Moistureproofing

the protection of aboveground structures of buildings and installations from excessive moisture, as well as the methods used to attain this goal.

Moisture-insulating materials are usually used to protect against moisture; the installation of drainage layers or air seams that limit the penetration of moisture and that shift position only under the influence of capillary forces (for ex-ample, atmospheric forces or moisture from upper soil layers in the absence of hydrostatic pressure) is also possible. The degree of wetting of exterior structural components by the humidity of the interior air is limited by using moisture-impermeable materials on the surface that faces the enclosed area or on the interior part of the structural component, as close as possible to this surface. Thick plaster, impermeable paint, facing tiles, water-resistant rolled roofing materials, and cement with hydrophobic (moisture-repellant) additives are used as moistureproofing materials.

Moistureproofing that eliminates wetting from condensation of moisture on the surfaces of structural components facing into the enclosed area is used in buildings with high relative humidity of the interior air; when the humidity is not high in heated areas, such wetting is eliminated by increasing the heat-insulation properties of the structure and by raising the temperature of its surface higher than the dew point.

In exterior structural components of buildings the most effective moistureproofing, which protects against the diffusion of moisture from the enclosed area, is required for the internal part of ceilings with rolled roofing material, as well as for the walls, which are heated from within by porous materials. A considerably lesser degree of moistureproofing is possible for walls with a dense interior section, heated from the outside.

Protective painting of facades with impermeable compounds (for example, postchlorinated polyvinyl chloride), as well as special facings that are separated from the walls by air seams, is used for protection against wetting of walls by atmospheric moisture.

In moistureproofing joints and connections between major wall components, the location within the joints of moisture-insulating linings (composed, for example, of elastic plastics), the installation of horizontal joints with antirain barriers, and the mounting of drainage channels in vertical joints are used in addition to the usual water-removal devices (drains, slip rings, and so on).