Damp · Guide
7 Signs of Rising Damp (and How to Tell It From a Roof Leak)
Quick answer
Rising damp shows as a tide mark, salt bloom and peeling paint on the bottom metre of walls, present even in dry weather. Damp higher up that worsens after rain is penetrating damp or a roof or parapet leak, which needs a different fix.
The seven signs
- A horizontal tide mark up to about a metre high.
- White, fluffy salt deposits (efflorescence) on plaster.
- Paint bubbling or flaking near skirting boards.
- Crumbling plaster at the base of walls.
- Rotting skirting boards or timber floors.
- A musty smell in rooms on the ground floor.
- Damp that doesn't change much between dry and rainy weeks.
Rising damp or something else?
If the damp is high on the wall, under a flat roof or parapet, or appears a day or two after rain, it's coming from above or through the wall, not from the ground. That's a job for parapet and slab waterproofing or roof leak repairs.
What fixes rising damp
First remove anything bridging the damp-proof course, such as raised paving, soil or plaster run to the ground. Then, if needed, a chemical damp-proof course is injected, and damaged plaster is replaced with a salt-resistant render. See damp proofing in Pretoria East.