- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 24 Mar 2021
Rising damp in walls - diagnosis and treatment (DG 245)
On 12 October 2007, BRE published Rising damp in walls - diagnosis and treatment (DG 245 revised edition), written by Peter Trotman.
- The rate of evaporation from the wall.
- The porosity of the wall.
- The salt content of the wall and soil.
- The groundwater height and saturation.
- Heating in the building.
Some accumulation of salts can occur in the walls of old buildings even when they do not have a damp problem, so high readings from a moisture meter alone are not conclusive. Appendix A of the 12-page digest describes how to drill samples from a wall in to test for moisture content and hygroscopicity, and the interpretation of moisture gradient profiles.
If a building has a physical damp-proof course (DPC), it is unlikely that it has failed, as most dpc materials have a long life, however, defects such as mortar droppings in a cavity wall, may make a dpc ineffective by bridging it and allowing moisture to pass up through the wall. This and other mechanisms by which an existing dpc might be bridged are discussed.
The content of the digest includes:
- Mechanism of rising damp.
- Determining the source of the dampness.
- Dry lining.
- Further reading.
- Appendix: The sampling method.
 Related articles on Designing Buildings Wiki
- Assessing moisture in porous building materials.
- BRE articles on Designing Buildings Wiki.
- Building Research Establishment.
- Carbide meter.
- Damp-proof course.
- Damp proof membrane.
- Defects in brickwork.
- Dew point.
- Diagnosing the causes of dampness (GR 5 revised).
- Does damp proofing work?
- Electrical resistance meters.
- Interstitial condensation.
- Mould growth.
- Penetrating damp.
- Psychometric chart.
- Rising damp.
- Sling psychrometer.
- Treating brickwork with sealant or water repellent.
- Understanding dampness.
 External references
- BRE Digest 245, Rising damp in walls - diagnosis and treatment.
- Good Repair Guide 33 - GRG33.
Featured articles and news
Predictions about adequate post-pandemic IAQ in non-domestic buildings.
Government publishes plans to 'build back greener'.
The contentious nature of claims associated with cladding, fire safety and EWS1 forms.
ECA comments on low-carbon heating systems initiative and Heat and Buildings Strategy.
Cinders and other forms of domestic rubbish created filth but also generated great wealth.
CIC 2050 Group requests input to find out priorities for future industry leaders.
IHBC publishes response to consultation.
Institute applauds funding initiatives but presses for additional retrofit and tax measures.
The switch from analogue to digital has begun.