C O N T E X T 1 1 5 : J U LY 2 0 1 0 41 calculation models pose a major threat to the domestic component of Scotland’s historic built environment. This can be gauged by the fact that the interventions that are deemed necessary have been estimated to require a capital expenditure of £16 billion between now and 2020.The carbon footprint of these interventions has not been computed. Since 2008, a series of events has been held in Edinburgh hosted by Changeworks ¹, Historic Scotland, the Scottish Parliament and others, all aimed at strengthening understanding of the environmental performance of traditional buildings and presenting the latest research into intervention options. Historic Scotland has recently established a dedicated climate change unit 2, and Edinburgh World Heritage (supported by the Climate Challenge Fund) has appointed an energy efficiency officer 3. One set of research has addressed the potential for installing renewable micro-generation technologies in traditional housing. The general conclusions for urban properties are that – discounting their impact on appearance – wind turbines are not currently cost effective; also, that ground source heat recovery is not viable. The balance of options will clearly vary for rural locations. The testing of solar (heating) and photovoltaic (electricity) panels has proved more positive, and Edinburgh’s historic environment offers multiple opportunities for siting them inconspicuously. Another set of research has focused on interventions to the fabric of traditional buildings. Of these, the aim to install or upgrade loft insulation (to 270mm thickness) in all homes by 2015 may be considered the least contentious, followed by cavity insulation within the same timescale; the latter more applicable to post- rather than pre-1919 houses. Potentially more contentious is the testing being carried out to walls, floors and windows. For walls and floors, Historic Scotland has the advantage of a readymade laboratory in the form of disused service and outbuildings on the Dumfries House estate in Ayrshire. Here, testing on walls is being carried out using breathable infills behind both plasterboard and timber laths, including with cellulose fibre, hemp board and lightweight expanded-clay aggregate; limecrete in the replacement of solid floors; and breathable insulated external renders using hydraulic lime and hemp mixes in replacement of cementitious renders. Priority is being given in this research to locally-sourced natural materials with a reduced carbon footprint. But the disruptive effects are significant and the loss to any surviving interior detailing all but total. For windows, the various research initiatives in Scotland are seeking to address multi-paned, singleglazed traditional windows by a higher level of intervention than is supported south of the border. Here, focusing on the replacement of individual panes with bespoke high performance double glazing, the solutions vary considerably: from the less expensive slim-line patterns made locally, to the most expensive but higher performance versions imported from Japan. Some of these patterns are so slim that they require spacers (which are inevitably visible) to keep the two thicknesses of glass apart.The costs can run to £1,700 a window, and no mention is made of the notoriously limited life cycle of sealed double-glazing. A quarter of Edinburgh’s half million population live in conservation areas. More relevant, in this author’s view, would be greater focus on options for non-reflective secondary glazing, including design options that support the additional benefit of the internal shutters that survive in many of the city’s homes. Historic Scotland reports that the building industry is responding to the need for innovative products to meet the climate change challenge. By addressing the pre-1919 building stock in its entirety, it is seeking to provide templates for the best practice sustainable refurbishment of all traditional buildings in Scotland, with concomitant economies of scale. The backdrop of legislative imperatives and political pressures does not encourage a holistic and measured approach to the issues. Unless and until we have an enhanced information base, there is a serious risk that retro-fitting traditional buildings in order to satisfy limited energy efficiency criteria could be seriously harmful to character in the historic environment; and add to the causes of climate change rather than reduce them. Has the 1987 Brundtland Report’s warning that environmental sustainability must take precedence over economic sustainability, as it underscores the survival of all life forms on our planet, become lost somewhere along the way? References ¹ www.changeworks. org.uk Publications by Changeworks include Energy Heritage: A guide to improving energy efficiency in traditional and historic homes, 2008; and Renewable Heritage: a guide to microgeneration in traditional and historic homes, 2009 2 www.historic-scotland. gov.uk/index/heritage/ climatechange.htm 3 www.ewht.org.uk/ energy-efficiency-andsustainability Dennis Rodwell is a consultant in cultural heritage and sustainable urban development. Individual slim-line sealed double-glazing units fitted into a typical multi-paned window in an Edinburgh tenement: visually unobtrusive, but expensive and with a loss of historic fabric (Photo: Crown Copyright, reproduced by courtesy of Historic Scotland www. historicscotlandimages. gov.uk) The use of sheep’s wool in loft insulation is one of the preferred options for its overall environmental performance. (Photo: Second Nature UK Ltd)
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