Vapour barrier is a layer of material with very low water vapour permeability, the purpose of which is to limit the migration of moisture from inside the building into the structural and insulating layers. It is used on the side of heated rooms to prevent condensation in the partitions. Condensation leads to a reduction in thermal insulation, the development of mould and the degradation of timber components.
A vapour barrier can have in the form of a film, membrane or spray-applied coating. Its effectiveness depends largely on the continuity of the laying, the tightness of the joints and the correct integration with the other layers of the envelope.
In prefabricated buildings, this layer is precisely assembled at the panel production stage. This reduces the risk of leaks and ensures that the performance of the envelope is stable over the long term. The correct design and construction of the vapour barrier is a key element in ensuring the durability and energy efficiency of the entire building.
