The short answer
Choose a damp-proofing specialist who is accredited (ideally PCA), works from an independent diagnosis, gives a written specification and a clear guarantee, and explains the cause — not just the cure. Get the diagnosis from someone who isn’t selling the treatment, then take at least two like-for-like quotes. Be wary of free surveys, hard-sell tactics, blanket “rising damp” verdicts and chemical injection proposed without evidence.
The damp-proofing trade has a reputation problem because the people who diagnose the damp are often the people who profit from treating it. You can sidestep almost all of the risk by separating diagnosis from treatment and applying a few simple checks. Here is how to choose a specialist you can trust, and the warning signs that tell you to walk away.
Choosing a specialist at a glance
- Accreditation PCA membership; CSRT/CSSW qualified staff
- Diagnosis Independent of whoever does the work
- Quotes At least two, like-for-like, in writing
- Guarantee Written, with insurance backing (IBG)
- Red flag Free survey + immediate hard sell
Start with an independent diagnosis
The single most important rule is to separate the diagnosis from the work. Establish the cause through someone who is not selling the cure — an independent damp survey — then ask specialists to quote against that report. This removes the incentive to over-specify treatment, and it means every quote you receive is for the same, correctly defined job rather than three different firms’ sales pitches. Without it, you are asking a salesperson to mark their own homework, and the predictable result is condensation diagnosed as rising damp and “solved” with chemicals.
Check accreditation and qualifications
- PCA membership — the Property Care Association vets members, requires a code of conduct, and offers a complaints route if work falls short.
- Qualified surveyors — look for the CSRT (Certificated Surveyor in Remedial Treatment) for damp and timber, or the CSSW (Certificated Surveyor in Structural Waterproofing) for below-ground work.
- Insurance — current public liability cover, and guarantees backed by an independent insurance-backed guarantee (IBG) policy so the cover survives if the firm ceases trading.
- Track record — verifiable references for similar properties, and a willingness to put everything in writing.
Compare quotes properly
Take at least two written quotes against the same independent diagnosis. A proper quote specifies the identified cause, the method, the materials, the exact area being treated, the guarantee terms and any making-good such as replastering. Vague pricing is a warning sign: if a contractor cannot tell you precisely what they are treating and why, they cannot stand behind the result. Be especially suspicious of a verbal “it’s rising damp” verdict that leads straight to an injected DPC and full replastering quote — that is the sector’s most common over-sale.
| Good sign | Warning sign |
|---|---|
| Works from an independent diagnosis | Diagnoses and sells the cure themselves |
| PCA-accredited, qualified staff | No verifiable accreditation |
| Written, insurance-backed guarantee | Verbal or self-backed guarantee only |
| Explains the cause clearly | Jumps straight to chemical injection |
After you choose
Diagnosis and treatment are different jobs
The single most useful habit when choosing a specialist is to separate the person who diagnoses the problem from the person who carries out the work. A contractor offering a free survey has a commercial interest in finding work to quote for, and the classic example is recommending an injected chemical damp-proof course for what is actually penetrating damp from a failed gutter or condensation from poor ventilation — an expensive cure for the wrong illness. An independent surveyor who sells no treatment has no such incentive, so their diagnosis is impartial. Use an accredited independent surveyor for the diagnosis, then take their written specification to one or more accredited contractors for competitive quotes against the same scope. That way you compare like with like, you avoid paying for unnecessary work, and you keep a clear paper trail from cause to cure to guarantee.
Once you have chosen, get the agreed scope, method and guarantee in writing before any work starts, and confirm who provides the insurance backing. Keep the written specification, invoice and guarantee documents safe — they matter for warranty claims and for future sales, when a buyer’s surveyor and solicitor will ask to see them. If the work is part of a purchase, check whether the guarantee is transferable to a new owner. This page is general information, not a recommendation of any particular firm and not legal advice; verify a specialist’s current accreditation and insurance directly before instructing them.
Want an impartial diagnosis before you hire anyone?
Start with an independent, accredited damp survey, then choose a specialist from facts. The enquiry is free and there’s no obligation.
Frequently asked questions
What accreditation should a damp-proofing specialist have?
Look for Property Care Association (PCA) membership and surveyors holding the CSRT or CSSW qualifications, plus public liability insurance and insurance-backed guarantees.
Should the same firm diagnose and treat the damp?
Ideally not. Getting the diagnosis from an independent surveyor first removes the incentive to over-specify treatment and lets you compare like-for-like quotes for the work.
How many quotes should I get?
At least two, in writing and against the same diagnosis. Each should specify the cause, method, area, materials, guarantee and making-good so you can compare them fairly.
What are the warning signs of a bad damp firm?
A free survey followed by hard-sell pressure, a blanket “rising damp” verdict without moisture evidence, no written specification, and guarantees with no independent insurance backing.
Sources & further reading
- Property Care Association (PCA) — choosing a member and code of conduct
- RICS — Investigation of moisture and its effects in traditional buildings
- gov.uk — Housing Health and Safety Rating System (HHSRS): damp and mould
This guide is general information, not a site-specific survey, medical advice or legal advice. Damp and mould should be assessed by a qualified surveyor, and health concerns discussed with a GP or the NHS.