Rising Damp in Buildings: What Causes It and How Can It Be Treated?
Rising damp is one of the most commonly misunderstood moisture problems in buildings. It occurs when moisture from the ground travels upward through porous materials such as bricks, blocks, stone and mortar through a process known as capillary action.
Where a building has no effective damp-proof course, or where the existing damp-proof course has been damaged or bridged, groundwater can gradually move upward through the walls.
In Uganda, damp-related defects may become particularly noticeable during prolonged wet periods or in buildings constructed on sites with poor drainage and high moisture levels.
Common signs of rising damp
Property owners should investigate when they notice symptoms such as:
- peeling or blistering paint;
- crumbling plaster;
- a visible damp or tide mark near the bottom of walls;
- white salt deposits or efflorescence;
- damaged skirting boards;
- musty odours;
- staining around floor and wall junctions; and
- persistent dampness despite repainting.
However, a damp wall does not automatically mean rising damp. Similar symptoms can be caused by leaking plumbing, rainwater penetration, defective gutters, condensation or high external ground levels.
Correct diagnosis is therefore essential.
How Rising Damp Is Treated
Treatment should address both the source of moisture and the damage already caused.
Where the existing damp-proof course has failed or is missing, a remedial damp-proof course may be introduced. One method involves injecting a specialist damp-proofing cream into a selected mortar joint.
The treatment creates a water-repellent zone designed to restrict further capillary movement of moisture.
Any conditions bridging the damp-proof course should also be corrected. This may include lowering external soil or paving, removing defective render or improving drainage.
Salt-contaminated plaster may also require removal and replacement with an appropriate replastering system.
Simply repainting a damp wall generally treats the appearance rather than the cause.
Tetrabuild's approach
At Tetrabuild Services Limited, damp treatment begins with inspection and diagnosis. The objective is to identify how moisture is entering the structure before recommending a waterproofing or damp-proofing solution.
Related articles: How to Prevent Rising Damp During Construction and Treating Existing Rising Damp with Chemical DPC Systems.
