Building Conservation or Carbon Reduction – What are the Choices?
On 22nd June VICTERI organised an informal debate on the subject of Building Conservation or Carbon Reduction – Constructive Solutions ? Held at the Drayton Arms pub in Arsenal, London the debate brought together experts and practitioners from English Heritage, Camden Council and several architectural practices in a lively discussion. Strong views were put forward on how to transform the energy efficiency of the existing building stock with English Heritage advocating the need to take more time to understand properly how Victorian and Edwardian houses lose heat before making changes, while other speakers emphasised the need to take early and comprehensive action, establishing viable models for highly-insulated building envelopes.
Chairing the discussion was Robin Nicholson, a partner at Edward Cullinan Architects and CABE Commissioner. Robin, who has recently installed Photo-Voltaics on his listed house, pointed out that to reach the government target of an 80% reduction in CO2 by 2050 we needed to carry out one refurb a minute between now and
that year. 80% of the housing stock we will have in 2050 already exists, so action is urgent.
English Heritage Viewpoint
Jarrod Hill, an energy efficiency expert and architect at English Heritage, argued that we need understanding before action in our approach to refurbishing old buildings as we do not know enough about historic materials and how and what rate they lose heat. Moisture retention and breathability of materials are not sufficiently taken into account when evaluating their performance. We should be looking to our overall lifestyle in reducing our carbon impact, consuming less, conserving more and opting for durability. EH
s research on historic buildings, part of a 5-year programme, is measuring their energy efficiency and is likely to establish that they are already sustainable, certainly far more so than many 1960’s and 1970’s buildingsdemolition or even radical change could not be contemplated.
PRP’s Retrofit for The Future Project
Anthony Briden of PRP Architects spoke next, and described PRP’s Retrofit for the Future project, funded by the Technology Strategy Board, which is aiming for carbon emissions of 17 kg per sq m/ year, an average 80% reduction. It will receive, assuming it gets through all procedures, a £130k grant and aims to try out new materials, undergoing 2 years of post-completion monitoring. All work at this terrace house will be undertaken with tenants in situ. Measures planned include 350 mm of loft insulation to achieve a U-value of 0.12 and internal front wall insulation (because the house is in a conservation area) consisting of 50 mm of Spacetherm achieving a U-value of 0.23. This material cost £100 per sq m. Front windows will be replaced with new double-glazed sashes made from 6 mm Pilkington Spacia vacuum glazing. Lighting will be LED, lasting for 80,000 hours, while radiators will be replaced by underfloor heating. Anthony emphasised the need for urgent action in upgrading our pre-1919 housing stock – we cannot afford to wait years before adopting radical approaches.
Conservation in Camden
Joanna Ecclestone, Head of Building Conservation at Camden Council emphasised that she was not an expert in the refurbishment of historic buildings. She is keen that we consume less and conserve more, seeking the re-use of historic assets, which have a high economic value. Research from Historic Scotland has shown that the embodied energy in a tenement building is equal to 1000 years of energy in use. We need to secure behavioural change from energy users in the face of unprecedented energy use.
Camden’s Sustainable Refurb
Chit Chong, Energy and Sustainability Manager for Camden Housing Department, advocated the lessons that he had learned from Camden’s 17 St Augustine Rd refurbishment. He believed that an undue emphasis on patrimony is unhelpful, and not what our children will want from our built heritage. The ‘heritage’ approach will result in a 30 to 50% reduction in CO2 at most, while an 80% reduction is required. In his view Victorian houses are some of the most inefficient houses on the planet; the amount of coal needed to heat them when originally built outweighed their embodied energy within only one or two years. There can be no exceptions, in his view, to the drive to achieve an 80% reduction, while each refurb should be designed to last 100 to 200 years.
Robert Cohen thought that the challenges posed by Climate Change took primacy over anything else; there will be no silver bullets in 20 years time, so we had to act now.
Jarrod Hill re-iterated that, and EH is not simply against change, and its role is a pro-active one. Historic buildings are an asset, and we need to take the time to research more challenging solutions to their refurbishment.
Antony Briden responded that external wall insulation is not technically risky, and Chit Chong thought that the Victorians would have used double-glazing if they had known about it. We should insulate before carrying out other measures and not try and apply inapplicable rules
Joanna Ecclestone thought that many Building Conservation departments were now exploring energy-efficiency measures for historic buildings; Camden have recently authorised solar thermal and PV installations for Victorian houses, and they have also approved retrofitted double glazing for listed Georgian houses