an imperative to enlarge the first floor shower room and further space is required for hot water storage and electrical equipment (inverters, dataloggers etc). SAP assessments were carried out by ECD Project Services for the property, which was found to have a rating of 60, well above the national average of 48 and therefore presenting a significant challenge to achieve the 80% reductions. In March 2008, ECD assigned Heathrow Commissioning to undertake a ‘before’ airtightness test. The purpose of this test was to provide a ‘base case’ with which to compare the completed scheme and to highlight existing leakage points that need mitigation. The results were surprising – 9.16 m3/hr/m2 @ 50 pascals, which is better than current building regulation requirements. The windows were the source of the worst infiltration with poor seals leaking air badly, followed by incoming services penetrations and the loft access hatch. According to PHPP software, specific primary energy use (heating, DHW + auxilliary electricity) at the existing property is estimated to have been 414 kWh/m2/yr with CO 2 emissions rated at 100 kg/m2/yr and space heating demand rated at 223 kWh/m2/yr. - 2 -
Page 1: Retrofit & Replicate Mottingham, So
Page 5 and 6: With these measures in place, the s
Page 7: Materials specifications generally

Retrofit & Replicate - Hyde Housing Association

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?