Rising damp is real, but it's far less common than many reports and quotes suggest, and plenty of damp is wrongly blamed on it. True rising damp shows a recognisable pattern at the base of ground-floor walls, usually with ground salts in the plaster, and it should be confirmed by a proper diagnosis before anyone injects anything.
There are two camps online. One says rising damp doesn’t exist and the whole damp proofing industry is a con. The other finds rising damp in every house it walks into. I don’t agree with either.
Rising damp is moisture from the ground being drawn up through the tiny pores in brick, stone and mortar by capillary action. Older houses built without a damp proof course (DPC), or where the DPC has been bridged or damaged, can genuinely suffer from it. I’ve seen it many times, and so has anyone who has worked on old Yorkshire terraces for long enough.
What I also see, week in and week out, is damp being called rising damp when it’s nothing of the sort. The usual suspects are:
- Condensation, with mould behind furniture and at low level on cold walls.
- Bridging, where soil, a raised patio, render, or debris in the cavity lets moisture bypass a DPC that is still working.
- Penetrating damp from leaking gutters, downpipes, failed pointing or plumbing leaks.
- Old salt-contaminated plaster that keeps giving high meter readings long after the original problem has gone.
Real rising damp tends to have a pattern. It affects ground-floor walls from the bottom up, it’s generally fairly even along the wall rather than in random patches, and it fades out at a height where evaporation balances the moisture coming up. It brings ground salts with it, which is why you often see a tide mark, fluffy white salts and plaster that’s blowing or crumbling. Damp in the middle of a wall, at ceiling height or upstairs is not rising damp.
So the honest answer is that rising damp isn’t a myth, but a diagnosis of rising damp should be backed up with evidence: readings at different heights, checking the outside of the building, and where needed taking samples to measure moisture and salts properly. It shouldn’t be based on a quick prod with a meter at skirting level.
And if rising damp is confirmed, check for bridging first. Lowering ground levels or clearing a blocked cavity can sometimes solve it without any injection at all.
When to call a specialist
If you've been told you have rising damp and the diagnosis is based on a damp meter alone, it's worth a second opinion before you pay for a new DPC. Book a survey with All Dry on 01226 287181 or email info@alldrydampproofing.com.
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Frequently asked questions
What does rising damp look like?
Typically a tide mark low on ground-floor walls, salt deposits, and blown or crumbling plaster and decorations from skirting level up.
Can rising damp reach upstairs?
No; damp on upper floors points to another cause such as penetrating damp, leaks or condensation.
Do houses without a DPC always get rising damp?
Not always; it depends on the materials, ground conditions and how well the wall can dry out, which is why each property needs assessing.