Heritage Retrofit

14 BCD SPECIAL REPORT ON HERITAGE RETROFIT FIRST ANNUAL EDITION SUSTAINABILITY STANDARDS & REGULATIONS JOHN EDWARDS T HE MENTION of the energy efficiency of buildings almost always brings up U-values, energy performance certificates, standard assessment procedures (SAP and RdSAP) and building regulations. Those who are a little more informed may also refer to terms like BREEAM, Passivhaus, BREDEM and possibly even EnerPhit. These are all to do with prescribed ways of dealing with energy efficiency of buildings and sometimes their wider sustainability. All have their place but will not necessarily be appropriate and reliable, particularly where historic or traditionally constructed buildings are concerned. However, they are often the means by which we have to assess such issues. Many of the acronyms stand for things we don’t necessarily have to adopt, but we do have to be mindful of them because of the potential benefits as well as the potential risks in adopting such schemes and processes. One regulatory framework that applies to almost all development is the Building Regulations, and the part concerning the conservation of fuel and power is particularly important. Although there is some variation between those adopted by each of the UK home nations, all versions require what we call ‘consequential improvements’ when works to the thermal envelope are undertaken. THE BUILDING REGULATIONS In England and Wales, the Building Regulations are worded more emphatically than in Scotland and Northern Ireland. While there is an expectation that reasonable efforts will be made to improve energy efficiency, listed buildings, scheduled monuments and buildings in conservation areas do enjoy some degree of exemption depending on which UK home nation they are in. However, over 90 per cent of traditional buildings don’t come under these categories even though from a technical perspective, most of the buildings are just the same as those which receive statutory protection. In England and Wales ‘special consideration’ can be given to buildings which have vapour permeable construction when the regulations would otherwise require work which may impede the movement of moisture. In Northern Ireland and Scotland it is less emphatic but, as in England and Wales, work must be ‘technically feasible’ and this is where the imposition of such works can be challenged. Here, British Standard 7913 can be used to support the case for not undertaking works which would adversely affect the building’s performance. BS 7913: 2013 Guide to the Conservation of Historic Buildings (to give the standard its full name) emphasises that damp building fabric could be over a third less thermally efficient than dry building fabric, thus highlighting the importance of appropriate repair and maintenance measures as described in the document. In this respect, building maintenance is an energy conservation measure that should always come before the ‘improvements’ arising out of the Building Regulations, RdSAP and such like.. One very important issue that BS 7913 raises is the need for proper condition surveys based on an understanding of the pathology of historic buildings and the materials used: this is especially essential when considering the impact of problems such as damp. Another important issue is the need to consider significance and the undertaking of heritage impact assessments. All traditional buildings have some significance and the impact of measures on that significance always needs to be understood. A miner's cottage in David Street, Cwmdare: analysis of the building's pathology as required under BS 7913: 2013 provided information on the effects of damp on the in situ U-value, and demonstrated that the walls were more thermally efficient than predicted. (Photos: John Edwards)