How Much Does It Cost to Damp Proof a House?

Damp proofing being installed on a house

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October 30, 2023

It always makes sense to damp proof a house: not to do so is foolish. Dampness in a building rots the structure and adversely affects the effects of those living or working in it. Why wouldn’t you? Well, one thing that may make homeowners think twice is, of course, the cost.

So, if you’re currently wondering how much it costs to damp proof a house,’ read on. We have all you need to know right here in this article. It tells you about the different types of damp, how much a damp proof specialist costs and what you can expect to pay for treatment.

Average Hourly and Day Rates for Damp Proofers

The average hour or day rate you will pay for a damp proofer depends on where you live in the UK, how experienced the individual or established the company is, and what you’re having done.

Day Rates

You can expect to pay anything from £100 up to £200 a day when you get a professional damp proofer. The number of days you will need them for depends on the type of damp you have and how big the patch requiring treatment is.

Hourly Rates

Due to the fact installing a damp proof course in a house often takes days, the majority of damp proofing specialists charge per day or per course. Rarely will you find damp experts charging an hourly rate.

Costs by Type of Damp Proofing

Damp proofing your entire home can cost from as little as £300 up to £2500. It just depends on how big your home is, what form of treatment the damp proofing takes and where you live in the UK. There’s also the matter of which of the different types of damp the problem falls under.

Damp Proof Course

Expect to pay around £70 per meter of wall for damp proofing. For a typical wall that works out at around £280. At that rate, costs for a whole house will run into thousands of pounds. You will also need to coat the internal walls in damp-proof paint. For this, you’re looking at anything from £20 up to £50 per litre of paint. Applying damp proof paint can take from six to 12 hours per room.

Tanking Slurry

If the damp proofing you’re having involves a tanking slurry then this will take quite a bit of time and effort on behalf of your damp specialists. That’s because they will have to remove the plaster, paint and any debris from the surface of the wall in order to retank it. This involves first wetting the wall a little, filling up any holes in it with cement, mortar and a waterproofing material and then finally applying a tanking slurry.

The wall is left to dry for a period of 24 hours, after which yet another coat of tanking slurry is applied. Once this in turn has dried, the wall is replastered.

Costs for a tanking slurry – which is usually applied in basements – range from £30-£60 per square metre of wall.

Re-plastering

Replastering your walls after a damp proof course means applying an initial layer of PVA to ensure that, when it’s dry, the plaster sits evenly.

The first coat of plaster sits for around 20 minutes before being skimmed and then a second thinner coat of plaster is applied. Water can smooth out any bumps while sanding is used to smoothen the wall and remove any surplus plaster.

A bathroom

Damp Proofing Costs in London

Whether you’re treating exterior walls or the interior of your home, if you live in London then you can expect to pay more for a damp proofing specialist. This is due to the higher cost of living and can result in average costs of up to £70 more per day.

Additional Costs

When having your home damp proofed it’s not just the labour and materials you’ll pay for. Often there are other costs too that can add to the bill. These are mainly to improve the longevity of the damp proofing, or to assist in its installation. They include the following:

  • Purchasing a dehumidifier – up to £100
  • Purchasing an extractor fan – up to £250
  • Resealing a window – around £60
  • Purchasing a new window – up to £350
  • Resealing a door – around £100
  • Purchasing a new door – up to £1500
  • Replacing gutters – up to £700
  • Repairing a leaking roof – up to £100 per m2

Factors That Affect Costs

The state of the dampness in your home will certainly affect the cost of damp proofing. If it’s a few patches caused by condensation, then that’s going to cost a lot less than an entire wall with rising damp.

The type of treatment you receive will also have a bearing on cost. So too will any plastering and decorating work you have carried out once the wall, ceiling or flooring has been treated. You may also want to purchase a dehumidifier or an extractor fan to ensure the problem remains at bay in the future.

Costs for Different Damp Proofing Jobs

Damp proofing costs, on average, around £60 per metre. Here are further estimated prices for damp proofing particular areas in the home:

Damp proofing external walls

To make external walls damp proof they must have no holes or cracks into which water can seep. To ensure this an external damp proofing course costs around £1,500 on average.

Damp proofing a chimney

The entire chimney breast and stack is usually involved when damp proofing a chimney. The dampness can be caused by any number of problems, such as rising damp, a blockage in the chimney, a missing chimney pot or a gap in the exterior wall mortar. Once the cause has been fixed a damp proof course can be applied. Average costs are around £75 per roll of damp proofing membrane. There’ll also be scaffolding and labour costs on top of that.

Damp proofing a cellar or basement

It’s common for basements to suffer from damp and, because we don’t tend to use this room as often as others in our home, the problem can grow quite substantially until it’s noticed. The cost for this is around £45 per sqm.

Injection damp proofing

Injecting a damp proof solution between the ground and the foundations of your home typically costs around £3,500.

Chemical damp proofing

It’s also possible to use chemicals to build up a barrier between the ground or external environment and your home. This comes at average costs of around £1,900.

Reasons to Damp Proof Your Home

A problem with dampness in your home is something that has to be tackled immediately. Or at least, as soon as you can get in a specialist. There are plenty of reasons to deal with dampness but know that the longer it’s left, the worse it will get and the more expensive it will be to treat. That’s because it can adversely affect the structure of your building.

And then there’s the smell of dampness. It results in a foul smell to the extent that allowing dampness to expand also means more mould on your walls. This, of course, can lead to health problems, particularly for those living in the house who suffer from asthma, reduced lung function or any other respiratory problems. Damp will make this condition much worse. For others it can also result in chest problems, congestion, headaches and throat irritation.

Not only is damp unpleasant to smell, it’s not exactly glamorous to look at either. It causes large unsightly damp patches on interior walls with the moisture causing wallpaper to fall off and paint to crack.

Try and sell your home while there is a damp problem either at ground level or on the walls, then you will no doubt get short shrift from potential buyers. Either that or they will insist on a substantial reduction in the selling price so that they can pay for a cost of damp proofing themselves.

Types of Damp

There are three ways that damp can become a major problem for homeowners. The first is condensation, the second rising damp and the third – and worst – condition is penetrating damp. Each different type of damp has to be dealt with separately and, as such, costs vary substantially.

Damp from Condensation

Condensation is the most common type of damp in the UK today. It’s when warm water vapour builds up in a room, causing moisture, which then clings to the side of a shower, cold walls, the ceiling and even the floor. Left to sit there, it turns into mould.

Because you cook, boil a kettle or bathe in them, both the bathroom and the kitchen are the rooms in the home most likely to have a problem with dampness. It’s also more common in winter than in summer because the walls are so much colder then.

Other factors which result in condensation are central heating (it cools rapidly, resulting in warm damp air) and poor ventilation in the home).

If condensation builds up on windows then it can eventually decay window frames. The same for door frames and for walls where it will affect the plaster.

A radiator that has been removed from the wall

Rising Damp

As its name suggests, rising damp is when dampness grows upwards, usually from ground level, with water sitting in the foundations of your home. The dampness spreads to the floorboards and walls.

This type of damp is more prevalent in older, traditional homes, such as Victorian tenements and Georgian semis etc. That’s because these weren’t built with damp proofing in mind. It’s also common in homes where there isn’t a lot of drainage around.

You can tell you have rising damp if you spot tide marks on the wall. Another giveaway is your walls develop wet patches and the wallpaper or paint starting to peel. Plaster and skirting board damage is another indicator of a problem with rising damp. A lesser-known pointer of rising damp can be finding a white, powder-like substance on the walls due to salt in the water.

The solution to rising damp usually involves applying a damp proof course to prevent the moisture from rising. To do this, holes are often drilled near the base of the damp walls where they are injected with a chemical substance.

The cost of rising damp treatment is usually in the thousands of pounds range, often reaching £5,000 if severe.

Penetrating Damp

This type of damp is caused by moisture seeping through the external walls of your home. It enters through holes in the wall or roof and converts to dampness, mould and, if left long enough, structural damage. Ironically though, it’s usually caused by structural damage in the first place, such as missing roof tiles or cracks in the wall.

Having said that, penetrating damp can also be caused by a leaking pipe inside the home.

Once again, older homes tend to be more prone to penetrating damp than new builds. That’s because not only do many older homes not contain a damp proof membrane, but they don’t have cavities in the walls either.

Again, damp patches are an indicator of penetrating damp – especially patches which appear darker when it’s raining outside.

The good news is that this type of damp problem is relatively easy to sort. It’s not as expensive as rising damp treatment, for instance. Depending on how bad the damp patches are you’ll pay anything from £400 to £4000 for a severe problem.

DIY Vs Hiring a Professional

If you are planning to damp proof your home DIY-style then you’ll need to buy damp proof injecting cream. This costs up to £7 per 100ml. Anti-damp proofing paint at around £25 per tub is another necessity.

You’ll also need to be pretty sure about what you’re doing. It’s easy enough to get rid of a small condensation difficulty – ventilate or bring in a humidifier. But, if the dampness is a real problem then it can take time and a fair amount of expertise to get to the bottom of it all. Fail to do this and you’ll just build up future problems, and spend more money fixing it.

And that’s why it’s often best to get in a professional from the start. They will be able to inspect any damp patches on the walls, check if your existing damp proofing course is up to scratch and, if not, inject the walls with chemicals to help them withstand moisture. They’ll also be able to plaster and skim the walls for you.

Finding a Damp Proofer

When looking for an expert damp proofer to fix difficulties with damp you and your family are experiencing, there are quite a few methods you can employ. In addition to looking at damp proofing associations for someone registered who lives near you, try the following:

The Page

When you send us an enquiry here at The Page, we will match you up with a curated list of expert tradesmen. All of them will be specifically suited to work on your project.

Let The Page curate you a free bespoke shortlist of tradespeople suited to you and your job.

We take the time to personally meet each and every one of our tradesmen. This gives us the opportunity to carry out checks on their work and identity. It also allows us to look at their previous work and to ask any questions there and then. That way you can be sure that when you hire from The Page, you hire an expert tradesperson, whatever the job.

Online Search

Look online and you will find damp specialists offering to solve your rising damp, condensation or penetrating damp problems. Some of them may even be local to you. The only problem with hiring someone from a directory or a google search is that if there are reviews you can’t be sure that they are genuine. And, if they don’t have a website, you won’t be able to check past work examples or testimonials either. Neither can you guarantee their expertise in the subject.

Ask Around

There is certainly nothing wrong with a recommendation for a damp proofing expert from a family friend, distant cousin, work colleague or neighbour. This way you will be able to ask questions about the individual or company’s working methods and how long they took.

Preventing Damp

To prevent damp becoming a problem always call in a specialist. But don’t wait too long. That’s because they may be busy. Why? Because dampness is actually one of the biggest worries for homeowners here in the UK. Then again, that’s hardly surprising really when you consider just how many days of rain we get year-round.

Any type of property can suffer from the scourge of dampness. In other words, the problem doesn’t discriminate. It can affect newer detached houses, studio apartments, terraced houses and even luxury mansions. And it can cause structural damage to each and every one.

So, to prevent damp, have your property checked on a regular basis for any cracks to the walls, fallen masonry, broken gutters and wet flooring. That way, if a problem does develop you will be able to tackle it at source and before it becomes an even bigger, and more expensive, problem.

Even if you’ve recently moved into your home and been assured a damp proofing course was installed previously, it’s still worth checking since over time it may have stopped working.

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