The durability of surface layers of enclosures (outside walls of buildings) is highly influenced by stresses occuring in the plane of contact between finishing materials and that of the enclosure. Variations of sorption moisture in the surface layer of enclosures result in deformations which have to be evaluated together with adsorption and desorption processes in the construction and expressed in specific moisture deformation of construction material. The dependence of the basic building materials of enclosure constructions upon change in material moisture with variation of relative humidity of the air was investigated by way of experiments.