Heat and Moisture Regimes in the Facade Thermal Insulation Composite System with Polystyrene Insulation

Facade thermal insulation composite systems with polystyrene insulation are extremely popular in modern construction sphere. Polystyrene and expanded polystyrene insulation plates have increasingly higher level of thermal resistance than classical insulation materials. It has to be stated that the vapour permeability coefficient of polystyrene is ten times less than the vapour permeability coefficient of mineral wool. Thus, the moisture regime process of enclosing structures which contain polystyrene as an insulation layer is significantly more complex than the moisture regime of enclosing structures with mineral wool. The plane of the moisture maximum was calculated using created computer program. The result showed that the moisture maximum was inside insulation layer. It is certain that in terms of providing evidence of this result, it is necessary to calculate the moisture behaviour inside researched facade thermal insulation composite system with polystyrene insulation by an unsteady-state moisture regime mathematical model. The mathematical model based on the moisture potential theory was chosen for assessing unsteady-state moisture behaviour. The second computer program, which solves the moisture transfer equation by finite-different method, was developed. It was shown that the plane of the moisture maximum has the same position according to both used methods. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.