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Last edited 14 Dec 2020
Diagnosing the causes of dampness (GR 5 revised)
Diagnosing the causes of dampness (GR 5 revised) was written by John Houston and published by BRE on 18 March 2015.
Even in a ‘dry’ building, there is a surprising amount of water in porous materials, most of which does no harm. A building is only considered to be 'damp' if the moisture or its effects become visible, leading to deterioration in decorations or the fabric of the building.
Dampness is the most common problem in housing. It results in visible wetting of walls, ceilings and floors, blistering paint, bulging plaster, sulfate attack on brickwork and mould growth on surfaces and fabrics, usually accompanied by a musty smell. It can also lead to less obvious problems such as a reduction in the effectiveness of thermal insulation or cracks in brickwork due to the corrosion of embedded metal components.
The first step in solving damp-related problem is to diagnose the cause.
This Good Repair Guide provides advice on how to identify the potential causes of dampness in homes. It is aimed at housing professionals, home owners and occupiers, and replaces guidance published in 1997.
Its contents are:
- Internal dampness: moisture from condensation.
- External dampness: rain penetration.
- External dampness: rising damp.
- Construction moisture.
- Leaking pipes.
- Leaking roofs.
- Ground and surface water.
- Contaminating salts.
- Hidden dampness.
- Specialist inspection.
 Related articles on Designing Buildings Wiki
- Assessing moisture in porous building materials.
- BRE articles on Designing Buildings Wiki.
- BRE Buzz articles on Designing Buildings Wiki.
- BRE Buzz.
- Building damp-free cavity walls.
- Building Research Establishment.
- Damp in buildings.
- Damp proof membrane.
- Damp proofing.
- Damp-proof course.
- Dew point.
- Dry rot fungus.
- Interstitial condensation.
- Penetrating damp.
- Rising damp in walls - diagnosis and treatment (DG 245).
- Rising damp.
- Understanding dampness.
- Wall insulation and moisture risk.
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