In modern construction the thermal insulation materials are applied at construction practically of any residential unit. They are used for warming of walls, overlappings and roofs. However not all know that in order that the heat-insulation layer reliably protected your house from cold, it is necessary to take care of vapor barrier.
The vapor barrier is the layer of material interfering hit of moisture in the warmed building construction. From where does this moisture undertake?
In the inhabited heated room the water vapor inevitably is formed. It is allocated at breath, washing and drying of linen, in the course of cooking, when using plumbing and sanitary. Pressure of this steam is higher, than atmospheric pressure. Because of this difference of couples influences walls and overlappings of the room, seeking to come to light. At positive temperatures, steam freely gets into warm season through layers of thermal insulation and evaporates.
Otherwise the situation is in the winter, at negative temperature values. In the course of contact of steam with cold wall surface it reaches temperature of "dew point" and accumulates on surface in the form of condensate. As a result, the thermal insulation material and enclosing structures begin to collapse under the influence of moisture. Are formed mold, fungus, walls and overlappings begin to freeze through. To protect buildings from pernicious influence of moisture, establish additional paroizolyatsionny layer. It is recommended to fix for the surfaces adjoining to warm and humid air of premises. As a rule, protect basement overlappings and roofs from steam. Sometimes there is need in installation of paroizolyatsionny layer when warming garret overlappings and walls. For definition of need of mounting of vapor barrier for any given specific case special heattechnical calculation is made. Today there are several types of the materials applied to vapor barrier. Perhaps, paper roof covering or polyethylene are the most popular and budgetary. It is possible to refer their fragility to the main shortcomings of these materials. The special film membrane and the foiled isolation are considered as more modern and reliable.