Damp surveys, and why the free one exists
A home survey is built to pass a damp question onward, not to answer it. What RICS promises, what the free survey is really for, and when paying for one is the cheapest decision you make.
By The Damp GuyLast updated
The short version
A RICS home survey flagging damp is not a diagnosis, and was never meant to be. RICS's own description of the service says the surveyor does not force or open up the fabric of the building and uses a damp meter, and that where no confident conclusion is reachable the surveyor should make a recommendation for further investigation. So the survey routes you onward, correctly. Your question is where to. The free survey comes from companies that quote for the treatment. That is not an accusation, it is a fact worth holding. An independent survey is published at £150 to £600, depending on the property. Against a treatment costing thousands, that buys you an opinion from someone with nothing to sell you.
What a home survey actually promises
RICS publishes the service description. It is short, it is public, and it beats anything written about it.
On the inspection: "The surveyor does not force or open up the fabric of the building. This includes taking up fitted carpets, fitted floor coverings or floorboards; moving heavy furniture; removing the contents of cupboards, roof spaces, etc.; removing secured panels and/or hatches; or undoing electrical fittings."
On the kit: "The surveyor uses equipment such as a damp meter, binoculars and torch."
Now hold that against what settling a damp diagnosis requires. BS 6576's wording is that surface measurements cannot alone give proof of rising damp, and that further evidence comes from measurements taken within the depth of the wall. A meter, meanwhile, reports a wood moisture equivalent on plaster and masonry, and salts and buried metal both read as water.
Put those together and the conclusion is structural, not critical. A surveyor confined to a non-invasive inspection, holding an instrument that cannot separate the kinds of moisture, cannot settle which kind of damp you have. RICS does not pretend otherwise. The service scopes risk across a whole property in a limited visit, and it is good at that.
Which is why your report says what it says. "Where the surveyor is unable to reach a conclusion with reasonable confidence, a recommendation for further investigation should be made." A condition rating 3 means defects that are serious and/or need to be repaired, replaced or investigated urgently.
So who does the further investigation?
A damp flag means the survey worked. This next bit is the hinge, and it decides a lot of money.
The obvious route is the free damp survey. Advertised everywhere, costs nothing, usually happens this week, and the person who turns up knows a great deal about damp. No trick is being described here, and nobody is being called dishonest.
Just be clear what you are getting. A free survey is a sales visit with an inspection in it, run by a business whose income is the remedial work. The survey is not the product. The treatment is the product, and the survey is how it gets specified.
That can produce a perfectly accurate diagnosis, and often does. It is simply not a second opinion, because it is not independent of the outcome.
The industry itself has written down the standard that ought to apply. RICS, Historic England and the Property Care Association produced a Joint Position Statement, "Investigation of moisture and its effect on traditional buildings: Principles and competencies", with further support from Historic Environment Scotland, Cadw, the Historic Environment Division in Northern Ireland, the SPAB and the IHBC. It says the surveyor should take a whole building approach, look for the source of any excessive moisture, not rely on potentially misleading data, make professional judgements rather than simply make recommendations, and take responsibility for the advice given.
The Property Care Association co-authored that. It is the trade body for the firms selling the treatment. It has still put its name to a document saying find the source, and do not lean on data that can mislead. That is the bar. Hold any survey against it, free or paid.
What you are choosing between
Three different products go by the name damp survey, and they answer different questions.
| What it is | Cost | What it can establish | Who it answers to |
|---|---|---|---|
| RICS home survey | Part of the purchase survey | That there is something worth investigating, across the whole property | You, and it is non-invasive by definition |
| Free damp survey | Nothing up front | A specification for remedial work, quickly | A business whose income is that work |
| Paid independent survey | £150 to £600 by property size | Depends entirely on whether it goes into the wall | You, if the surveyor does not also sell the cure |
Those independent fees are published as £150 to £250 for a two-bed flat, £300 to £400 for a three-bed terrace or semi, and £450 to £600 for a four-bed detached. Set that against what the treatment and the making-good cost and the survey stops looking like the expensive option.
What makes a paid survey worth paying for
Paying does not buy you independence or depth on its own. Two things decide whether the fee earned itself.
Does the surveyor benefit from the answer? If the same business would do the remedial work, your report is not independent, however much you paid for it. Ask outright whether they, or any company they are connected to, would tender for the work they recommend.
Does it go beyond the surface? A report built on meter readings off the face of the plaster carries the same limit as the free one, and as the home survey. What changes the picture is evidence from within the wall. That means drilled samples analysed by carbide or gravimetric methods, plus a look outside at the things putting water in.
About the letters. Most damp surveyors carry CSRT, the Certificated Surveyor in Remedial Treatments, since renamed CSTDB, Certificated Surveyor of Timber and Dampness in Buildings. Now you know what the initials stand for. I will not rate the qualification. Everyone writing about it has a position in that argument, and I have found no neutral assessment worth passing on.
What to ask before you book anything
You have decided somebody needs to look at it. All that is left is choosing who, and these questions do the choosing.
- Would you, or anyone you are connected to, quote for the work you recommend? One question, and it settles what kind of report you are buying.
- Will you take samples from within the wall, or work from surface readings? Surface readings only, and the report cannot conclude more than your home survey already did.
- Will you look outside as well as inside? Ground levels, gutters, pointing and the roof are where a great many internal damp patches begin.
- What will the report contain? A written report with findings and reasoning is not the same animal as a quotation with a paragraph at the top.
- If you find nothing needing treatment, what do I pay? The answer tells you what the visit is really for.
About this resource
The wording on what a home survey does and does not do is quoted from RICS's own published description of the RICS Home Survey Level 2 (survey only). The principles come from the 2022 Joint Position Statement by RICS, Historic England and the Property Care Association. The survey fees are a published range from a commercially interested trade cost source, dated August 2026. They are not a quote. Only the Level 2 document was read, so nothing here describes Level 3 in detail.
Nothing on this page calls any company dishonest, and no company is named. The point is who benefits from an answer, which you can check. Not anyone's character, which you cannot. This site does not survey, treat, quote or refer, and takes no fee from anyone who does.
Common questions
Is it illegal to sell a house with damp?
No. Selling a house with damp is not illegal and there is no duty to volunteer a survey of your own faults. What there is instead is the Law Society's TA6 Property Information Form, which sellers complete and buyers are told they can rely on. The form itself is blunt about what follows: if you give misleading information, the buyer may be able to claim compensation after completion. Under the Misrepresentation Act 1967 that liability holds even where the answer was not given dishonestly, unless the seller had reasonable ground to believe it was true.
Do I have to declare damp on the TA6 form?
This surprises people. The only question on the TA6 that mentions damp at all asks whether the property has an unexpired damp proofing guarantee, and if it does, for a copy of it. There is no box asking whether the walls are wet. The duty is not a damp disclosure box, it is the standard the whole form is answered to: truthfully, completely and as accurately as you can from your own knowledge, with a reasonable basis for what you say, and saying so where you do not know.
Can you hide damp from a surveyor?
For a morning, yes, and that is the uncomfortable part. A Level 2 surveyor does not force or open up the fabric of the building, does not move heavy furniture and does not take up floor coverings, so fresh paint and a wardrobe in the right place change what is visible. It does not change what is answered on the TA6, and a buyer who finds it afterwards is holding a form the seller signed as truthful and complete.
Will a Level 2 survey pick up damp?
It will usually flag it, and that is the service working correctly rather than failing. RICS's own description has the surveyor carrying a damp meter and not opening up the fabric, which is enough to notice damp and structurally not enough to say which kind it is. A condition rating 3 means defects that are serious and need to be repaired, replaced or investigated urgently, and where no confident conclusion is reachable the surveyor should recommend further investigation.
What happens if damp is found on a survey?
Nothing automatic. The report hands you a flag and a recommendation, and every consequence after that is negotiated: a retention, a price reduction, a condition of sale, or nothing at all. The mistake worth avoiding is treating the flag as a diagnosis and going straight to a treatment quote, because the quote then sets the size of the renegotiation without anyone having established what is actually wrong.
Are damp surveys worth paying for?
Set the fee against what it decides. Independent survey fees are published at £150 to £250 for a two-bed flat and £450 to £600 for a four-bed detached, against damp work that runs into thousands and is not refundable when the wrong problem gets treated. Paying does not buy independence by itself, though. What buys it is an inspection from someone who would not tender for the work they recommend, and who takes evidence from inside the wall rather than off the face of the plaster.