One of major problems of building is to design the construction of structures such as to avoid the occurrence of fluid therein. Depending on the type of construction and used materials the water vapor can pass through a building or trapped therein. The purpose of this article is to add some important characteristics of water vapor permeability of building materials which are reflected incompletely in the regulations. Much attention was given to a series of tests conducted on samples of materials which were produced by firms manufacturers for modern construction: stone walling concrete of the brand SKTS 1R-1, sandstone stone wall of brand KSKTS 40-20-19-50/950, calcined clay brick, tong of brand D600, wood (pine). As a result of research new data of materialsused nowadays in construction of protecting designs are obtained. These data can be applied in thermotechnical calculations of buildings and constructions.