Pre-Purchase Damp Survey for Buyers, Lenders and Vendors
“Further investigation recommended” on a valuation or homebuyer report is where many purchases stall. An independent damp survey answers it in days, with no repair to sell.
A pre-purchase damp survey (often called a homebuyer damp survey) is a specialist inspection commissioned when a RICS Level 2 or Level 3 survey, or the lender’s mortgage valuation, raises a concern about damp, timber or ventilation. Lenders respond with a condition, a mortgage retention, or a request for a specialist report. Buyers want to know what they are taking on and what it will cost. Vendors increasingly commission a pre-sale survey so that a damp comment does not derail the chain.
Why independence matters at this stage
The traditional route is a free damp survey from a treatment company. The report is free because the company earns from the chemical damp-proof course and re-plastering it then recommends. DML charges for the survey and does not carry out repairs. If treatment is needed, the report says so and sets out the scope for any contractor to price, including our team if you want a quotation. If treatment is not needed, which is common, the report says that instead and the retention argument is won on evidence.
What the survey covers
- Every ground-floor wall profiled for rising damp, with salt indicators where readings are raised
- External walls, chimney breasts and window reveals for penetrating damp
- Humidity, surface temperature and ventilation for condensation risk
- Sub-floor voids, joist ends and skirtings where access exists; roof timbers where accessible
- Visible plumbing, bathrooms and kitchens for leak evidence
- Ground levels, paths, gullies and downpipes that bridge the damp-proof course
- Existing damp proofing guarantees and what they actually cover
- A costed repair scope where the lender needs a figure to release a retention
Situations we are asked about every week
- Mortgage retention. The lender holds back part of the advance until specified works are done. Our report defines the works precisely so the retention is not inflated by a generic quotation.
- Lender condition: “specialist damp and timber report required”. We produce a damp and timber report. If the lender names a particular qualification or format, tell us at booking and we confirm whether we meet it before you pay.
- Second opinion. You have had a free survey from a damp-proofing firm that quotes thousands for injection and tanking. An independent inspection often finds bridging, a leak or condensation instead.
- Vendor pre-sale survey. Sell with the damp question already answered.
- New build and snagging. Damp in a new home is usually construction moisture, a leak or a detailing defect. The report gives you the wording for the developer or warranty provider.
- Buy-to-let and licensing. Landlords buying for letting need to know the property will meet damp and mould standards and, where applicable, selective licensing conditions.
Timing
Inspections are usually one to three hours. Reports follow the visit, with the delivery date confirmed when you book, and are addressed to you for forwarding to your conveyancer, surveyor or lender. Where exchange is imminent, say so when you book.
We investigate across Greater London and Surrey. See areas we cover.
Frequently Asked Questions
The valuation says “further investigation recommended”. What do I actually need?
Usually a specialist damp or damp and timber report that confirms whether a defect exists, its extent, its cause and the cost to put right. That is what this survey produces.
Is a free damp survey good enough for my lender?
Some lenders accept them. The problem is not acceptance but reliability: the report is written by the company that profits from the recommended works. An independent report protects your negotiation as well as the lender.
Can you give a cost for the works?
The report includes a repair scope. Where a figure is needed, our team or any contractor can quote against it.
Will you look at the timber too?
Yes where there is access. Joist ends, skirtings, window boards and roof timbers are checked for wet rot, dry rot and beetle, and the report says what is active and what is historic.
Can the seller stop you lifting carpets or boards?
Access is agreed with the vendor or agent in advance. Where access is refused, the report records the limitation so the lender and your solicitor know what was and was not inspected.
Related services
Buying with a damp question hanging over it?
Independent pre-purchase damp surveys across London and Surrey, turned around to your timetable.
Last reviewed: 27 October 2026. Independent investigation and written reports. Repairs are quoted separately.