As a natural moisture barrier can create comfortable living conditions each interested client knows it – the vapour barrier. It is a layer that is attached on the inside of a wall and hindered the diffusion of water vapour. It is intended to prevent a moisture of the insulation layer by water vapour. Correctly termed a vapour barrier. Used in engineering as a foil or cardboard, the vapor retarder limits the diffusion of water vapor in the insulation of a building.
In modern films, the vapor permeability is variable. The moisture may be given off back from the insulation into the space, prevents the diffusion is outwards. Originally, the idea that a wall had, can breathe to make hygienic and comfortable living conditions, goes back to the theory of Max von chaired. This theory was popular in the further result in various dashed. Pettenkofer air exchange through the room walls is essential for cleaning the air of the room. Later It recognized the significant role of the water vapour diffusion in the moisture balance of a component. To prevent the entry of moisture, although the ideal would be, however not be feasible.
Some authors said a greater naturalness to the water vapor permeability of materials such as brick or wood when compared to modern building materials such as glass, concrete or plastics. Natural materials such as, for example, block beams in a wooden house ensure the necessary removal of humidity through the wall and prevent an excessive humidity in the room at the same time. The breathing ability”a solid wood wall guarantees a substantial moisture tolerance in this sense so and thus ensures that the relative humidity does not exceed 80% in a wooden house. “Using vapor components such as vapour barriers/vapor barriers in a concrete or stone construction is, however, often the fear we live like in a plastic bag”, because the desired effect of the buffer is no longer available.