How much does damp proofing cost in the UK? (2026)
Verified UK damp proofing costs in 2026 by damp type (rising, penetrating, condensation) and treatment (DPC injection, tanking, replastering), plus survey fees, PCA-registered installers, the 20-year guarantees, and the scope gaps that catch homeowners out.
Damp proofing in the UK in 2026 costs £350 for treating a single wall up to £3,500 for a full-house damp proof course. A typical 3-bed semi with damp on one or two walls sits at £800 to £2,000 including a salt-retardant replaster after the chemical injection (Checkatrade, MyJobQuote). Diagnosis matters more than treatment: getting the type of damp wrong is the most common reason a UK damp job fails.
Quick answer
UK damp proofing cost in 2026: single wall DPC injection £350 to £1,200, full-house DPC £1,800 to £3,500, basement or cellar tanking £80 to £140 per m², penetrating damp treatment £150 to £500 per area, specialist damp survey £150 to £300. PCA- registered installers give a 20-year insurance-backed guarantee. Most injected walls need 4 to 6 weeks drying before redecoration.
How to read this guide#
Two kinds of figures appear below:
- Headline price ranges (DPC injection by scope, tanking per m², penetrating treatment, survey fees): cross-referenced against Checkatrade and MyJobQuote.
- Practical guidance (damp diagnosis, PCA registration, drying times, what the price should include, red flags): drawn from standard UK damp industry practice and the Property Care Association professional standards.
Headline ranges (verified)#
DPC injection by scope#
| Scope | Range |
|---|---|
| Single wall (typical 3 to 5m) | £350 – £1,200 |
| Two adjacent walls | £700 – £2,000 |
| Whole ground floor (small house) | £1,200 – £2,500 |
| Full-house DPC | £1,800 – £3,500 |
These figures cover the chemical injection itself, plus removal of the affected plaster up to 1m, drying time, and salt-retardant replastering up to 1m. They assume the cause is genuinely rising damp, not penetrating damp or condensation.
Tanking (cellars, basements, retaining walls)#
| Item | Range |
|---|---|
| Cementitious tanking | £80 – £140 per m² |
| Cavity drain membrane system | £100 – £180 per m² |
| Small cellar (10 m²) | £1,000 – £1,800 |
| Larger basement (30 m²) | £3,000 – £5,500 |
| Sump pump (where required) | £400 – £900 |
Penetrating damp#
| Treatment | Range |
|---|---|
| Re-pointing failed mortar joints | £25 – £45 per m² |
| Repairs to failed render (per affected area) | £150 – £500 |
| External waterproof coating (Storm-Dry or similar) | £8 – £18 per m² |
| Replacing failed lead flashing | £200 – £600 per area |
Survey and assessment#
| Item | Range |
|---|---|
| Damp company free assessment | £0 (part of quote visit) |
| Independent damp survey (PCA member) | £150 – £300 |
| Structural surveyor's damp report | £400 – £800 |
| Moisture meter and probe survey | included in above |
London and South-East uplift#
Damp proofing in London and the South-East runs roughly 15 to 25% above national, mostly on the labour side. A £1,800 full-house DPC nationally typically lands at £2,200 to £2,300 in inner London.
Practical guidance (industry standard)#
Three kinds of damp, three different treatments#
The single most important step is diagnosing which type of damp you have. The treatments are different and applying the wrong one wastes money and time:
- Rising damp: travels up from the ground through a failed or missing damp proof course. Treatment is chemical DPC injection (silane or siloxane fluid) or a physical DPC replacement, plus salt-retardant replastering. Cost: as above.
- Penetrating damp: comes in horizontally through external walls, usually because of failed render, missing pointing, blocked gutters, failed lead flashing, or cracked rainwater goods. Treatment is finding and fixing the source first, then allowing the wall to dry. Injection does nothing for this.
- Condensation damp: forms internally when warm moist air meets cold surfaces (usually external walls and corners). Treatment is ventilation upgrades (PIV unit, extractor fans, trickle vents) and improving wall insulation, not injection.
A surveyor or installer who recommends DPC injection without first ruling out penetrating and condensation is either inexperienced or selling the treatment they offer regardless of the diagnosis. PCA codes of practice require all three to be considered.
Why drying time matters#
After a DPC injection, the wall needs to dry from the inside out before being painted or wallpapered. The drying time depends on the wall thickness and the season:
- 9-inch solid wall, summer: 4 to 6 weeks
- 9-inch solid wall, winter: 6 to 10 weeks
- Thicker walls or basements: up to 12 weeks
Redecorating before the wall has dried traps moisture in the substrate. Paint blisters, wallpaper peels, and salt efflorescence breaks back through within 6 to 12 months. The homeowner judges the treatment to have failed when the real failure is the redecoration timing.
A fair quote sets out the expected drying period and recommends a breathable paint (mineral or lime-based emulsion) for the first coat. A quote silent on drying time is letting you set yourself up for a repaint.
PCA registration and the 20-year guarantee#
The Property Care Association is the UK industry body for damp, timber, and structural waterproofing specialists. PCA-registered companies meet training, competence, and insurance standards. Their work is backed by an insurance-backed guarantee (GPI, Guarantee Protection Insurance) for 20 years, which transfers with the property.
The certificate is what a buyer's solicitor or surveyor will ask for when the property is sold. A non-PCA installer may be £200 to £400 cheaper on a typical job but leaves no recourse if the treatment fails, and the missing certificate is a sale-conveyance problem later.
What a fair damp quote should cover#
A complete DPC injection quote should include:
- A diagnosis report identifying the damp as rising (not penetrating or condensation), with moisture readings.
- The damp proof course injection itself, with the fluid type named.
- Removal of affected plaster up to 1m above the floor.
- Drying period clearly stated (4 to 12 weeks depending on wall type and season).
- Salt-retardant render replastering up to 1m.
- A breathable first coat recommendation.
- PCA registration with the GPI guarantee number.
- 12-month workmanship guarantee on top of the GPI insurance.
- Removal and disposal of broken plaster and waste.
It often does not cover:
- Repairs to the source of penetrating damp (failed render, broken gutters, missing pointing) if these are the real cause.
- Redecoration after the drying period.
- Floor treatments where damp has tracked under floorboards.
- Ventilation upgrades for condensation issues identified during the survey.
- Removal and replacement of skirting boards.
- Replacement of damaged plaster above the 1m line if salt contamination has tracked higher.
A tanking job is different from a DPC#
Tanking applies to basements, cellars, retaining walls, and any structure with ground water pressure on the outside. It is not chemical injection; it is a continuous waterproof barrier (either cement-based tanking slurry or a cavity drain membrane system) on the inside of the wall. Costs are higher per m² because the system is more substantial and the works deeper.
A quote that confuses the two ("we will tank the wall by injection") is a misuse of terms and a sign the installer is not familiar with basement waterproofing.
Regional variation#
UK damp proofing costs vary by region, mostly on the labour side (injection fluid and plastering materials are nationally priced):
- Inner London: ~20 to 25% above national
- Outer London / South-East: ~10 to 15% above
- Midlands and East: close to national
- North of England, Wales: ~5 to 10% below
- Northern Ireland, rural Scotland: ~10 to 15% below
Red flags in damp quotes specifically#
Beyond standard quote red flags (covered separately), some are damp-specific:
No diagnosis written down. A quote that goes straight to "we recommend DPC injection" without identifying the type of damp and the moisture readings is selling the treatment, not the solution.
Not PCA-registered. No 20-year insurance-backed guarantee. The saving is small; the risk at resale is not.
Penetrating or condensation symptoms but DPC recommended. A common mis-sell. Cold corners, mould on the ceiling, or damp around windows is rarely rising damp. If the symptoms do not match the diagnosis, get a second opinion.
No drying time mentioned. Sets up a repaint within 12 months that the homeowner blames on the treatment.
No salt-retardant replaster included. Standard plaster lets the salt contamination break back through. Salt-retardant render is the standard finish after injection.
Free survey only if you sign on the day. A reputable surveyor gives the survey without a same-day commitment. Pressure to sign during the visit is a sales technique, not a diagnosis.
Quote does not name the injection fluid. Silane and siloxane fluids from established suppliers (Sovereign, Permagard, Triton) are the UK standard. "We use a damp-proofing chemical" with no name is leaving room to substitute.
No mention of the cause of penetrating damp, where penetrating damp is the real problem. Treating the inside without fixing the outside is a recurring cost.
Sequence of work on a DPC injection job#
- Survey and diagnosis. Moisture readings on the affected wall, salts test if relevant, confirmation that the damp is rising and not penetrating or condensation.
- Quote with treatment scope. Walls to be treated, fluid type, replaster scope, drying period.
- Plaster removal. Affected plaster removed to 1m above floor level. Disposal included.
- DPC injection. Holes drilled in the mortar joint above the floor; fluid injected to saturation.
- Drying period. 4 to 12 weeks depending on wall and season.
- Salt-retardant replaster. Specialist render applied to 1m, sometimes higher if salts have tracked.
- Handover and guarantee. GPI guarantee issued through PCA.
The homeowner does the redecoration after the drying period, with a breathable paint as the first coat.
Comparing your damp proofing quote#
The reliable way to know if a damp quote is fair is to check the diagnosis matches the symptoms, confirm the installer is PCA- registered, verify the drying period is stated, and check the per- wall or per-m² rate against the bands above. The easier way is to paste or upload your quote into Check the Quote, where we check every line against current UK rates, verify the PCA listing, and flag where the diagnosis and treatment do not match. Your first check is free. For related moisture-management trades, see the cavity wall insulation and rendering guides.
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Frequently asked questions
- How much does damp proofing cost in the UK in 2026?
- A full-house damp proof course (DPC) injection runs £1,800 to £3,500 in 2026 (Checkatrade, MyJobQuote). Treating a single wall is £350 to £1,200. Basement or cellar tanking is £80 to £140 per m². Penetrating damp treatment is £150 to £500 per affected area. A damp survey on its own is £150 to £300, usually credited back if the work is commissioned. London and the South-East run 15 to 25% above national.
- What is the difference between rising, penetrating, and condensation damp?
- Rising damp travels up from the ground through a failed or missing damp proof course; treatment is DPC injection or replacement. Penetrating damp comes in horizontally through external walls, usually because of failed render, pointing, or guttering; treatment is fixing the source first, then drying the wall. Condensation damp forms internally from moisture in the air meeting cold surfaces; treatment is ventilation and insulation, not injection. Mistaking condensation for rising damp is the most common UK damp diagnosis error.
- How much is a damp survey, and do I need one?
- A specialist damp survey costs £150 to £300 in 2026. Most reputable damp companies offer a free assessment as part of the quote, but a paid independent survey by a PCA-registered surveyor (one not selling the treatment) is worth the £200 if the cause of damp is unclear. Independent surveys catch the misdiagnoses where rising damp is recommended when condensation or a failed external is the real problem.
- Why is PCA certification important?
- The Property Care Association is the UK industry body for damp, timber, and structural waterproofing. PCA-registered companies meet competence and insurance standards and their work comes with an insurance-backed 20-year guarantee through GPI (Guarantee Protection Insurance). The certificate transfers with the property and is the thing buyers and surveyors look for. A non-PCA quote may be cheaper but leaves no recourse if the treatment fails.
- How long does damp proofing take?
- Treating a single wall takes 1 to 2 days for the injection and replastering. A full house DPC takes 3 to 5 days. Cellar or basement tanking on a small space is 5 to 10 days. Drying time before redecoration is 4 to 6 weeks for an injected wall (the wall needs to dry from the inside out before being painted, or paint traps moisture). Walking back into a redecorated wall 2 weeks after treatment is the most common reason a job is judged to have failed when it hasn't.
- What is normally left out of a damp proofing quote?
- Common gaps: removal and disposal of damaged plaster (sometimes included, sometimes not), replastering with salt-retardant render (essential after DPC injection), redecoration after drying out, repairs to the source of penetrating damp (failed render, broken gutters, missing pointing) which often need a separate trade, ventilation works (extractor fans, air bricks) for condensation jobs, and floor treatments where damp has tracked under the floorboards.