How Much Is Damp-Proofing Per Square Metre? Prices by Method and Property Type

Author : RBG ROOFING LTD | Published On : 05 Oct 2026

Quick answer: Damp proofing in the UK typically costs £25 to £120 per square metre, depending on the method. A chemical damp-proof course (DPC) is usually priced per linear metre, at roughly £40 to £100. Whole-house treatment commonly lands between £1,000 and £5,000. These are indicative 2026 figures, and the real number depends on the cause of the damp, the wall type and your region.

If you've searched how much is damp proofing, you've probably seen quotes that look nothing alike. One contractor charges per metre, another gives a flat fee, and a third wants to replaster the whole room. This guide breaks down what damp proofing costs per square metre, why prices vary, and how to avoid paying for a fix your home doesn't need.

So, How Much Is Damp Proofing Per Square Metre?

Damp proofing has no single price. Cost depends on the method, and the method depends on the type of damp. Here is a realistic guide to UK costs.

Treat these as ballpark ranges, not fixed quotes. Prices in London and the South East tend to run higher than in the North or Midlands, and access, wall thickness and the condition of existing plaster all push the figure up or down.

Why Damp Proofing Prices Vary So Much

Three factors drive most of the difference between quotes.

1. The type of damp. Rising damp, penetrating damp and condensation are three different problems with three different fixes. Treating condensation with an injected DPC wastes money, and ignoring a leaking gutter while you replaster guarantees the damp returns.

2. The size and construction of the property. A solid-wall Victorian terrace needs different work from a 1970s cavity-wall semi. Thick stone or brick walls take longer to treat and need more product.

3. The scale of the repair. A single damp patch behind a sofa costs far less than treating every ground-floor wall, and the cost of making good afterwards (plastering, skirting boards, redecorating) adds up quickly.

Damp Proofing Costs by Method

Injected damp-proof course (DPC)

A chemical DPC is the standard treatment for rising damp. Small holes are drilled along the base of the wall and a silicone-based cream or gel is injected, forming a water-resistant barrier that stops moisture travelling upward through the masonry.

It is normally priced per linear metre of wall. Expect roughly £40 to £100 per metre, and £500 to £1,500 for a typical single-wall treatment. If you want to see how these figures play out on a real job, this guide to what a damp course costs walks through the main pricing factors. Most reputable installers back the work with an insurance-backed guarantee, often 20 years or more.

Cementitious tanking

Tanking applies a waterproof cement-based slurry to the inside of a wall, most often in cellars, basements and below-ground rooms. Costs usually fall between £30 and £80 per m². It is effective but unforgiving: poor surface preparation is the main reason tanking fails.

Cavity drain membranes

A cavity drain membrane system, sometimes called a studded membrane, doesn't stop water entering. It manages it by channelling water to a sump and pump. It is considered one of the most reliable options for basements and conversions, at roughly £40 to £120 per m² depending on drainage requirements.

Replastering after treatment

Salt-contaminated plaster usually has to be removed and replaced with a specialist salt-resistant render or plaster after DPC work. Budget £25 to £60 per m² on top of the treatment itself. This is the cost people most often forget.

Ventilation and condensation control

If the real culprit is condensation, you don't need injections or tanking. Better extraction, trickle vents, a dehumidifier or a PIV unit may solve it for a fraction of the price. For many homes, this is the cheapest fix of all.

Damp Proofing Costs by Property Type

Older homes often cost more because breathable lime plaster and traditional materials may be needed, and the wrong product can trap moisture inside the wall. Listed properties may also need consent for certain works.

Rising Damp, Penetrating Damp or Condensation?

Before asking how much is damp proofing, it helps to know which problem you actually have.

• Rising damp appears as a tide mark, usually no higher than about a metre above the floor, often with peeling paint, crumbling plaster and white salt deposits.

• Penetrating damp shows up as isolated patches that get worse after rain, caused by defects in the building envelope such as cracked render, failed pointing or a leaking roof.

• Condensation typically appears as black mould on cold surfaces, streaming windows and a musty smell, particularly in poorly ventilated rooms.

The first two are the ones most often confused, and the difference changes the price dramatically. This guide on how to spot rising damp vs penetrating damp covers the telltale signs in more detail.  

This is where the roof matters more than most homeowners expect. Blocked gutters, slipped tiles, failed flashing and damaged chimney stacks are leading causes of penetrating damp, and they are often misdiagnosed as rising damp. A roofer who understands the whole building envelope can spot these faults early. At RBG oofing Ltd, fixing the source of water ingress is usually the first step, because no chemical treatment will cure a leak that is still feeding the wall.

What Affects the Final Price?

• Severity and extent of the damp

• Wall thickness and material (brick, stone, cob, concrete)

• Access, including furniture, fitted kitchens and scaffolding for external work

• Plaster and finishes that need removing and replacing

• Location, since London and the South East are generally more expensive

• Guarantees and certification, as insured, accredited installers cost more but protect you

• Survey fees, which vary by provider

How to Avoid Overpaying for Damp Proofing

1. Get a diagnosis first. An independent survey from a qualified surveyor, such as a CSSW (Certificated Surveyor in Structural Waterproofing) or a surveyor with PCA (Property Care Association) credentials, has no incentive to oversell.

2. Get at least three written quotes that show the method, area, materials and guarantee.

3. Check the cause has been fixed. Gutters, downpipes, roof coverings, ground levels and pointing should be checked before any internal treatment.

4. Ask about guarantees. Insurance-backed warranties matter if the contractor ceases trading.

5. Look for accreditation. PCA membership and compliance with relevant British Standards, including BS 5250 (managing moisture in buildings), are good signs.

Is Damp Proofing Worth the Money?

In most cases, yes, provided the diagnosis is right. Untreated damp can damage plaster, timber joists and skirting boards, encourage mould growth and reduce a property's value at sale. Lenders and buyers' surveyors regularly flag damp, and a documented, guaranteed treatment can reassure both.

The real risk is not paying for damp proofing. It's paying for the wrong damp proofing.

Conclusion

So, how much is damp proofing? For most UK homeowners, expect £25 to £120 per square metre depending on the method, or £1,000 to £5,000 for a full property. The number matters less than the diagnosis. Find the true source of moisture, fix the building envelope first, then choose the least invasive treatment that solves the problem.

If you suspect water is getting in through your roof, gutters or chimney, contact expert roofing contractors they can inspect the building envelope and give you a clear, honest assessment before you spend a penny on internal damp treatment. 

Frequently Asked Questions

How much is damp proofing for a whole house in the UK?
Most UK homes cost between £1,000 and £5,000 to treat, depending on size, damp type and finishing work. Large or period properties can cost more.

How much is damp proofing per metre?
Injected DPC typically costs £40 to £100 per linear metre. Tanking and membrane systems are priced per square metre instead.

How long does damp proofing take?
Chemical DPC installation often takes one to three days. Replastering and drying-out add time, and walls can take several weeks to dry fully.

Does home insurance cover damp proofing?
Usually not. Standard policies tend to exclude gradual damp, though sudden damage such as a burst pipe may be covered. Check your policy wording.

Can I damp proof a wall myself?
DIY injection creams exist, but results are inconsistent and rarely come with a guarantee. Professional work is generally recommended for anything beyond minor repairs.

How do I know if I need damp proofing or a roof repair?
If patches appear on upper floors, near chimney breasts or after heavy rain, the cause is often roof-related rather than rising damp. A roof and gutter inspection is a sensible first step