Clifford Design have been working with Architect Nicola Westbury to upgrade the thermal performance and also extend her own C17 Grade 2 listed home in Surrey. Nicola is a Society for the Protection of Ancient Buildings scholar who specialises in historic buildings conservation.
Retrofit of historic buildings requires a specialist approach with an understanding of suitability of materials and construction techniques. Repair, maintenance and removal of inappropriate materials is always the starting point, then a light touch retrofit using natural materials so as not to risk damage to either the fabric of the building or its historical significance.
Any works to listed buildings beyond maintenance and like for like repair require listed building consent.
A full property assessment was undertaken including thermal imaging survey combined with an air leakage pressure test as well as a Heritage impact risk assesment. Interestingly in the air leakage test the C17 buildings performance was far higher than standard assumptions and similar to many properties built in the 1990’s. Examining all of the fabric elements allowed more accurate values to be used in a PHPP heat loss model. The PHPP model was then used to test a number of improvement options that were also evaluated for their risk to the building fabric and its historical significance.
