Retrofitting an old house to make it more energy efficient helps cut bills, reduces carbon emissions, and makes it more comfortable. Even so, we first need to consider how the building works to avoid any unintended consequences, such as condensation, mould, poor internal air quality, and decay due to trapped moisture.
Old properties are different from modern buildings. Generally, their walls are solid and constructed using lime mortars, renders, and plaster, which allow the building to breathe so moisture isn’t trapped within their fabric. Using the wrong materials, such as cement-rich mortars, renders, and plasters, traps moisture and may result in rot and untold damage. The same problems occur when incompatible insulation materials are used.
‘Before you do anything, make sure the fabric of the building is sound and you have resolved any pre-existing damp issues,’ warns Gavril Postnikov of Conker Conservation, a practice specialising in sustainable, energyefficient buildings. ‘If you intervene, for example by installing insulation, you could exacerbate existing problems
