Damp and mould: find the cause before anyone quotes a fix.

Quick answer: damp and mould in a home usually has one of three causes: condensation, rising damp or penetrating damp. Each needs different work, so the first step is a survey that finds the source. We don’t publish prices, because the survey decides the job and we found no official or independent source for damp survey or treatment costs. Damp work carries standard-rate VAT. If you rent from a council or housing association in England, Awaab’s Law makes the repair your landlord’s job, with legal time limits.

Three kinds of damp, three different fixes

• Condensation. Moisture from everyday cooking, washing, drying clothes and breathing settles on cold surfaces such as windows and outside walls. It is where black mould usually grows.
• Rising damp. Moisture from the ground drawn up the base of a wall.
• Penetrating damp. Water getting in from outside, through walls, roofs, gutters or window frames.

In England in 2024, 5% of homes (1.4 million) had a damp problem: serious condensation in 3%, penetrating damp in 2% and rising damp in 1%. Private rented homes were the most affected, at 10%, against 7% of social rented and 4% of owner-occupied homes. Far more households, 30%, reported some condensation, damp or mould (English Housing Survey 2024 to 2025).

Why the survey comes before the quote

The Property Care Association (PCA), the trade body for damp specialists, says it is important that the source of the dampness is investigated and established before any damp control or treatment is considered, and that misdiagnosis of a damp problem “is not uncommon” (PCA damp proofing advice). Because the three kinds of damp need different work, a fix chosen before the cause is known may leave the cause in place.

Ask for the diagnosis in writing. A PCA contractor member can survey the home, back its diagnosis with a written survey report, and quote for the work that follows. With a report behind each quote, you can see whether two companies found the same problem.

Who can survey your home

The PCA lists four kinds of member (PCA member types):

• Contractor: surveys, investigates with a written survey report, and quotes for the repair.
• PCA Independent Surveyor: has no commercial link with anyone who profits from building preservation work.
• PCA Freelance Surveyor: has a declared commercial link.
• Consultant: inspects and diagnoses, but does not quote for repairs or carry them out.

For rising damp, the PCA recommends a surveyor who is trained, experienced and qualified with the CSTDB (PCA rising damp advice). All PCA members are audited and checked regularly, the PCA offers a mediation service between consumers and members, and its contracting companies are registered with TrustMark. Under the PCA Promise, if a PCA damp contractor goes out of business before the work is finished, another PCA contractor completes it to the original specification at no extra cost (why choose a PCA member). Find members by service and type in the PCA directory, or check a company with the PCA member search.

Ventilation options for condensation

Condensation comes from moisture with nowhere to go, so ventilation is often part of the answer. The main options are extractor fans in kitchens and bathrooms, positive input ventilation (PIV), a unit that supplies filtered air to the home, and mechanical ventilation with heat recovery (MVHR), which ventilates the whole home and recovers heat from the outgoing air. Our guides cover each: PIV units, MVHR systems, and how to reduce condensation and damp while keeping your home warm.

If damp or mould appeared after insulation was fitted, read condensation, damp and mould after insulation.

What it costs, and the VAT

We don’t publish prices for damp work. We found no official or independent source for damp survey or treatment costs, and the price depends on what the survey finds. Compare quotes on the diagnosis and the written report behind them, not only the total.

Damp surveys, damp-proofing, mould treatment and ventilation such as PIV, MVHR and extractor fans are not on HMRC’s list of energy-saving materials, so standard-rate VAT applies. Insulation or draught-stripping fitted in the same job can still be zero-rated until 31 March 2027 (HMRC VAT Notice 708/6).

Renting? Your landlord should fix it

Council and housing association tenants in England are covered by Awaab’s Law, in force since 27 October 2025. When damp and mould poses a significant risk, the landlord must investigate within 10 working days of becoming aware of it, send you a written summary within 3 working days of the investigation ending, and make the home safe within 5 working days of it. Emergency hazards must be made safe within 24 hours. If the work cannot be done in time, the landlord must arrange suitable alternative accommodation at no cost to you. Read Awaab’s Law explained, and in the North West, how to report damp to the largest landlords in Greater Manchester and Lancashire.

Report it through your landlord’s official phone line, email or online system, and keep a record of what you reported, when, how and to whom (GOV.UK guidance for tenants). Our damp and mould letter tool writes the report for you.

Private renters in England should contact the landlord and carry on paying rent while waiting. If repairs are not done, contact the environmental health department at your council, which can assess the home for hazards (GOV.UK: private renting repairs). Extending Awaab’s Law to private renting is planned, with no date set.

Elsewhere in the UK: in Scotland, Awaab’s Law covers social tenants and most private tenants from 6 October 2026 (Scottish Government guidance). In Wales, the landlord must keep the home fit to live in, and damp and mould is one of the matters that count (Welsh Government guidance). In Northern Ireland, a privately rented home must be free from damp, and the council’s environmental health officer can act if the landlord does not (nidirect).

Last reviewed: 30 September 2026. Facts are checked against GOV.UK, HMRC and the Property Care Association. We do not publish prices for this work: the survey sets them.