Average Cost to Damp Proof a Wall (DPC)

Have you discovered damp in your property and are now looking for a damp proofing price? Not only can we provide you with a guideline cost for this work, we can explain the process involved. We believe our research is very insightful and you might be surprised to know that damp proofing walls isn’t always the answer to these problems.

About Us and Our Damp Proofing Price Guide

Quotation Check was launched in 2014 and is now one of the most popular home improvement cost comparison websites in the UK.

We gather quotations and estimates from businesses, companies and individual traders before posting an average price on our pages.

We also ask our contractors probing questions and provide you with hints, tips and advice, so you can get the right job completed at a fair price.

The prices you see further down this page were sourced from damp proofers during January and February 2017 and we last updated this page on the .

Don’t forget; this is just one of hundreds of insightful price guides we have created. See our full price list here.

damp on wall

A Word of Warning (read this first)

The prices you see on this page are for a property in Surrey that requires a new injected external DPC and some minor repairs to internal walls.

You should not confuse this scenario with a house that has severe damp problems across multiple walls. That will cost more, ripping out plaster to multiple walls, waterproofing, sealing, replastering and decorating is very disruptive and in some cases can cost tens of thousands of pounds.

If your property suffers from anything more than isolated patches of internal damp, then disregard our prices below and get a customised quote based on an inspection of the property.

What You Get For Your Money

Here is a brief summary of the work that is involved with damp proofing a wall:

  • Full inspection of walls with damp meter.
  • Visual inspection of walls and any existing damp course.
  • Removal of skirting boards and areas of damaged plaster to internal walls.
  • Injection of waterproof liquid into walls.
  • Waterproof sealer applied to sections of internal wall and then finished off with plaster.

How is the Waterproof DPC Inserted Into the Wall?

Because the wall is already built it would be extremely difficult and costly to try and insert a plastic sheet between the bricks. A more common method is to drill 12mm holes every 100mm along the chosen course and then inject a chemical waterproofer into the wall. The porous bricks and cement will soak up this liquid and when it sets it will provide a waterproof layer, any moisture below this new DPC cannot rise above that course.

The internal side of the wall will also have to be treated, this will involve removing some plaster and replastering afterwards.

How much plaster needs to be removed will ultimately determine how much this work costs. There is a big difference between removing small areas of plaster and removing all of it.

There are several different ways to insert the chemical into the wall. Some companies use a high pressure system, others use a drip-feed system that allows the bricks to soak up the liquid over a 48 hour period. Newer systems involve creams that are squeezed into the pre-drilled 12mm holes.

Common Causes of Damp Walls

In many cases a damp course need not be replaced, it could be that the existing damp course is sufficient but has been bridged.

This is when moisture is allowed to come into contact with the bricks above the damp course. The most common causes of this are:

  1. Raising flower beds so moist soil is above the damp proof course.
  2. Laying a patio or concrete floor above the damp proof course.
  3. Discharging rainwater from gutters near the wall so it frequently splashes the brickwork above the DPC.
  4. Having the external wall poorly rendered so the cement “bridges” the DPC.

In all of the four examples above, the solution isn’t to install a new DPC but to take other actions; dig out the raised flower beds, lower the patio or put in a drainage channel next to the wall so water is channelled away from the wall. Make sure rainwater discharged from guttering cannot splash onto the wall above the DPC. Remove any external render that has bridged the DPC.

Cost to Damp Proof a Wall

Below are three examples of what you can expect to pay for common damp proofing work. The prices are based on our research. They do not include VAT as some of the smaller contractors we contacted were trading below the VAT threshold.

1) Inject Liquid Waterproof Sealer Into Damp Course

This price is for a 2-bed semi detached property located in Surrey. The work involves injecting a damp proofing liquid into the external walls. No internal work is required.

LocationSmall BusinessLarger Business (5+ employees)
Need a Custom Price? >Compare Up To 3 Personlised Quotes Here
Surrey Area£1100.00£2000.00

2) DPC to External Walls and Repair to Internal Walls

This work will involve a new DPC inserted into the walls of a 2-bed house, removing patches of damp plaster from internal walls, also some sealing and plastering work to the internal walls. This work is for relatively minor damp located in several areas near the bottom of the wall (the most common).

The prices below are not for a property that has severe damp issues across all the walls. That would involve a complete strip out of the plaster (possibly floor to ceiling) and the cost to seal and plaster afterwards will be considerably more than our figures. For the most severe cases of wall damp, you could easily double our prices below, perhaps even more.

LocationSmall BusinessLarger Business (5+ employees)
Need a Custom Price? >Compare Up To 3 Personlised Quotes Here
Surrey Area£3250.00£4750.00

3) Inserting Drainage Channel

This quote is to insert a channel around one side of the building on a semi-detached house so rainwater is channelled away from the walls and cannot come into contact with the bricks. We assume that there is a patio, tarmac or concrete that has been laid too high and has compromised the existing DPC. The channel will be filled with large stones and connected into an existing soakaway which is located close to a rainwater downpipe.

This type of work can be done by a general builder, a landscape gardening firm (hard landscaping) or by a patio specialist.

We asked some friends and family members to source quotes for us, so you see what this work costs at various locations around the UK.

LocationSmall BusinessLarger Business (5+ employees)
Need a Custom Price? >Compare Up To 3 Personlised Quotes Here
London Area£850.00£1200.00
South, SW and Midlands£700.00N/A
Outer Region and North£550.00N/A

The Next Step? Arrange a Custom Quote Today

Our research is very insightful and we often receive letters and messages of thanks from our visitors. If however, you want a truly accurate price, you will need to arrange a custom quote.

For damp issues, we cannot emphasise enough how important it is to get a personalised quote rather than relying on our figures. The issues with your property may be far more serious than the ones on our test house.

  • Provide specifics of your damp problem
  • Get up to three quotes in return
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  • No obligation or commitment whatsoever
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Don’t Get Conned – Get Independent Advice

The best advice we can give you is to have your damp walls inspected by an independent surveyor. It will cost more initially but they can give you independent advice, if you don’t need a new expensive DPC then they will advise you of that.

If you get a damp proofing specialist to inspect your walls, chances are they will try to sell you a damp proof course. That is after all what they do and this type of work is very profitable.

The damp proofing industry has a bad reputation in the United Kingdom. There is widespread mis-selling of unnecessary wall treatments when the main cause of the damp is the existing DPC being bridged.

Why is Damp Proofing so Costly?

The wall injection itself isn’t time-consuming or costly, but the plastering and making good of the walls certainly is. It’s also a very messy job and you will probably want to move out of the house for a few days first.

Don’t Leave it Too Late

Whatever the cause of your damp walls, it’s always best to act quickly and tackle the issue as soon as possible. Damp can spread quickly, especially through porous bricks and plaster which can then disintegrate. It can rot timber floor joists, skirting boards and other woodwork.

There is also a health hazard – living in a property that is damp for long periods of time is bad for the respiratory system.

The DIY Option

It is certainly possible for anyone with basic DIY skills to insert a waterproof DPC into an external wall. 12mm holes are drilled 3/4 of the way through the brick course above the existing DPC at 100mm intervals. A cream is then squeezed into the holes via a mastic application gun. A small dollop of cement is then used to plug the gap.

The difficult part is the internal walls. The plaster really does need to be removed to gain access to the bricks behind.

If finances are a real issue, a homeowner could try and seal only the outer wall, then wait and see the results. If the internal plaster isn’t too badly damaged then it may dry out.

The video below explains how a damp proof course is inserted into a wall:

Avoid Doing This:

If you are on a tight budget you might be tempted to paint the interior walls with a waterproof paint/sealant to mask any signs of damp.

This work should never be carried out – if there is still a damp issue then it will eat away at the cement, bricks and plaster behind the wall. This can lead to serious issues which will lead to further expense in the future.

A wall should only be painted with a waterproof if you are 100% certain that there is no damp rising from the ground below, otherwise you are just masking the issue.

Feedback For Our Guide to Damp Proof Costs

Have you received quotes from tradespeople and companies for wall damp proofing? What costs are they charging for this type of work?

Did you find our article helpful? Please leave a comment below at the base of the page and share your thoughts with other readers!

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6 Responses to “Average Cost to Damp Proof a Wall (DPC)”

  1. Christina WilliamsOctober 19, 2015 at 6:45 pm #

    This was very helpful, I think i might attempt to do this myself.

  2. Jennifer StoneDecember 12, 2016 at 12:14 pm #

    I found this very useful. I am looking to buy a bungalow which needs some work and this site was very useful as it gave me a rough guide to costs but also things for me to check ie patio laid to high.

  3. MurtazaDecember 19, 2016 at 12:27 pm #

    Thank you for explaining the issue in detail.
    Extremely useful guide.

  4. C StainsbyAugust 6, 2017 at 5:29 pm #

    Buying a Victorian house with dampness. Found this guide very informative and good to give a guidline on the pricing required. Thank you again.

  5. James BusbyAugust 9, 2017 at 8:55 am #

    As a qualified conservation builder, PgDip(MA) Conservation of the Historic Environment, your advice on damp is misleading.
    For cavity walled properties (approx 1920 onwards) any breach of the cavity internally will cause damp. This has been shown recently through the use of cavity wall insulation. The cavity is there for a reason leave it alone.
    For older historic and heritage solid wall buildings you must apply the concept of “breathability” of walls and the use of historic building materials e.g. lime mortar and plaster. Remember there is no such thing as rising damp. Problems occur when the walls are injected, coated, rendered or plastered in hard gypsum, cement, or plastic based products or paints.
    Under no circumstances should you allow so called specialists damp proofing companies to beguile you that you need chemical processes to cure the problem.
    Sadly the banking system in this country has been convinced by this industry that they are the answer to all damp issues. If you try to borrow money to buy an old property you are perpetuating the destruction of this country’s housing stock.
    The Council of Mortgage Lenders will require this totally unnecessary work to be done because your mortgage surveyor is too cowardly to advise on the problem and may not even know how to deal with it. They in turn will pass it on to the Property Care Association who are the governing body charged with giving you a “free” quote from one of their “trained” (3 day course in how to use a drill and mastic gun) operators. It is likely, based on their quote that mortgage monies will be retained and your mortgage provider will insist on the work being carried out.
    Bear in mind that your mortgage lender knows nothing about maintaining old property. They are led by the PCA. Until those responsible for lending understand the concept of Heritage property maintenance and repair they will carry on destroying our building history.
    Your the customer and you should tell them they are wrong. By using the PCA they are damaging the very asset they are lending money on.
    For further information about go to

  6. Mrs harrisDecember 9, 2017 at 6:10 pm #

    My lender has insisted on a damp and timber survey to my 2bed stone cottage as there is condensation in the corner bedroom wall and lounge wall below. His cost in north Wales is £4320 inc vat!

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