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What Is a Damp and Timber Report?
Updated 5 November 2026. Reviewed by Michael Young, Head Contractor at Advanced Damp (CSSW and FODCS).
Key Takeaways
- A damp and timber report is a specialist inspection of a property for damp, wood rot and woodworm, with a written diagnosis of the cause and recommended treatment.
- It is most often requested when a mortgage valuation or homebuyer survey flags possible damp or timber defects.
- A good report explains why the damp is there, not just where it is. Moisture meter readings alone are not a diagnosis.
- Look for surveyors with the CSRT qualification (Certificated Surveyor in Remedial Treatment), and ask whether the report is independent or comes from a company that will also quote for the work.
- There is no legal requirement to get one, but lenders can make a mortgage offer conditional on it.
What is a damp and timber report?
A damp and timber report is a focused inspection carried out by a specialist surveyor. Where a general homebuyer survey notes that damp or timber problems may be present, this report goes further. The surveyor investigates the walls, floors and accessible timbers, works out what is causing any damp, identifies any rot or wood boring insect activity, and sets out what needs to be done. It is sometimes called a damp and timber survey or a specialist damp report.
When you might need one
- A lender has asked for one. Mortgage valuers often recommend a specialist damp and timber report if they see signs of damp or high meter readings, and the lender may hold back the offer until it is done.
- Your homebuyer survey flagged damp. General surveyors usually recommend further investigation by a specialist rather than diagnosing damp themselves.
- You are selling. Getting a report early can help you deal with issues before a buyer’s survey raises them.
- You can see a problem. Tide marks, mould, crumbling plaster, soft skirting boards, a musty smell or small holes in timber are all worth investigating.
- Previous treatment has failed. A report can establish whether the original diagnosis was right and whether any guarantee applies.
What the surveyor inspects
- Internal walls. Moisture patterns, salts, tide marks, blown plaster and staining, particularly at low level and around chimney breasts.
- External walls. Pointing, render, the damp proof course line, ground levels, paths and anything bridging the DPC.
- Rainwater goods. Gutters, downpipes, flashings and drainage that might be feeding water into the structure.
- Floors. Suspended timber floors, joist ends, wall plates and the condition of subfloor ventilation where access allows.
- Roof timbers and lofts. Signs of woodworm, rot and roof leaks where the loft is accessible.
- Ventilation and condensation. Extract fans, trickle vents, humidity and the pattern of any mould.
The surveyor can only report on areas they can see and reach. Fitted floor coverings, stored items and furniture limit what can be inspected, and a good report says clearly what was not accessible.
How surveyors test for damp and timber defects
A moisture meter is a useful screening tool, but it is not a diagnosis. Electrical meters are calibrated for timber, and on plaster and masonry they can give high readings for reasons that have nothing to do with damp, such as salts, foil backed paper or carbon in old plaster. A competent surveyor uses meter readings to map a pattern and then confirms the cause with other evidence.
- Moisture meter mapping to show the height, spread and pattern of damp
- Salt analysis of plaster samples, since chlorides and nitrates point to ground moisture
- Drilled masonry samples, tested with a carbide meter or by weighing and drying, to measure actual moisture content in the wall
- Hygrometer readings of air temperature and humidity to assess condensation risk
- Thermal imaging to show cold spots and hidden leaks
- Timber probing to find softening, decay and the exit holes left by wood boring insects
Our damp survey guide explains these methods in more detail.
What the report should tell you
A useful report is clear about cause, not just symptoms. Expect it to include:
- The type of damp found, such as rising, penetrating or condensation, and the evidence for that conclusion
- The location and extent of any damp, rot or woodworm, often with photographs and a plan
- Whether any wood boring insect activity is active or historic
- The repairs needed to deal with the cause, such as gutter repairs, repointing or ventilation improvements
- Any remedial treatment recommended, such as a damp proof course, replastering or timber treatment
- Areas that could not be inspected and any further investigation needed
If a report recommends a damp proof course for every damp wall without explaining why, or does not mention outside defects at all, ask questions before agreeing to the work.
Damp and timber problems that often go together
Damp and timber defects are linked. Timber in contact with damp masonry is at risk of wet rot and, in poorly ventilated spaces, dry rot. Woodworm also prefers damp timber. That is why the two are inspected together. Common findings include joist ends sitting in wet walls, wall plates decayed behind skirting boards, rot in timber lintels and old woodworm in floorboards and roof timbers that may or may not still be active.
Independent or contractor report?
Some damp and timber reports are carried out by independent surveyors who only diagnose. Others come from specialist contractors who can also carry out the work. Both can be good, but you should know which you are getting. Whoever carries it out, look for:
- The CSRT qualification, and the CSSW qualification if basements are involved
- A clear written diagnosis with evidence, not a quote presented as a report
- Recommendations that start with fixing the cause, not only with chemical treatment
- Membership of a recognised trade body, and a long-term written guarantee on any work carried out
What to do after you receive the report
- Read the cause and evidence sections first, not just the list of works
- Share the report with your lender or conveyancer if it was requested as part of a purchase
- Prioritise outside repairs that stop water getting in, since treatment without them rarely lasts
- Get the remedial work specified clearly enough to compare quotes like for like
- Keep the report and any guarantee paperwork, as future buyers and lenders will ask for them
When to book a damp and timber survey
Book a survey if your lender or homebuyer survey has flagged damp or timber defects, if you are buying a period property, or if you can see damp, rot or woodworm and want to know what is causing it. You can book a survey online and we usually respond the same day during working hours.
Frequently asked questions
What does a damp and timber report include?
It covers damp in walls and floors, wood rot and woodworm in accessible timbers, the causes behind any problems found, and the repairs or treatment recommended. A good report includes photographs, readings and a clear list of areas that could not be inspected.
Is a damp and timber report a legal requirement?
No. There is no legal requirement, but mortgage lenders can make an offer conditional on a specialist report if their valuer has flagged damp or timber defects.
How long does a damp and timber survey take?
It depends on the size of the property, how much can be accessed and whether samples need testing. A flat with one problem wall takes far less time than a full inspection of a period house with lofts and cellars, so ask the surveyor when booking how long to allow and when the written report will follow.
Are moisture meter readings enough to diagnose damp?
No. Meters are calibrated for timber and can give misleading readings on plaster and masonry. They show where to look, and the cause should be confirmed with other tests such as salt analysis or drilled samples.
What qualifications should a damp and timber surveyor have?
Look for the CSRT qualification (Certificated Surveyor in Remedial Treatment). For basements and below ground waterproofing, the CSSW qualification is also relevant.
What happens if the report finds woodworm?
The surveyor should say whether the activity is active or historic. Historic woodworm may need no treatment, while active infestations usually need treatment and any weakened timbers repairing or replacing.
Reviewed by Michael Young, Head Contractor at Advanced Damp (CSSW and FODCS). Last reviewed November 2026.
Related Case Studies
Our recent work includes loft timbers, Edlesborough LU6; cellar, Berkhamsted HP4 and chimney breast, Oxford OX2. Each case study sets out what the survey found and how the problem was fixed.
Loft timbers, Edlesborough LU6
Common furniture beetle signs, likely historic, timbers sound and dry. Spray treatment and better ventilation.
Read the case study →
Cellar, Berkhamsted HP4
Failed cellar tanking and a decayed lintel at 40% WME. Type C waterproofing, sump pump and ventilation.
Read the case study →
Chimney breast, Oxford OX2
Salt staining on a chimney breast was treated with a damp proof course and salt resistant render, with window and gutter gaps sealed outside.
Read the case study →
Sam Fitzgerald is the founder of Advanced Damp and a working damp and structural waterproofing surveyor diagnosing and treating moisture problems in residential and commercial properties across London and the South East. He is FODCS certified (a Federation of Damp Certified Surveyor) and a member of the Federation of Damp. His hands-on work covers rising damp, penetrating damp, condensation, basement waterproofing to BS 8102, and thermal imaging surveys, and he has personally completed over 400 damp surveys across properties of every type and age. Everything he writes draws directly from jobs he has carried out. He does not write about treatments, products or causes he has not dealt with first-hand in the field.
