Dealing with damp How much does it cost to repair damp?

Prices for dealing with damp

The cost of fixing a damp problem will depend on the extent of the problem and where in the country you live. The table below gives approximate costs of what you can expect to pay for some typical  solutions.

Prices for dealing with damp
ProblemSolutionTerraced house - one wallTerraced house - whole houseSemi-detached house - one wallSemi-detached house - whole houseDetached house - one wallDetached house - whole house
Ground level is above the existing damp proof courseExcavate soil only£204£268£262£594£437£1,456
Ground level is above the existing damp proof courseExcavate soil and lay pre-cast concrete paving slabs£431£728£600£1,491£1,036£3,274
No damp proof course in wallInject silicone damp-proofing course£221£350£384£769£600£1,899
Internal walls are dampAsphalt tanking to 1.2m height and decorate to full height£1,631£3,250£2,435£6,477£4,858£15,3666

These costs are from the Building Cost Information Service, which is part of the Royal Institute of Chartered Surveyors. The costs include everything necessary to carry out the work including labour, material and VAT (correct as of December 2011). 

Which? members can find recommended builders, surveyors and damp-treatment companies on Which? Local. If you're not already a member, sign up for a £1 trial to get instant access to all of, Which? Local and receive Which? magazine.

Don't pay for unnecessary treatment 

In our undercover damp-proofing investigation (published in Which? in January 2012) we found that households could be spending hundreds of pounds on unnecessary damp-proofing treatment.

If you are considering damp-proofing treatment, you should make sure it is absolutely necessary by getting quotes from at least three companies and seeking advice from an independent damp specialist if there are inconsistencies in the work recommended. 

Damp-proofing investigation

In a snapshot assessment, Which? invited 11 damp-proofing companies to two houses with a total of three potential damp problems. These visits were then analysed by three damp-proofing experts, who found that in two thirds of cases the companies recommended unnecessary or inappropriate treatment, or missed the problem completely.

Five of the 11 damp companies that visited the first property recommended completely unnecessary treatment according to the experts – some costing as much as £1,440 – when they essentially should have suggested getting a plumber to fix a leak.

In the second property, only two of the 11 companies recommended a suitable solution for the penetrating damp problem in the hallway. Also in this property five companies failed to notice the likely damp penetration/rising damp problem at the front of the house. Of those that did identify it, only four recommended a suitable treatment.

Our full investigation findings appeared in Which? magazine. To try Which? magazine and get full access to our website sign up for a £1 trial.

Damp-proofing company scores 

The overall scores for the biggest companies (how many occasions they gave good advice) were as follows:

  • Peter Cox 2/3
  • Rentokil 2/3
  • Kenwood 1/3
  • Lifecote 1/3
  • ProTen 1/3
  • Timberwise 0/3

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