Rising Damp Investigation in London and Surrey
Genuine rising damp is less common than the number of chemical damp-proof courses sold would suggest. We confirm or rule it out with evidence before any treatment is recommended.
Rising damp is ground moisture drawn up through porous masonry by capillary action, usually where a damp-proof course (DPC) is missing, failed or bridged. It produces a tide mark typically up to about a metre above floor level, salt deposits and blown plaster. The difficulty is that penetrating damp, condensation, plumbing leaks and high external ground levels can all produce similar staining at low level. Treating the wrong one wastes money and leaves the real problem in place.
How DML diagnoses rising damp
- Moisture profiling at set heights up the wall, inside and where possible outside, to see whether readings follow a rising pattern.
- Salts analysis where relevant: nitrates and chlorides from the ground are a strong indicator of true rising damp; their absence points elsewhere.
- DPC and bridging check: ground levels, paths, renders, internal floors and debris in cavities that bypass an otherwise sound DPC.
- Ruling out the alternatives: leaking pipework and drains, defective pointing or render, and condensation behind furniture, using thermal imaging and leak-detection methods where appropriate.
- Written report with readings, photographs, the mechanism we found and a repair scope that any contractor can price.
Typical causes we find
- Raised external ground, patios or flower beds bridging the DPC
- Cement render or internal plaster carried below DPC level
- Failed or absent DPC in older solid-wall properties
- Debris or mortar snots in cavities
- Leaking supply or waste pipes at low level, misread as rising damp
- Hygroscopic salts in old plaster drawing moisture from the air long after the original problem was fixed
Treatment: specified, not sold
If rising damp is confirmed, the report sets out what needs to happen: lowering ground levels, removing bridging, re-plastering with a salt-resistant system, and a new DPC where one is genuinely needed. If it is not rising damp, you will be told what it is instead. Remedial works are quoted separately by our team or your own contractor, so the diagnosis is never influenced by the treatment that follows. See damp proofing and damp treatment.
We investigate across Greater London and Surrey. See areas we cover.
Frequently Asked Questions
What are the signs of rising damp?
A horizontal tide mark up to about a metre high, white salt deposits, blown or crumbling plaster, rotting skirting boards and a musty smell at low level. These signs alone do not prove rising damp, which is why we test.
Can you tell rising damp from condensation?
Yes. Moisture profiles, surface and air temperature readings, salts analysis and the pattern of the staining usually make the distinction clear. Condensation sits on cold surfaces and behind furniture; rising damp follows the masonry.
Do I need a chemical damp-proof course?
Only if the existing DPC has genuinely failed or is absent. Many cases are bridging or leaks and are solved without injection. Our report will say which applies to your property.
Will a mortgage lender accept your report?
Our rising damp findings are presented as a damp and timber report when needed for a purchase or retention. Tell us the lender’s requirements when booking.
How quickly can you attend?
Usually within a few days across London and Surrey, with faster attendance where a sale or claim is time-critical.
Related services
Not sure it is rising damp?
Book an independent investigation. We confirm the cause before anyone recommends treatment.
Last reviewed: 25 October 2026. Independent investigation and written reports. Repairs are quoted separately.