Control of Rising Dampness

Most buildings and decorative materials are sensitive to moisture. Damage occurs depending upon the level of relative humidity. Each material has a critical level at which trouble begins.

Damp movement

Damp movement occurs from the sub-base in two forms, as liquid water and as water vapour. Provided that the foundation is well-drained, liquid water can only rise up through the sub-base by surface tension between solid particles - know as capillary action - the smaller the particles, the higher water will rise. In addition water vapour can move along in the spaces between particles - defined as diffusion - the direction and rate of movement is dependent upon damp pressure.

Damage

If the passage of moisture and penetrating water is allowed to continue then defects and deterioration of the internal surface will take place.

Typical indications of moisture ingress are degradations to plaster/render resulting in cracking or debonding from the substrate, decorative finishes discolouring or peeling away from the plaster, rotting of skirtings, doorframes and architraves, pungent musty odours and mould growth.