FIELD: building, particularly for arranging membrane or built-up roofing coverings.
SUBSTANCE: method of water-proof mat protection against bulging by provision of vapor-and-air mixture pressure equalizing in covering cavities from both mortar layer sides without breaking air-tightness of water-proof mat involves removing excessive vapor-and-air mixture from cavities between mortar layer and water-proof mat through channels formed in mortar layer. Channels are made as capillaries and pores in mortar layer body by introducing air-permeable filler in mortar mix taken in certain ratio to binding agent to provide mortar layer resistance to air penetration in water saturated condition of 0.2 - 15 m2·hr·Pa/kg and compression resistance of 5 - 10 MPa.
EFFECT: increased functional performance.
