Diagnosing the causes of dampness (GR 5 revised)

BRE (Building Research Establishment) is an independent, research-based consultancy, testing and training organisation, operating in the built environment and associated industries.

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:

• Introduction.
• Internal dampness: moisture from condensation.
• External dampness: rain penetration.
• External dampness: rising damp.
• Construction moisture.
• Leaking pipes.
• Leaking roofs.
• Spillage.
• Ground and surface water.
• Contaminating salts.
• Hidden dampness.
• Specialist inspection.
• References.

Other guides in the series, Good Repair Guides 6–8, cover specific remedial treatment for the principal causes of dampness.

--BRE Group

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