IWI Thermal Properties and the Risk of Condensation and Mould GrowthImposed upon Neighbors at a Party Wall Junction

Internal wall insulation (IWI) is one of the few retrofit approaches to reduce heat loss through solid brick walls. Discontinuities in the insulation layer can result in thermal bridges, leading to reduced surface temperatures and the potential for condensation to form. Party wall junctions retrofitted with IWI act as discontinuities when neighbouring homes do not have IWI, leading to reduced surface temperatures on the neighbouring side. The condensation risk imposed on the uninsulated neighbour by a range of notional IWI systems are simulated, the resulting temperature factors indicate whether each system imposes a risk upon the uninsulated neighbour. Thicker, higher performing IWI systems were found to result in greater risk in the neighbouring property.