What Does Damp Treatment Cost?
Quick Answer
DPC injection £40–£90 per metre. Whole-house rising damp treatment £800–£5,200
Guide prices from published 2026 UK cost guides, not quotes. Book an independent damp survey (£150–£600) before committing to anything: misdiagnosis is the most expensive mistake in damp work
Damp Treatment Costs by Type (2026 UK)
The table below collates the major published 2025–2026 UK cost guides (Checkatrade, MyBuilder, MyJobQuote) and specialist contractors’ published price bands. Where the guides disagree, the range shows the full spread rather than a false average. Every figure is a national guide price: get an independent survey and itemised local quotes before budgeting.
| Treatment | Guide price | Notes |
|---|---|---|
| Independent damp survey | £150–£600 | Priced by property size, not damp type: about £200 for a 2-bed flat, £400 for a 3-bed house, £600 for a 4-bed detached |
| Chemical DPC injection | £40–£90 per metre | Drilling and injection only; some guides run to £120 per metre. Replastering is always priced separately |
| Chemical DPC, whole house | £800–£5,200 | Full spread across guides; most jobs land £1,000–£3,000. Guides differ on whether whole-house figures include replastering, so confirm what any quote covers |
| Physical DPC or membrane replacement | £1,500–£7,500 | Guides disagree widely; cutting in a new physical course is the most disruptive and costly option |
| Replastering after treatment | £450–£800 per room | The usual hidden cost: salt-contaminated plaster is hacked off and renewed. Small single-wall patches from about £100 |
| Tanking slurry (cementitious) | £40–£100 per m² | Cellars and below-ground walls; whole-cellar tanking projects typically £2,800–£6,700 |
| Cavity drain membrane | £80–£150 per m² | Installed; sump and pump add roughly £1,000–£2,000 |
| PIV unit (condensation) | £400–£1,200 | Typically about £900 supplied and installed; heated units cost more |
| Extractor fan, supplied and fitted | £140–£420 | Like-for-like swap at the bottom of the range; new install with wiring and ducting at the top |
| Repointing (penetrating damp) | £25–£60 per m² | Cement mortar; lime mortar for older homes £60–£80 per m². Scaffold extra |
| Re-rendering (penetrating damp) | £30–£80 per m² | A full re-render of a 3-bed house runs £8,000–£15,000 including scaffold |
Rising Damp Treatment Cost by House Size
MyJobQuote’s January 2026 rising damp guide prices whole-property treatment (supply and labour, before replastering) like this:
| House type | Guide range (treatment only) |
|---|---|
| Terraced house | £250–£1,020 |
| Semi-detached house | £475–£2,350 |
| Detached house | £690–£5,200 |
Other guides broadly agree: Checkatrade puts injection damp proofing at £1,000–£3,000 with around £2,000 typical for a semi, and MyBuilder quotes £800–£1,500 for a standard three or four bed semi-detached. The spread is real, so treat anything inside these ranges as plausible and compare itemised quotes. Add replastering (£450–£800 per affected room) to whichever treatment figure you use: it is routinely the largest single line on the final bill. Work out how many metres of wall actually need treating with our rising damp calculator.
Condensation: the Cheapest Damp to Fix
Most damp in UK homes is condensation, and it is also the cheapest to put right. A new extractor fan costs £140–£420 supplied and fitted, and a positive input ventilation (PIV) unit around £900 supplied and installed (£400–£1,200 across guides). Improved heating patterns and moisture habits cost nothing. Size the ventilation you need with the condensation ventilation calculator or the PIV unit calculator, and scope any mould clean-up with the mould treatment calculator.
Penetrating Damp Repairs
Penetrating damp is priced by the defect that lets water in, not per metre of wall. Repointing runs £25–£60 per m² (lime mortar £60–£80), re-rendering £30–£80 per m², and simple fixes such as clearing gutters or resealing around frames cost far less than any damp-proofing contract. MyJobQuote’s 2026 penetrating damp guide puts most jobs between £300 and £1,500, rising to £1,000–£5,000 or more where external repairs are extensive. Where a failed cavity tray is the culprit, one published guide budgets £200–£300 to supply and fit a tray in a metre of wall; longer runs scale with length and access, so treat that one as indicative only. For below-ground walls, compare tanking against a cavity drain membrane using the per-m² rates in the table.
Get a Survey First: Rising vs Penetrating
Surveys are priced by property size rather than by damp type, because a competent surveyor diagnoses rising damp, penetrating damp and condensation in the same visit: about £200 for a 2-bed flat, £400 for a 3-bed house and £600 for a 4-bed detached, with £150–£600 the spread across guides. A combined damp and timber survey sits in the same £200–£600 band. Pay for independence: a free survey from a company that sells damp-proofing is a sales visit, not a diagnosis. RICS, Historic England and the Property Care Association published a joint position statement in 2022 on investigating moisture in older buildings precisely because misdiagnosis is so widespread. Estimate survey scope with our damp survey calculator.
What Affects the Price
- Diagnosis: treating the wrong damp type is the biggest waste of money in this trade. Survey first
- Metres of affected wall: injection is priced per metre, so a single wall costs a fraction of a whole house
- Wall thickness and construction: 9-inch solid brick needs deeper drilling than a single skin; rubble-filled stone walls may not suit injection at all
- Replastering scope: £450–£800 per room, plus skirting boards and redecoration on top
- Access: scaffold for external repointing or render adds roughly £600–£1,500
- Below-ground work: tanking and membrane systems are priced per m² and rise sharply once sumps and pumps are needed
- Guarantees: chemical DPC work from PCA member firms normally carries a 20–30 year guarantee; check it is insurance-backed so it survives the contractor ceasing to trade
London and the South East
Every cost guide we checked prices London and the South East above the national figures in these tables: MyJobQuote adds £30–£70 per day to labour rates, Advanced Damp’s published London bands run £60–£100 per m² for tanking slurry against £40–£80 nationally, and repointing guides quote £50–£80 per m² in the South East against a £40–£60 UK average. As a rule of thumb, allow 10–30% over the table figures in London and the South East.
Signs of Each Damp Type
- Rising damp: tide marks up to ~1m high, salt deposits, peeling wallpaper at skirting level
- Penetrating damp: damp patches that worsen in rain, often around windows or on external walls
- Condensation: black mould in corners, on cold walls, and around windows. Worst in winter
Important Notes
- Get a proper independent damp survey before committing to treatment: misdiagnosis is common
- True rising damp is rarer than many damp-proofing companies suggest
- Most “rising damp” is actually condensation or penetrating damp
- Chemical DPC injection typically comes with a 20–30 year guarantee; insist on an insurance-backed one
- All figures here are guide prices, not quotes: costs depend on your walls, access and region, so get at least three itemised quotes
Figures cross-checked against published UK cost guides July 2026. Last updated: July 2026