Adding Insulation to Existing Buildings

Insulating the walls is the highest-impact fabric measure on most existing buildings, walls being the single largest heat-loss path, and it is also the one most likely to cause problems if done badly. There are two routes for solid walls, internal and external, plus the much cheaper option of filling a suitable cavity. Choosing between them, and handling the moisture risk each carries, is what separates a transformative retrofit from an expensive one that grows mould. This lesson covers all three and the condensation question that governs them.