Damp Treatment: Diagnosis First, Then the Right Fix
Rising damp, penetrating damp and condensation each need a different treatment. We confirm which one you actually have, specify the works in writing, and leave you free to choose who carries them out.
Short answer: most damp treatment that fails was the wrong treatment. Injecting a chemical damp proof course into a wall that is suffering from a leaking gutter or high ground levels does nothing. Damp Mould Leak investigates first: moisture profiling, salts analysis where relevant, thermal imaging and a check of the external defects that cause most damp. You receive a written diagnosis and a treatment specification. Works can then be quoted by our team or any contractor you prefer.
The three kinds of damp and what each needs
- Rising damp: ground moisture drawn up through masonry where a damp proof course is missing, bridged or failed. Treatment is usually a remedial DPC plus removal and replacement of salt-contaminated plaster, but only after bridging (raised ground, render, debris in cavities) has been ruled out. See rising damp.
- Penetrating damp: water getting in from outside through defective pointing, render, flashing, gutters, downpipes or window reveals. Treatment is to fix the defect, then let the wall dry and redecorate. See penetrating damp.
- Condensation: moisture generated inside the home settling on cold surfaces, producing black mould. Treatment is ventilation, heating pattern and insulation changes, plus mould treatment. See condensation.
What a DML damp investigation involves
- Moisture profiling of affected walls at several heights to distinguish rising from penetrating damp
- Salts analysis where readings suggest rising damp, because nitrates and chlorides are the signature of ground moisture
- Thermal imaging to locate cold bridges and hidden moisture
- External inspection of ground levels, DPC position, pointing, render, gutters and downpipes
- Internal checks for plumbing and heating leaks that mimic damp
- A written report with photographs, readings and a treatment specification
Treatment works and who does them
Your specification sets out what should be done: for example a remedial damp proof course and replastering to a stated height with a salt-resistant system, repointing a defined area, lowering an external ground level, or installing extract ventilation. Our team can quote for these works. So can any damp contractor or builder. Guarantees on treatment are provided by the contractor carrying out the work, in writing, before it starts.
Why this approach saves money
A damp proof course injection sold on the strength of a free survey is often unnecessary. Paying for an independent diagnosis first means you only commission works that address the real cause, and you have a document that a lender, buyer, insurer or landlord will accept as evidence.
Frequently Asked Questions
Do you carry out the damp treatment yourselves?
No. We diagnose and specify. Treatment works are quoted separately through our team or a contractor of your choice, so our diagnosis is never influenced by the value of the works.
Does damp treatment come with a guarantee?
Guarantees are given by the contractor who carries out the treatment, in writing, before works begin. Our report tells you what the guarantee should cover.
How much does damp treatment cost?
It depends entirely on the cause, the area affected and the works needed. That is exactly why we investigate first. The investigation itself is quoted before we attend.
Can you provide a report for a mortgage lender or surveyor?
Yes. Our reports are written to answer the valuer’s or surveyor’s note: what the damp is, what is causing it and what it will take to fix. See damp and timber reports.
Is rising damp real?
Yes, but it is diagnosed far more often than it occurs. Many cases are bridged DPCs, high ground levels, leaking pipes or condensation. Moisture profiling and salts analysis tell the difference.
How quickly can you attend?
Call 0800 054 1524 for the earliest available appointment across London and Surrey; urgent cases are prioritised.
Get the diagnosis before the treatment
Book a damp investigation in London or Surrey.
Last reviewed: 23 October 2026. Independent investigation and written reports. Repairs are quoted separately.