Unintended Consequences of Internal Wall Insulation ; Increased Risk of Mould Growth for Uninsulated Neighbours

Internal Wall Insulation (IWI) retrofits reduce heat loss from homes, increase comfort and reduce fuel bills, however, they can result in unintended consequences. This paper uses thermal modelling to show that if only one side of a party wall is fitted with IWI, the surface temperature of the uninsulated side will reduce, and its risk of mould growth and surface condensation increases. This has potential implications for works under the Party Wall etc. Act 1996 that is applicable in England and Wales, and the room by room approaches to IWI retrofits.