Damp proofing buildings

Revision as of 13:42, 20 April 2018

The term ‘damp proofing’ is generally used to refer to types of moisture control that are applied to walls and floors to prevent damp from setting in and spreading in a building.

Excess water/moisture in all its forms (vapour, liquid, and flooding) is still the most common problem in housing. Damp problems are among the most frequent problems encountered in buildings, particularly older buildings which may have been constructed without a damp-proof membrane.

The most common causes of persistent damp in buildings are:

• Condensation (surface or interstitial).
• Rising damp.
• Penetrating damp.

The two most common damp proofing techniques are:

A damp-proof course is a barrier, usually formed by a membrane built into the walls of a property, typically 150 mm above ground level, to prevent damp rising through the walls. Damp-proof courses are now required in the construction of new buildings to prevent rising damp and in some situations to prevent penetrating damp.

For more information, see Damp proof course.

A damp-proof membrane (DPM) is a membrane material applied to prevent moisture transmission. Typically, a DPM is a polyethylene sheet laid under a concrete slab to prevent the concrete from gaining moisture through capillary action.

For more information, see Damp proof membrane.

Other damp proofing techniques include:

• Integral damp proofing: Concrete production can involve the addition of materials to make it more impermeable.
• Surface coating: Thin waterproof materials can be used such as a coating of cement sprayed on shotcrete.
• Cavity wall systems: A cavity separates the interior walls from the exterior walls.
• Pressure grouting: This can fill in cracks and joints in masonry.

Find out more

Related articles on Designing Buildings Wiki

• Basement waterproofing.
• Condensation.
• Damp.
• Damp-proof course.
• Damp-proof membrane.
• Humidity.
• Mould growth.
• Penetrating damp.
• Rising damp.
• Spalling.
• Structural waterproofing consultant.
• Tanking.
• Understanding dampness.
• Wall insulation and moisture risk.
• Water.