Historic buildings contractor the Cathedral Works Organisation (CWO) has cautioned historic building owners over taking radical energy efficiency measures to cut carbon emissions.
The Chichester-based contractor has warned that property owners seeking to go 'green' are in danger of harming their buildings since certain steps to avoid energy wastage, such as insulation, are not always compatible with heritage structures.
Although the Government is committed to reducing overall carbon emissions by at least 80 per cent by 2050. Meeting this target has resulted in legislation and building regulations steadily increasing the energy efficiency required by existing buildings. The Energy Bill 2011 is currently progressing through the House of Commons, and seeks to widen access to Energy Performance Certificates (EPCs) that rate the efficiency of buildings.
Bernard Burns, managing director of CWO commented: 'It is key that the UK meets its carbon targets by improving its buildings' energy performance. However, historic buildings need to be treated carefully since they weren't constructed to be air tight. Insulating older properties can introduce problems, particularly humidity since historic buildings have their own natural ventilation and were not designed for high levels of heat. Meanwhile, over-heating can lead to cracking in the timber and plasterwork as the moisture is removed, causing long-term damage to the fabric of the building.'
CWO has carried out restoration work on historic buildings from bridges and castles to churches, and suggests that historic building owners also should not underestimate the efficiency of their buildings.
Research from the Society for the Protection of Ancient Buildings (SPAB) on the performance of old buildings suggest that standard U-value calculations, used across the construction industry to rate efficiency, underestimate the thermal performance of traditionally built walls. In its study SPAB measured the heat loss through traditional walls - including limestone, slate and granite - and compared the results with the theoretical values produced by BuildDesk U 3.4 software. The research states that 79 per cent of the traditionally built walls sampled performed as much as three times better then the software predicted.
Mr Burns added: 'In the past theoretical performance figures have been used as a standard base measurement by professionals and building owners to judge thermal efficiency when upgrading or altering historic buildings or even when assessing buildings for EPCs. Following SPAB's heat loss research it is clear professionals and building owners should measure their individual building's energy efficiency since many heritage properties are far more efficient than theoretical performance figures suggest.'
