During a damp survey, an RICS Chartered Surveyor inspects the outside and inside of the property, takes moisture and environmental readings, carries out targeted tests where needed, and then produces a written report that explains the cause of the damp or mould and what should be done about it. This guide explains what happens during a damp survey at Lansdown Associates, step by step, so you know what to expect and how to prepare.
Before the visit
When you book, we ask about the property and the problem: where the damp or mould is, how long it has been present, whether it changes with the weather or the seasons, and whether any treatment or repairs have already been carried out. If there are previous reports, contractor quotations, tenant complaints or photographs, please send them. They help us plan the inspection and decide which tests are likely to be needed.
For rented homes we will also ask about access arrangements and who will be present. Social landlords working to Awaab’s Law timescales should tell us the date they became aware of the hazard, so we can plan accordingly.
Step-by-step: the survey on site
1. Discussion with the occupier
We start by talking to whoever lives in or uses the property. Occupiers often know when the problem is worst, which rooms are affected, how the home is heated and ventilated, and whether there have been leaks. This information shapes the rest of the inspection.
2. External inspection
Many damp problems start outside. We inspect, from ground level and other safe vantage points:
- Roof coverings, chimneys and flashings where visible
- Gutters, downpipes and drainage
- Walls, pointing, render and any cracking
- Window and door openings, sills and seals
- External ground and path levels relative to internal floors and any damp-proof course
- Sub-floor ventilation openings
Where roof or gutter defects may be letting water in and cannot be seen safely from the ground, the roof, chimneys and parapets can also be inspected by drone.
3. Internal inspection
We then inspect the affected rooms and the wider property, recording the location, extent and pattern of damp and mould. We look at wall and ceiling finishes, floors, skirtings and joinery, and at heating, ventilation, extractor fans, trickle vents and signs of how the home is used, such as clothes drying indoors.
4. Moisture meter survey
A moisture meter is used to map the pattern of readings across walls and floors. The pattern is often more telling than the numbers: readings that fade out at a consistent height suggest one cause, while readings concentrated around a window or below a bathroom suggest another. Because meters can be misled by salts and some materials, we treat them as a screening tool, not proof.
5. Environmental readings
We record ambient temperature, relative humidity and dew point, and compare them with surface temperatures. This tells us whether conditions favour condensation and mould. Our guide to relative humidity and condensation explains how these readings fit together.
6. Thermal imaging
A thermal imaging camera shows surface temperature differences. It helps identify cold spots such as thermal bridges and missing insulation, where condensation is likely to form, and can help trace hidden leaks and air leakage.
7. Airflow analysis
Where ventilation is part of the picture, we check airflow at extractor fans and vents to see whether moisture produced in kitchens and bathrooms is actually being removed.
8. Calcium carbide testing and salt analysis
Where we need to know whether a wall is genuinely wet, or only giving high readings because of salts at the surface, we take small drilled samples of masonry or plaster for calcium carbide testing, which measures moisture content. Salt analysis checks for hygroscopic salts that can draw moisture from the air and give misleading readings. These tests involve small, neat drill holes, and we will explain where and why before we take samples. Read more in our guide to the calcium carbide test.
9. Photographs and records
Throughout the visit we photograph defects, readings and relevant features so that the report is clear and the evidence can be relied upon later.
Not every survey needs every test. We choose the methods that will answer the question for your property, and the report explains the reasoning.
Tools used during a damp and mould survey
| Tool or test | What it tells us |
|---|---|
| Moisture meter | The pattern and distribution of surface moisture readings (screening only) |
| Thermal imaging camera | Cold surfaces, thermal bridges, missing insulation, possible leaks |
| Temperature and humidity readings | Ambient temperature, relative humidity and dew point, and the risk of condensation |
| Airflow analysis | Whether extract fans and vents are removing moisture effectively |
| Calcium carbide test | The moisture content of masonry or plaster samples |
| Salt analysis | Whether hygroscopic salts are present and may be affecting readings |
| Drone inspection (where needed) | The condition of roofs, chimneys, parapets and gutters that cannot be seen safely from the ground |
What the report contains
After the visit you receive a written report prepared by the surveyor. It includes:
- A summary of findings in plain English
- A description of the property and the areas inspected
- Photographs and test results
- The type or types of damp identified, such as condensation, penetrating damp or rising damp (see our guide to the types of damp)
- The likely causes, including building defects, maintenance issues, design factors and how the home is used
- A risk rating so you can see how urgent each issue is
- Prioritised recommendations for remedial work
- For landlords, advice on urgency with reference to legal obligations, including Awaab’s Law timescales for social landlords where relevant
Reports are written so they can be shared with tenants, contractors, housing officers, lenders or solicitors. We normally issue the report within 5 to 7 working days of the inspection.
How to prepare for a damp survey
A little preparation helps the surveyor get accurate results:
- Clear access to affected walls, window reveals and corners. Move furniture away from external walls if you can.
- Allow access to the loft, under-stairs cupboard, kitchen and bathroom, and any cellar or sub-floor hatch.
- Do not redecorate or clean off mould immediately before the visit. The surveyor needs to see the problem as it is.
- Avoid running a dehumidifier or opening every window just before the visit, as this can mask normal conditions. Live in the property as you normally would.
- Gather documents: previous damp reports, guarantees for past treatment, repair records, tenant reports and your own photographs.
- Tell us about safety issues such as fragile ceilings, pets or vulnerable occupiers.
What happens after the survey
Remedial work
The report gives you a prioritised plan. Some items are simple maintenance, such as clearing gutters or repairing an extractor fan. Others may need a builder, roofer or specialist. Because Lansdown Associates does not sell damp-proofing products or carry out repairs, our recommendations are independent, and you are free to use any competent contractor.
Verification revisit
Once work is complete, we can carry out a follow-up verification inspection to check that the repairs have been done satisfactorily and that the problem has been resolved. Walls can take time to dry after a water source is stopped, so the timing of this visit matters. We will advise on when it is sensible to return.
Disputes and claims
If damp is the subject of a disrepair claim or dispute, we can also provide independent evidence. See our damp and mould expert witness service.
Frequently asked questions
How long does a damp survey take?
For most standard property types, the inspection takes around one to two hours on site, depending on the size and condition of the property, how many areas are affected and the tests needed. We will give you an indication when you book.
Will the survey damage my walls?
Most of the inspection is non-invasive. Calcium carbide testing and salt analysis require small drill holes to collect samples. We will explain where samples are needed before taking them.
Do I need to be at home?
Someone needs to provide access. It helps if the occupier is present at the start, to tell us when and where the problem appears.
Is a damp survey different from a mould survey?
At Lansdown Associates they are the same inspection. Mould is almost always a symptom of excess moisture, so our damp and mould surveys investigate both the mould and the moisture that is causing it.
Book a damp and mould survey
If you would like an RICS Chartered Surveyor to investigate damp or mould in your property, find out more about our damp and mould surveys. Homeowners and buyers wanting a second opinion can also book an independent damp survey, and housing providers can read about our damp and mould surveys for housing associations.
For a free quotation, call 0151 374 0905 or email office@lansdownassociates.co.uk (Monday to Friday, 09:00 to 17:00). We usually respond within one working day.
