Linear thermal bridge is the location in a building envelope where increased heat loss occurs along a particular line. It occurs where different structural elements join or the continuity of thermal insulation is altered.
Linear bridges most often occur where the walls meet the ceiling, balcony, foundation or window reveal. In such areas, the heat flow is greater than in the rest of the partition.
Thermal bridges can result in localised cooling of the partition surface which favours the formation of condensation and the growth of mould and mildew. This phenomenon can also lead to increased energy consumption for heating the building. Linear thermal bridges are taken into account in the energy calculation of a building. Their influence is described by the linear heat transfer coefficient, denoted by the symbol Ψ (psi).
