How Much Does Damp Proofing Cost in 2026
Updated 4 November 2026. Reviewed by Michael Young, Head Contractor at Advanced Damp (CSSW and FODCS).
Key Takeaways
- The cost of damp proofing depends far more on the cause of the damp than on the size of the house.
- A chemical DPC typically costs £70 to £120 per linear metre in London, with replastering usually the larger part of the bill.
- Penetrating damp repairs range from small repointing jobs to major roof or parapet work.
- Comparing quotes only works if each one is based on the same diagnosis and the same scope of work.
- The cheapest job is the right job: one that fixes the actual cause, backed by a written report and a long-term written guarantee.
Ask five companies how much damp proofing costs and you may get five very different answers. That is not always because one is cheap and another is expensive. Often they are pricing different jobs, because each has reached a different view of what is causing the damp. This guide sets out typical prices for the main treatments, explains what pushes a price up or down, and shows how to compare quotes properly.
Typical damp proofing costs in 2026
The figures below are typical ranges for London and the South East. Every property is different, so treat them as a guide rather than a quote.
- Chemical DPC injection for rising damp: £70 to £120 per linear metre in London, slightly less elsewhere.
- Removing and replastering salt affected walls: typically £50 to £80 per square metre, using a salt resistant render and finish.
- Rising damp treatment for a two bedroom terraced house in London: often £1,500 to £2,500 all in, including replastering.
- Penetrating damp repairs: from around £300 for straightforward repointing to £6,500 or more where a failed flat roof or parapet wall is feeding water into the building.
- Basement waterproofing in London: typically from £7,000, and can exceed £20,000 for a full cavity drain membrane system on a larger property.
Condensation is usually the least expensive cause to fix, because the work is about ventilation, extraction and heating rather than wall treatment. See our condensation service for the options.
Why the diagnosis decides the price
Damp proofing is not one product. Rising damp, penetrating damp and condensation each need completely different work, and many homes have more than one at once. If a DPC is injected into a wall that is actually damp from a leaking downpipe, the money is wasted and the damp comes back. If condensation is treated as rising damp, the homeowner pays for injection and replastering that were never needed.
That is why every quote should start from a clear diagnosis that names the cause and explains the evidence. Our guide to what a damp survey includes explains what a proper inspection looks like.
What affects the cost of damp proofing
- Length of wall affected: DPC work is priced by the metre, so more affected wall means a higher price.
- Replastering: how much plaster is contaminated with salts, and how high it has to come off, often decides the final bill.
- Wall type and thickness: solid walls, rubble walls and thick party walls take longer to drill and treat.
- Access and preparation: fitted kitchens, radiators, skirting, sockets and flooring may need removing and refitting.
- External repairs: lowering ground levels, repointing, render or gutter repairs can be needed before internal work starts.
- Making good and decorating: some quotes include skirting, sockets and decorating, others stop at plaster.
- Location: London prices are usually higher than the national average.
How to compare damp proofing quotes
Put quotes side by side and check each one against the same questions:
- Does it name the cause of the damp, with evidence, in a written report?
- Does it state exactly which walls, how many metres and how much plastering are included?
- What render and plaster system will be used, and is it salt resistant?
- Is making good included, such as skirting, sockets and decorating?
- Is there a long-term written guarantee, and is it insurance backed?
- Is the company accredited and insured, and are the surveyors qualified, for example CSSW and CSRT trained?
A low quote that leaves out replastering, or a high quote that includes work the wall does not need, can both cost you more in the end.
Red flags to watch for
- Treatment recommended on the strength of a single moisture meter reading.
- No written report, or a report that does not explain the cause.
- Pressure to sign on the day, or prices that drop sharply if you agree immediately.
- Rising damp diagnosed on upper floors, which is not possible.
- No mention of external defects such as gutters, pointing or ground levels.
Spreading the cost
If the work is larger than expected, paying in instalments may help. We offer finance options through a regulated partner, subject to status. See our finance options page for details.
Rising damp treatment costs explained
A typical rising damp job has three parts. First the plaster on the affected walls is removed, usually to around a metre high or higher if salts have risen further. Then a new chemical DPC is injected into a mortar course along the base of the wall. Finally the wall is replastered with a salt resistant render and a finishing coat, and skirting and sockets are refitted.
The injection itself is often the smaller part of the bill. Removing and replacing plaster, making good and redecorating usually account for most of the cost, which is why two quotes for the same length of DPC can look very different. Before any DPC is quoted, anything bridging the existing DPC, such as raised soil, a high patio or render down to the ground, should be dealt with, because removing a bridge can sometimes solve the problem on its own. Read more in how to treat rising damp.
Penetrating damp repair costs explained
With penetrating damp you pay to fix the route the water is taking, not to treat the wall. A short run of repointing, a cracked section of render or a leaking downpipe is usually a modest job. A failing flat roof, parapet wall or chimney that is feeding water into the building is a much larger one, and may need scaffolding.
Once the source is fixed, the wall needs time to dry before any internal plaster is replaced. In some exposed locations a breathable masonry water repellent is added to reduce rain penetration, but it is an extra protection, not a fix for a defect.
Basement and cellar waterproofing costs
Basements and cellars are a different type of job. Below ground walls are in contact with wet soil, so the usual approach is a waterproofing system designed to BS 8102, often a cavity drain membrane with a drainage channel and sump pump, or a cementitious tanking system. Cost depends on floor area, wall height, whether the floor needs lifting, drainage and the finish required. Our basement waterproofing cost guide goes into more detail.
Condensation and mould: lower cost fixes
If the damp turns out to be condensation, the work is usually about ventilation and heating rather than walls. Typical measures include better extractor fans, positive input ventilation, opening or adding trickle vents, and treating cold spots. These jobs are normally smaller than rising damp or penetrating damp work, which is another reason to get the diagnosis right before paying for wall treatment.
The cost of leaving damp untreated
Delaying repairs rarely saves money. Damp that is left can spread salts further up the wall, rot skirting boards, joists and floor timbers, damage decorations and encourage mould. It can also affect a sale, as surveyors and buyers will usually flag it. Our guide on how much damp devalues a house explains the impact.
Can you do damp proofing yourself?
Some causes are simple to fix yourself: clearing gutters, unblocking air bricks, lowering soil against a wall or improving ventilation. DIY DPC injection kits are available, but injecting a wall that is damp for another reason will not help, and leaving salt contaminated plaster in place usually means the damp marks return. For anything beyond basic maintenance, a diagnosis first will save money.
Related guides
- How to treat rising damp
- What is a damp proof injection?
- Is rising damp covered by insurance?
- How much does damp devalue a house?
- Basement waterproofing cost UK
- Damp proofing vs waterproofing
- How much does a damp survey cost?
Get an accurate price for your property
The only reliable way to price damp proofing is to find the cause first. Our surveyors inspect inside and out, explain what they find and send a written report with photographs, so any quote is based on the work your walls actually need. Book a damp survey or read more about our damp surveys, damp proofing, rising damp treatment, penetrating damp repairs and basement waterproofing.
Frequently asked questions
How much does damp proofing cost?
A chemical DPC typically costs £70 to £120 per linear metre in London, and rising damp treatment for a two bedroom terraced house in London is often £1,500 to £2,500 including replastering. The cause of the damp makes the biggest difference.
Why do damp proofing quotes vary so much?
Usually because each company has diagnosed a different cause or is pricing a different scope. Compare the diagnosis, the walls and metres included, the plaster system, making good and the guarantee.
Is replastering included in damp proofing?
Not always. Salt contaminated plaster normally needs removing and replacing with a salt resistant render, and this is often the largest part of the cost, so check whether a quote includes it.
Is the cheapest damp proofing quote the best?
Only if it fixes the right cause and includes everything needed. A cheap DPC on a wall that is damp for another reason will not work and the damp will return.
Does damp proofing come with a guarantee?
Professional damp proofing should come with a long-term written guarantee. Ask whether it is insurance backed, so it still stands if the company stops trading.
Can I pay for damp proofing in instalments?
We offer finance options through a regulated partner, subject to status. Details are on our finance options page.
Reviewed by Michael Young, Head Contractor at Advanced Damp (CSSW and FODCS). Last reviewed November 2026.
Related Case Studies
Our recent work includes 1890s terrace, Raynes Park SW20; solid wall house, Southgate N14 and house, Surbiton KT5. Each case study sets out what the survey found and how the problem was fixed.
1890s terrace, Raynes Park SW20
Damp from a Level 3 survey traced to a blocked drain, high ground and buried air bricks.
Read the case study →
Solid wall house, Southgate N14
Moisture traced to cracked render and blocked air bricks. Fixed from outside without stripping the internal walls.
Read the case study →
House, Surbiton KT5
No active rising damp. Blocked air bricks replaced and extraction proposed to deal with condensation.
Read the case study →
Sam Fitzgerald is the founder of Advanced Damp and a working damp and structural waterproofing surveyor diagnosing and treating moisture problems in residential and commercial properties across London and the South East. He is FODCS certified (a Federation of Damp Certified Surveyor) and a member of the Federation of Damp. His hands-on work covers rising damp, penetrating damp, condensation, basement waterproofing to BS 8102, and thermal imaging surveys, and he has personally completed over 400 damp surveys across properties of every type and age. Everything he writes draws directly from jobs he has carried out. He does not write about treatments, products or causes he has not dealt with first-hand in the field.
