Cost guides › Damp proofing
United Kingdom
How much does damp proofing cost?
Treating rising damp along 20 m of wall with a chemical damp-proof course, new plaster and redecoration typically costs £2,500 including VAT, with most quotes between £1,950 and £3,250. Injection and replastering alone is about £2,100; with an independent damp survey first and a full renovating-plaster system it is around £2,950. If the damp comes through the wall rather than up it, or you want a cellar tanked, pick that treatment in the calculator.
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mid-range, typicalCost by region
| Location | Basic | Mid-range | Premium |
|---|---|---|---|
| London | £2,250 | £2,700 | £3,150 |
| Scotland | £2,100 | £2,550 | £3,000 |
| East | £2,050 | £2,500 | £2,900 |
| North West | £2,050 | £2,500 | £2,900 |
| South East | £2,100 | £2,500 | £2,950 |
| East Midlands | £2,050 | £2,450 | £2,850 |
| North East | £2,050 | £2,450 | £2,850 |
| South West | £2,050 | £2,450 | £2,900 |
| Wales | £2,050 | £2,450 | £2,850 |
| West Midlands | £2,050 | £2,450 | £2,900 |
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| Yorkshire and The Humber | £2,000 | £2,450 | £2,850 |
What's included
Mid-range
- Drilling the mortar course just above ground level at about 12 cm centres
- Injecting silicone damp-proofing cream into every hole
- Hacking off salt-contaminated plaster to about 1.2 m
- Removing the plaster rubble from site
- Replastering with a salt-resistant sand and cement render and finishing coat
- Taking off and refitting or renewing the skirting boards
- Mist coat and two coats of breathable paint on the new plaster
What affects the cost
Getting the diagnosis right
A lot of damp sold as rising damp is actually condensation, a leaking gutter, a bridged cavity or high ground outside. Injection only helps with genuine rising damp, so a proper survey with the cause identified is worth more than any guarantee.
Plaster, not just the injection
The injected course itself is a small part of the bill. Most of the cost is hacking off the old plaster, which is full of hygroscopic salts, and replastering with a render that holds them back.
Wall type
Solid brick walls with a continuous mortar bed are straightforward. Thick rubble stone walls are harder to inject evenly, and old lime-built houses often do better with breathable lime plaster and better drainage than with cement render.
Ground levels and drainage
Soil, paving or a raised patio above the old damp-proof course will keep pushing water into the wall. Lowering the ground or adding a drainage channel outside is often part of a lasting fix.
Penetrating damp
Damp that shows high up or after rain usually comes through failed pointing, cracked render or faulty gutters. Repointing and fixing the rainwater goods cost more per metre but cure the actual cause.
Cellars
A cellar below ground level cannot be dried with an injected course. It needs tanking with a cementitious slurry or a cavity drain membrane, priced over the full wall height.
How to save
- Fix gutters, downpipes and high ground levels first; sometimes that alone cures the damp.
- Pay for an independent survey rather than relying on a free one from a company selling treatments.
- Let the walls dry out before decorating, and use breathable paint on new plaster.
- Have all affected walls treated in one visit to share the set-up and plastering costs.
Grants, tax and rules
VAT
Our figures include 20% VAT.
Frequently asked questions
How much does damp proofing cost in the UK?
For 20 m of wall, a chemical damp-proof course with replastering and redecoration costs around £2,500 including VAT. Injection and plaster alone is about £2,100.
How much does damp proofing cost per metre?
Divide the total by the length of wall treated: for 20 m the typical price is £2,500, including hacking off, new plaster and decoration. The injection itself is only part of that; replastering is the bigger share.
Does a damp-proof course need replastering?
Almost always. The old plaster is loaded with salts drawn up from the ground and will stay damp and stained even after the new course works, so it is hacked off to about a metre and renewed with a salt-resistant render.
How long does it take for walls to dry after damp proofing?
As a rough guide a solid wall dries about 25 mm a month, so a thick wall can take many months. Use breathable paint and avoid wallpaper or vinyl finishes until the wall is dry.
Is it rising damp or condensation?
Rising damp leaves a tide mark up to about a metre with salts and crumbling plaster at the base of the wall. Condensation shows as black mould in corners, behind furniture and on cold outside walls, and is fixed with ventilation and heating rather than injection.
How this estimate is calculated
Work hours: 36.3 · Labour: £1,273 · Materials: £823
Sources: ONS Annual Survey of Hours and Earnings, tables 14 and 15; Regione Toscana, Prezzario dei Lavori 2026 (CC BY 4.0); ECB exchange rates; market check: 20 m of wall, chemical DPC injection with replastering, incl. VAT. Checkatrade damp proofing cost (updated Jun 2026: injection £60-200/m, avg £100/m; injection job £1,000-3,000; tanking £100-200/m2); MyBuilder damp proofing cost guide (21 Aug 2026: rising damp ~£2,500, penetrating ~£1,200, basement ~£6,500) and damp proof course guide (21 Aug 2026: injection £40-60/m); Checkatrade repointing cost (Jun 2026: £50-60/m2).
Last reviewed 26 September 2026 · How we calculate costs · Editorial policy