The durability of surface layers of enclosures (outside walls of buildings) is highly influenced by stresses occurring in the plane of contact between finishing materials and that of the enclosure. Damage to external walls depends on a high moisture content, which in turn depends on high water absorption during driving rains. One example of such damage is damage due to direct water penetration in homogeneous walls. The other negative effects of a high moisture content are impaired heat insulation and accelerated degradation. This article investigates the external layer of walls and the durability of different paints. In case of bi-laminar system “paint film - the wall being painted” two opposite processes take place: the water flow rate from the outside towards the wall, and the water vapor flow rate of the wall to the outside. The optimum selection of paint is necessary. An investigation of the durability of wall surface paints in a climatic chamber is instructive only after intermediate investigations and measurements of the substrates’ physical and mechanical properties that aid in predetermining durability. The influence of moisture deformations upon degradation of coatings depends on the porosity of surface materials being coated, and on the origin and macrostructure of the coating.