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

Protecting money

Fixing damp can cost from very little to thousands of pounds. Don't spend more than necessary.

Repairing your home's damp problem can be expensive - but damp problems can also be solved very cheaply. Here we look at typical costs and give you expert advice to make sure you don't end up spending more than you need to.

The reason some damp proofing can run into thousands of pounds is that the most extreme remedial works significantly affect your home's structure – that can be the only solution if you want to banish your damp for good. But some types of damp can treated very cheaply or even free of charge. 

So if you don't know what kind of damp you have, read our expert guide to identifying your damp.

Costs for dealing with damp

The cost of fixing a damp problem will depend on where in the country you live, but the table below shows the approximate costs of what you should expect to pay for some typical solutions to rising damp.

The costs of 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£15,366
Table notes: 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).

If you're a Which? member, you can log in to find recommended builders, surveyors and damp specialists in your area on Which? Local. If you're not already a member, take a £1 trial to get instant access to all the traders, as well as our in-depth product reviews - including dehumidifiers.

Don't pay for unnecessary damp treatment 

Don't assume your damp problem will always be expensive to solve. Condensation damp is reasonably easy to sort and can often be dealt with by simply opening windows more often, stopping drying clothes indoors, turning your heating on more, fitting new vents or installing new bathroom and kitchen extractor fans. And with penetrating damp, something simple such as clearing your gutters can also help.

We've heard from many Which? members who have tackled damp problems themselves, particularly condensation damp and some types of penetrating damp. 

One said: 'I cleared the blocked gutter myself. 10 minute job.' Another said:  'It was a simple issue of a tile that had come loose and I could fix that myself.'

It was a simple issue of a tile that had come loose and I could fix that myself.

 

Rising damp, which can be the most expensive type of damp to fix, is one of the least common. Our research found:

  • three in 10 Which? members have had problems with condensation damp 
  • less than two in 10 had problems with penetrating damp
  • just 8% had problems with rising damp. 

(We asked 1,592 Which? members about damp in February 2015)

So make sure you know which type of damp you have.

Get professional damp-proofing help if needed

Some problems with damp are complex and require specialist help. Don't be deterred from calling in a professional. Damp problems can worsen if left, so don't delay if you do need expert help. 

Do make sure you use a reputable firm, though. We've heard from many Which? members who advise using someone recommended by Which? Trusted Traders

I used a builder experienced in dealing with this type of problem and who could produce references

One said: 'I used a builder experienced in dealing with this type of problem and who could produce references.'

In our undercover damp-proofing investigation (scroll down for more information), we found that households could be spending hundreds of pounds on unnecessary damp-proofing treatment.

So to make sure you're not overcharged, you should get quotes from at least three companies and seek advice from an independent damp specialist if there are inconsistencies in the work recommended. This way, you'll find out whether or not the treatment is absolutely necessary, and will be able to weed out any firms that try and make you pay over the odds.

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.

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

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

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