What a Damp Survey
Costs in London

Last reviewed September 2026 by Tony Murphy, Founder & Managing Director. We update these guides in place rather than letting them go stale.

What Does a Damp Survey Actually Cost?

A damp survey in London costs between £180 and £395 including VAT for most residential property, with the variation driven by what needs inspecting rather than by the size of the house. A single damp patch in a two-bed flat sits at the bottom of that range. A four-storey Victorian terrace with a cellar, suspended timber floors and three separate problem areas sits at the top.

Why Is a Free Damp Survey Not Free?

A free survey is not a survey. It is a sales visit, and the person carrying it out is paid from the work it generates. That is not a character flaw in the individual — it is a structural incentive, and it produces a predictable outcome: free surveys find chargeable work at a far higher rate than paid ones.

The cost has not disappeared. It has moved into the quote, along with the cost of every other free survey that did not convert. You are paying for it either way. The difference is that with a paid survey you own a written report and a diagnosis, and the surveyor can afford to tell you that you do not need them.

We charge for surveys and deduct the fee from the cost of works if you proceed. A meaningful proportion of our surveys conclude that the property needs a roofer, a plumber or a working extract fan rather than a damp specialist. We can say that because we have already been paid to look.

What Do You Get for the Money?

A survey worth paying for takes one to three hours on site and produces a written document within a couple of days. It should include:

• An external inspection. Ground levels against the damp proof course, hard landscaping, gullies and drainage, rainwater goods, pointing, render, sills, flashings and airbricks. Most internal damp patches are caused by something outside.
• Moisture profiling. Readings taken at intervals up the wall, and from drilled masonry samples where the diagnosis requires it — not a single surface reading from a handheld meter.
• Salts analysis. Testing for hygroscopic nitrates and chlorides, which is what distinguishes genuine rising damp from salt contamination left over from a historic problem.
• Thermal imaging where condensation, cold bridging or a concealed leak is suspected.
• A written report with photographs, the diagnosis and the reasoning behind it, a specification, an itemised fixed price and the guarantee terms.

If what you are offered is a visit and a verbal quote, that is not a survey however much or little it costs.

Why Do Surface Moisture Meters Mislead?

The handheld meters you see on most damp visits measure electrical conductivity between two pins. Water conducts, so the meter is a reasonable proxy for moisture in timber — which is what these instruments were designed for.

On masonry and plaster it is far less reliable. Hygroscopic salts conduct. Foil-backed plasterboard conducts. Metal mesh, certain paints and some plasters conduct. A meter can read "damp" on a wall that is bone dry but salt-contaminated from a problem solved fifteen years ago, and that false positive is one of the most common reasons properties get injected unnecessarily.

This is why a proper survey uses profiling and salts analysis rather than a surface reading alone.

Is the Survey Fee Refundable?

With us, the fee is deducted from the cost of works if you go ahead — so if the survey costs £250 and the works come to £2,400, you pay £2,150 for the works. It is not refunded as cash if you decide not to proceed, because the report itself is the thing you bought, and it remains yours to take to another contractor.

Check this before booking with anyone. "Deducted from the works" and "free if you proceed" are the same thing. "Refundable" sometimes turns out to mean neither.