Independent damp surveys vs "free" surveys – and what a survey should include
Why independence matters
RICS recommends asking for a survey that complies with the Joint Position Statement 2022 (JPS22), published by RICS, Historic England and the Property Care Association. RICS says a JPS-compliant report gives an unbiased professional opinion from someone without a commercial interest in selling you a product, and only suggests remedial works that are proportionate and respect the property (RICS; JPS 2022).
A free survey from a company that sells damp-proofing isn't necessarily wrong, but the JPS expects them to declare any treatment or product that would benefit them financially (JPS 2022). Ask them directly.
Warning signs
- "You've got rising damp and need a new damp-proof course." RICS calls this a typical misdiagnosis: "rising damp" doesn't identify where the moisture is coming from, and failure of an original damp-proof course is extremely rare (RICS).
- Diagnosis with a damp meter alone. Damp meters are accurate for timber, but on other materials they can give high readings from salts and other conductive materials (RICS).
- Treatment before maintenance. RICS advises against installing expensive damp-proofing without first doing routine maintenance and asking what has changed (RICS).
What a good survey covers
- The building: its age, construction, alterations and setting – including whether it's a traditional solid-walled building that absorbs moisture and dries out (JPS 2022).
- Outside checks: gutters and downpipes, roof flashings, pointing, cracked render, ground levels, blocked vents, drainage and leaking pipes (RICS).
- Inside checks: where the damp and mould are, ventilation, heating and how the home is used.
- Measurements: the right tools for the job – which can include hygrometers, surface thermometers, data loggers, thermal imaging, and laboratory moisture tests on samples (JPS 2022).
- A clear report: an impartial diagnosis, prioritised recommendations, alternative options with pros, cons, costs and timescales, a maintenance plan, and any conflicts of interest declared (JPS 2022).
Who to instruct
RICS says membership alone doesn't make someone a damp specialist. Look for an RICS building surveyor (AssocRICS, MRICS or FRICS) with experience in building pathology, and ask to see their CV (RICS). Government guidance also lists damp surveying qualifications such as CSRT, CSSW, CRDS and CSDTB (GOV.UK).
Do I need one if I'm buying?
An RICS Home Survey records visible defects; where it finds signs of damp it may recommend further investigation (RICS). Some mortgage lenders ask for a damp and timber survey before lending (Checkatrade).