
Search results for a local damp firm rarely tell you anything useful. You’ll be fed a list of names, a few star ratings, maybe a phone number, but nothing that separates a contractor who truly knows what they’re doing from one who’s learned to sound convincing over the phone. That gap is where most of the bad experiences in this trade start.
It matters more here than in a lot of other trades. Get a boiler repair wrong, and you’ll know within a week. Get a damp diagnosis wrong, and the wall may look fine for months before the same staining reappears, by which point you’ve paid once for nothing, and you’re back at square one. Landlords chasing a tenant complaint, buyers acting on a surveyor’s note, and homeowners who’ve watched a patch return after redecorating all end up asking the same question. This guide sets out what to realistically check before agreeing to any work, in the order it’s worth checking it.
Start with what they’re accredited to do
Nobody needs a licence to call themselves a damp proofing contractor. There’s no equivalent of Gas Safe registration for this trade, which means the range of people offering the service stretches from genuinely skilled specialists to people who bought some equipment and printed some business cards.
The Property Care Association is the closest thing the industry has to a recognised standard, and its members are held to technical guidelines that non-members simply aren’t. TrustMark, a government-backed scheme covering a range of trades including damp treatment, is another marker worth looking for. Nordic Damp Proofing sits among the damp proofing experts South West property owners can verify against these standards, working across Dorset, Hampshire, Bristol, Bath and the surrounding area rather than treating the region as an afterthought on a national coverage map.
Accreditation is a starting point rather than the whole picture, so it’s worth asking how long a company has held it too, since a newer membership can mean less time for standards to have properly bedded into how a firm operates day to day. A contractor who’s held accreditation for years, and can point to the survey work behind it, usually has more to show for it than one who joined last month.
Find out what happens before they quote
This is the single biggest tell. A contractor who names a price without visiting the property is skipping the part of the job that really matters. Damp can come from condensation, penetrating moisture, salts left behind in old plaster, poor ventilation or a damp proof course that’s failed or was never fitted, and several of these appear near enough identical from the outside.
Older properties across the South West, particularly anything built before the 1950s, get misdiagnosed more often than most. A previous owner’s repair job using the wrong materials can mask what’s actually going on underneath, and a contractor working from a five-minute look round has no way of catching that. Solid-walled Victorian and Edwardian terraces are especially prone to this, since they respond to moisture very differently from the cavity-walled housing built from the 1950s onward, and a contractor used to newer construction can misread what a solid wall is actually doing.
Ask what equipment they use to take moisture readings, whether they inspect ventilation and ground levels as standard and whether you’ll get anything in writing afterwards. A contractor confident in their process answers all three without hesitation.
Get everything in writing before you agree to anything
A verbal quote isn’t a quote. What you want is a document that sets out the work proposed, the reasoning behind it tied back to what the survey found and a full cost breakdown rather than a single number covering everything at once.
The guarantee terms belong in that same conversation. Ask what’s covered, for how long and whether it’s backed independently of the contractor’s own trading position, since a guarantee is only worth as much as the company still being around to honour it. If a contractor is vague about any of this, treat that vagueness as an answer in itself, and ask yourself whether you’d accept the same level of detail from a solicitor or an accountant.
Don’t settle on the first quote you get
Searching for damp proofing companies near you will bring back more options than anyone can reasonably compare on price alone, so get at least two surveys before deciding. Cheapest does not mean best value here. A low quote from a contractor who didn’t properly inspect the property tends to cost more in the long run than a fair price from one who did.
Line the quotes up against each other properly. Look at what each contractor actually found during their survey, how they explained it and whether the treatment recommended matches the cause identified, rather than defaulting to whoever comes in cheapest on paper. Among the damp proofing contractors you shortlist, the one worth choosing is usually the one whose report you understand best, not the one with the slickest sales pitch.
Pay attention to how they talk about the problem
The way a contractor discusses your situation tells you almost as much as their paperwork. Anyone pushing you to decide immediately, or warning that the property is at serious risk if work does not start today, is using urgency instead of evidence. A genuine assessment doesn’t need to be rushed through in an afternoon.
Be equally wary of anyone offering a diagnosis from a couple of photographs sent over email, or proposing the same fix regardless of what’s causing the problem. Rising damp, condensation and penetrating moisture each need a different response, and a contractor who hasn’t worked out which one applies to your property yet has no business recommending a treatment for it. If the explanation you’re given wouldn’t survive a follow-up question, it usually isn’t a complete one.
Making the call
The checks above take an afternoon at most and skipping them is exactly how people end up paying twice for the same wall. A contractor willing to show their accreditation, survey before quoting and put everything in writing has already demonstrated more than most will bother to.
Book a survey and find out what’s really happening in your property before any treatment gets recommended.





