How to Tell If a Damp Survey Company Is Overselling You

The damp-proofing industry has a structural conflict of interest that’s worth understanding before you get a survey: many companies offer a free or cheap survey, then make their money from the treatment work they recommend afterwards. That doesn’t mean every survey is dishonest, but it does mean the incentives aren’t neutral — and it’s a big part of why rising damp gets diagnosed far more often than genuine cases actually occur.

Warning signs

• A “free survey” that always seems to find the most expensive problem. Free surveys aren’t inherently dishonest, but treat a free-survey “rising damp” diagnosis with more scepticism than a paid, independent one.
• No mention of condensation as a possibility, even though it’s by far the most common cause of damp in UK homes. If a surveyor jumps straight to rising or penetrating damp without asking about ventilation, heating patterns, and where exactly the damp appears, that’s a red flag.
• A diagnosis based on a moisture meter reading alone. Hand-held “damp meters” often used in quick surveys can give misleadingly high readings on walls that contain modern gypsum plaster, foil-backed wallpaper, or certain plasterboard adhesives, none of which mean rising damp — they mean the meter is picking up something other than groundwater.
• Pressure to sign on the day, or a quote that expires within 24–48 hours.
• No explanation of why it isn’t condensation, when asked directly.

Questions worth asking

• “What specifically rules out condensation here?”
• “Is there tide-mark staining or efflorescence, and can you show me?”
• “Does the damp extend above roughly a metre from the floor?” (If yes, it isn’t rising damp.)
• “Can I get a second, independent opinion before agreeing to the work?”

Getting an independent opinion

A chartered surveyor (look for RICS accreditation) who isn’t also selling the treatment has no financial incentive to over-diagnose. For anything beyond a small, cheap fix, the cost of an independent survey is often worth it to avoid paying for unnecessary chemical DPC injection or other treatment that won’t actually solve a condensation problem.