Heritage Retrofit

BCD SPECIAL REPORT ON HERITAGE RETROFIT FIRST ANNUAL EDITION 5 a maximum of 25 years? A particular problem arises with the glass, and this author has yet to be convinced that the building industry is able to resolve the inherently limited lifespan of sealed double- and triple-glazing. Double windows and secondary glazing, which tests have demonstrated to have thermal characteristics at least as good as if not better than sealed glazing units, have been the norm across much of continental Europe for centuries. They often offer a viable alternative that accords with the heritage principle of minimum intervention, is not subject to failure of the glazing technology, and is highly durable. COORDINATED, COST-EFFECTIVE ACTION An increasingly invoked truism is that the most sustainable building is the one that has already been built. Lack of holistic understanding and simplistic energy certification systems serve to undervalue the energy performance of our existing building stock, especially older, traditionally constructed buildings. The retrofitting of our built heritage requires a methodical approach to assessing and respecting its heritage significance in whole and in its discrete parts. Europe’s building stock has a historical and projected longevity that constitutes a major contribution to the reduction of global carbon emissions: through the environmental capital that has already been invested in it; and through the potential for significantly reducing or eliminating the occupancy emissions by a combination of energy efficiency retrofitting and conversion to renewable energy sources. To meet global emissions reduction targets, we need to mainstream retrofit measures and systems to satisfy complementary objectives. Central to this are principles that have hitherto been most closely associated with the heritage sector, including minimum intervention and minimal ecological impact. Common ownership of these across the whole retrofit sector will enable coordinated, cost-effective action at the scale that is required to counter the predicted impacts of anthropological global warming. Further Information EFFESUS Consortium, Energy Efficiency in European Historic Urban Districts: A Practical Guidance , 2016 (http://bc-url.com/effesus ) European Union, Toledo Declaration on Urban Development, 2010 (http://bc-url.com/toledo ) C Hermann and D Rodwell, ‘Heritage Significance Assessments to Evaluate Retrofit Impacts’, in B Szmygin (ed), How to Assess Built Heritage? , Heritage for Future, Florence-Lublin, 2015 (http://bc-url.com/assess) C Hermann and D Rodwell, ‘Retrofit Measures for Historic Buildings and Cities’, in Context 142, 2015 J Hulme and S Doran, In-situ Measurements of Wall U-values in English Housing , BRE, Watford, 2014 (http://bc-url.com/wall-uvalues ) D Rodwell, ‘Climate Change and Energy Initiatives in Scotland’, in Context 115, 2010 J Wallsgrove, ‘The Justice Estate’s Energy Use’, in Context 103, 2008 C Wood, ‘Making Historic Buildings Even More Sustainable’, in Context 111, 2009 World Commission on Environment and Development, Our Common Future (aka The Brundtland Report ), OUP, Oxford, 1987 The World Conservation Union, United Nations Environment Programme and World Wide Fund for Nature, Caring for the Earth: A Strategy for Sustainable Living , 1991 DENNIS RODWELL , architect-planner, is an international consultant in cultural heritage and sustainable urban development (www.dennisrodwell. co.uk ). Previously a principal in private practice and a heritage at risk developer, he has also served in local government posts as architect, conservation officer, urban designer, principal planner and project manager. He was a partner in the EFFESUS research project described in this article. Sibiu, Romania: historic double windows, typical of those found throughout Central and Eastern Europe Stirling Castle, Scotland: crafted secondary glazing and shutters have been installed as part of the restoration works in the royal apartments.