Damp and Timber Reports Explained for House Buyers

What a damp and timber report is

A damp and timber report is a specialist inspection of a house for dampness and for timber decay: wet rot, dry rot and wood-boring insects. It looks closer than a home survey. A RICS Level 2 surveyor uses a damp meter and records what is visible, and where they cannot judge the cause with confidence they recommend further investigation. The damp and timber report is often that investigation.

Who writes them

Most damp and timber reports are written by surveyors employed by remedial treatment companies. The Property Care Association (PCA) is the trade body for these firms. Its surveyor qualification is the Certificated Surveyor of Timber and Dampness in Buildings (CSTDB), which replaced the older CSRT in 2018; CSRT holders are still recognised. The PCA's own search tool also lists independent surveyors, who report without carrying out the work.

RICS building surveyors with experience in building pathology also investigate damp. RICS's consumer guide notes that RICS membership alone does not mean a surveyor is experienced in damp, so ask about their experience with older houses.

Why mortgage lenders ask for them

The mortgage valuation is for the lender, not for you. If the valuer sees signs of damp, rot or woodworm, the lender may ask for a specialist report before it confirms the offer, or hold back part of the loan until the work is done. Each lender sets its own rules on what report it will accept and from whom, so ask your broker or lender before you book one, and ask your conveyancer how any condition affects your timetable.

Rising damp, penetrating damp and condensation

Type	What it is	Common causes in London houses	What usually fixes it
Condensation	Water vapour in the air settling on cold surfaces	Cooking, showers and drying washing with little ventilation or heat; cold solid walls	Heating, ventilation and extract fans, not damp-proofing
Penetrating damp	Water moving through a wall, roof or floor from outside	Leaking gutters and downpipes, failed pointing or render, roof and parapet defects, bridged walls	Repairing the outside: roof, rainwater goods, pointing, render
Rising damp	Ground moisture drawn up a wall	A missing or failed damp-proof course, or one bridged by raised paths, patios or render	Lowering ground levels and removing bridges first; a new damp-proof course only where it has genuinely failed
Leaks	Water from pipes, baths, showers or heating	Plumbing faults, failed seals	Repairing the leak and drying out

RICS's consumer guide says rising damp is often misdiagnosed. Condensation in a cold back room, or a wet wall under a leaking hopper, can look like rising damp at skirting level. Salts left in old plaster also draw moisture from the air and push meter readings up long after the source has gone.

Timber: rot and woodworm

Timber decay follows moisture. Wet rot is usually local to a leak or a wet wall; dry rot can spread through masonry and needs the moisture source found and removed. Woodworm in old houses is often historic and no longer active. Historic England's advice is to deal with the causes, not the symptoms: find and stop the water, then repair or replace only the timber that has failed.

The risk of a report that sells treatment

A report written by a company that also sells injection, tanking or timber treatment is not independent, however competent the surveyor. In September 2022 RICS, Historic England and the PCA published a joint position statement, Investigation of moisture and its effects on traditional buildings, later adopted by bodies including SPAB and Cadw. It asks for a whole-building approach, and says that finding moisture in an old building does not automatically make it a problem that needs fixing. RICS's guide adds that an inspection to that statement gives you an opinion from someone with no commercial interest in selling a product, and recommends only proportionate work.

Signs that a report is selling a product rather than giving a diagnosis:

• The diagnosis rests on a hand-held moisture meter alone; RICS warns against this, especially on solid walls
• Rising damp is diagnosed without looking at gutters, downpipes, ground levels, render and ventilation
• Every wall gets the same answer: injection and a strip of replastering at a fixed height
• Timber treatment is specified for all floors where no active decay or insect activity is shown
• The quote for the work arrives with the report, from the same firm

What a sound repair looks like on a London period house

Victorian and Edwardian houses were built with solid brick walls and soft lime mortars that let moisture in and out. Many have since been repointed or rendered in cement and replastered in gypsum, which can trap water. Historic England recommends getting the diagnosis right, keeping gutters and downpipes clear, checking that ground levels have not crept up, and using lime render, plaster and mortar where cement has caused problems.

1. Fix the outside first: roofs, valleys, gutters, downpipes, hoppers and gullies.
2. Lower paths and beds that sit above the damp-proof course, and cut back render that bridges it.
3. Repoint and re-render with breathable lime where cement is holding water.
4. Heat and ventilate kitchens, bathrooms and cold rooms to control condensation.
5. Let walls dry and replaster in breathable materials, rather than sealing them.
6. Use injection or tanking only where the cause calls for it, such as a damp-proof course that has genuinely failed, or a room below ground level.

For damp below ground, where different rules apply, see our guide to basement and cellar damp: tanking, injected DPC or membrane.

Choosing who to instruct

Option	Independence	Points to check
Report by a damp treatment company	Sells the remedy it recommends	Surveyor's CSTDB or CSRT qualification; whether the lender accepts it
Independent PCA-qualified surveyor	Reports without doing the work	Listed on the PCA search tool; experience with solid-walled houses
RICS building surveyor experienced in damp	Reports without doing the work	Ask for an inspection to the 2022 joint position statement and a CV showing older-building experience

Checkatrade's cost guide, last updated in 2023, puts a damp and timber survey at about £200–£600. This is an indicative market range, not an Alstruct price, and the guide does not say whether VAT is included. A lender may only accept certain qualifications, so check before you instruct anyone.

How Alstruct helps

We are builders, not damp surveyors. Through our pre-purchase advice service we read your survey and any damp and timber report, look at the house with you, and price the repairs that deal with the cause, such as roof, gutter, ground level and lime plaster work, alongside any treatment that is genuinely needed. The fee is from £500 + VAT, credited in full if you appoint Alstruct for the works within six months.

Frequently Asked Questions

Sources

• RICS consumer guide: damp and mould
• RICS: Investigation of moisture and its effect on traditional buildings (joint position statement, 2022)
• RICS, Historic England and PCA: joint position statement (PDF)
• Property Care Association: rising damp explained
• Property Care Association: the development of specialist timber and damp surveying qualifications
• Historic England: understanding decay in an older home
• Historic England: essential tips for maintaining and repairing older homes
• RICS: Description of the RICS Home Survey Level 2 (survey only)
• Checkatrade: damp survey cost guide

This guide is general information, checked against the sources above on 13 November 2026. It is not legal or survey advice: ask your conveyancer and surveyor about your own purchase.