Cost of Rising Damp Treatment

Want to know how much damp proofing costs?

Here we breakdown different rising damp scenarios and the costs associated with treating them.

You must treat rising dampness sooner rather than later. The implications of not doing so could not only be damage to your property but also your health.

How much will rising damp cost to treat on average?

The cost of fixing rising damp and applying dampness treatment can be anywhere from £200 to £5000 depending on the scale of the problem.

Our guide covers everything you might need to know about rising damp, including detailed cost overviews and what's involved with the treatment.

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How Much Does Damp Proofing Cost?

The cost of repairing rising damp can vary wildly. The main factors affecting how much you will pay include the type of home you live in, the severity of the damaged caused by the damp, and the cause of the rising damp.

Treating rising damp in a terraced home will cost less than a detached home. This is because there are fewer external walls to be dealt with. The more walls you have, the more it will cost to fix.

The damage caused by rising damp can be extensive. For you to know that you have rising damp, you will have seen some damage, for example, stained walls. The plaster on these walls will need to be taken off and replaced.

When you investigate the rising damp, you might find damage that you couldn't see, for example, rotting floor joists. The longer you put off treating the issues, the more it is likely to cost.

There are several causes of rising damp. They all boil down to issues with the damp proof course (DPC) in your home. If the DPC is just bridged by another material, this can be an easy fix. If you need to replace the DPC for your whole home, then it gets more expensive.

For the easiest possible situation with minimal damage, it could cost as little as £400 to fix all the problems and the damage. If the issue has been left unchecked and causes extensive damage, you could be looking at as much as £16,000.

Rising Damp Treatment Prices

The cost of treating rising damp depends on what type of damp treatment you decide to use, or what’s best for your situation. Below you’ll find some damp treatment costs:

Damp Proof Course Prices

The price of installing a new DPC depend on the type of DPC that you choose and what sort of home you have. The below table gives you some average costs:

Drainage Channel Costs

Getting a drainage channel installed is a common option for recurring rising damp issues.

This rising damp treatment cost can vary significantly based on the finish you want and the type of home you live in. The table below gives the average costs for a range of options:

Cost Of Clearing Out Cavity Walls

This includes the cost to replace the removed bricks. The average cost assumes all the work needing to be done is within 3m of the ground.

Additional Costs

New Skirting Boards

For any effective treatment, you will probably need to remove your existing skirting board. Some of it might be salvageable, but if the damp has gotten into it, then it may be rotten.

If this is the case, you will need to replace the skirting board. Skirting board is priced at around £2 per metre. If you have to replace all of the skirting board in an average-sized room, then it will cost around £250 for both labour and supplies.

This could be an ideal opportunity to upgrade to heated skirting boards which would aid in preventing your damp issue from returning.

Painting and Decorating

When you are all done fixing the cause of the damp, you will likely be left with a room that is newly plastered.

This means you will need to redecorate. If you get a decorator in, you are looking at average prices of £300 for painting and £400 for wallpapering a room.

You can save quite a lot of money by choosing to decorate yourself.

Replacing Flooring

If you’ve had to take up the floor to deal with the damp issues, then you will need to pay to replace it. The price of this will depend on the type of flooring you choose.

For wooden flooring, you are looking at around £215 for an average-sized room. For carpet, you can expect to pay around £150 depending on the carpet and underlay you choose.

Replacement Floor Joists

If the damp has caused your floor joists to rot, then you will need to replace them. They can't be fixed. The cost will depend on how many joists need replacing. You can expect costs of around £250 per joist.

Plastering

If the treatment you choose requires the plaster to be removed from your walls, then you should check that the price you have been quoted includes plastering.

This will normally involve just re-plastering the bottom of the wall and blending it in with the old plaster. If your walls are not in great condition, you might want to consider getting them all re-plastered whilst you are having work done.

The cost to plaster an average-sized room is about £650. To just get the walls reskimmed, would be £480.

Rendering

If the damp has damaged the masonry of your home, then you might need to consider getting it rendered. You can just get small areas patched, or you can get the whole house done so that you get an even finish.

The cost of patch jobs will depend on the contractor you choose. To get a whole two-story house done you are looking at about £4,800 for a semi-detached property and £7,300 for a detached one.

Moving and Storing Furniture

Depending on the scope of the work you will be having done, it might be necessary to remove and store some of your furniture. To have the furniture removed and stored you are looking at costs of around £75-£100 per month.

Waste Disposal

If there is a lot of plaster or rotted timber to remove, then you will likely have to pay for waste removal. Depending on the size of the job, this may involve the hire of a skip. The average price for this would be around £250.

Supply Only Costs

There are a few treatment options that you could carry out on your own. Most options should be done by a trained professional. Here is the DIY cost of fixing rising damp in the table below:

Labour Costs and Timescales

The largest cost involved in treating rising damp will be the labour costs. It is always worth checking your chosen contractors 'per day rate'; this is because there are often surprising extras that can take up time and will push your final cost up.

These average costs include the labour to remove old plaster and replace it where necessary. The duration assumes that two people are working on the job the whole time.

Cost Factors of Treating Rising Damp

There are a lot of factors that affect the cost of getting rising damp treated. This is why the costs can vary so much. A lot depends on your individual circumstances.

Severity of Damp

The longer the damp has been left untreated, the more damage it will have caused. If previous occupiers have ignored or covered up signs of damp, then you might find that a lot of damage is hidden under the surface. Once you start investigating, you might find a lot of problems.

If there has been rising damp in multiple locations for a long time, the damage can be extensive and can begin to affect the structure of your home. If the damp is limited to a small area and is found quickly, the effects can be reversed by just drying out the affected area.

Type of Treatment

The type of treatment that you eventually go for is going to depend on the cause of your rising damp. Some issues are easy to fix; they might just involve moving some earth or taking off some plaster or render.

Other treatments might require you to remove a lot of internal plaster and inject a new DPC. The more labour and time-intensive treatments cost significantly more.

Size of Area That Needs Treating

Depending on what has caused the rising damp, it might be limited to a small area. For example, if an increased soil level is the cause, it might just be against one section of a wall.

This means the damage is not widespread, and it will be cheap to fix. In the case of a missing or damaged DPC, you are looking at issues along each external wall, which will multiply how much the whole job costs.

Replacing Rotting Timber

If the damp has gotten into the timbers of your home, then you will have to pay for the materials to replace the rotten wood. As well as the skills of a carpenter. These costs can rapidly rise. The more wood that has been affected, the more the damp proofing price will rise.

What's Involved in Treating Rising Damp?

Installing a Physical DPC

If you have an existing DPC, then this will be removed in sections, and the new plastic DPC inserted. If you don’t have a DPC, then bricks will be removed at the level the DPC needs to be added. They will then be re-laid with the DPC layer inserted between them.

Installing a Chemical DPC

The chemical DPC will be injected into both your interior and exterior walls. The exterior walls are just drilled directly into. The holes are made about 15cm above ground level. The holes are around 10mm in diameter.

The spacing of the holes will depend on the specific chemical mix used. The chemical DPC is then injected into the walls. The injection will either be done by hand or with a pump. Again, this depends on the exact type of DPC used. The holes will then be coated with a waterproof sealant for best results.

For interior walls, the plaster will need to be removed from the walls up to the level of the DPC. The injection process is then the same as for the external walls. Once the DPC is installed, the walls will be treated with a waterproof render and then re-plastered.

Installing a Drainage Channel

A trench is dug alongside the wall, usually only a spade’s width in size. The trench should drop to at least 4 courses of bricks below the DPC. The ditch is then filled with pebbles.

The pebbles should be no smaller than golf balls.

In an ideal world, the ditch should be sloped towards a drain or a soak away. Concrete can be laid at the bottom of the trench to help the water runoff.

Clearing out Cavity Wall

This is a fairly straight forward job. Around three bricks will be removed from the exterior wall and the cavity is then raked out. Once clear, the bricks are replaced.

Signs of Rising Damp

Rising damp can cause a wide range of effects so it is worth being aware of all the issues it can cause.

However, some of the effects can be hard to identify as being caused by rising damp, specifically, rather than any other form of damp. Depending on how and where the damp is rising, you may see some or all of these signs.

Yellow/Brown Tide Line Above the Skirting Board

As the damp rises up the wall, it will often carry minerals with it. These minerals will cause discolouration as they are carried up. If you see yellow or brown lines on the lower parts of your walls, then this is a fairly clear-cut sign of rising damp.

Salt Deposits

As the water rising up your walls is coming from the ground, it contains a lot of minerals. The damp might come and go depending on the weather and the heating in your home. When the water disappears, it’ll leave behind the salt that it brought with it.

You can spot these salt deposits on your walls. They are often white in colour and can be brushed off the surface of the wall. Salt deposits that are located on the lower parts of your walls are a definite sign of rising damp.

Damp Floor

If you have a spot on your floor that is often damp, and not as a result of spillages, then it is most likely caused by rising damp. These damp spots can come and go.

This is a result of the weather and your heating. However, if the same spot is repeatedly damp, then you should investigate as soon as possible. Rising damp that affects your floor can be expensive to repair.

Black Spots of Mould

Damp and mould go together hand-in-hand. If you have mould in your home, then it is likely caused by damp. It could be caused by any type of damp, so you will need to investigate.

If the mould you are seeing is located on the lower parts of your walls, then it is likely that rising damp is the culprit. However, because the damp from the walls can be evaporated by your heating, and then condenses elsewhere, you might find damp in other parts of your home.

Musty Smell

There is a very distinctive smell associated with damp. There is no special smell that marks rising damp. If you do smell damp in your home, you should examine to identify the cause.

Rotting Timber (floor joists, floorboards, skirting)

Rising damp can affect the woodwork in your home quite extensively. It can make the skirting boards warp and even begin to rot away.

If this happens, they will need to be replaced. It costs around £2 per metre of skirting board. If you need to refit the skirting boards in a whole room, it would cost around £250 for both supply and fit, based on a 4m x 3m room.

If the damp gets into the joists or the floorboards, then it can cause a lot of expensive problems. Signs that this has happened include warped flooring, flooring that gives a little underfoot or dropped floors (where one part of the floor is lower than the other when this wasn't previously the case).

If the joists rot, then they will need to be replaced. It can cost around £100-£250 per joist to have then replaced.

Wet Plaster

Plaster absorbs water so if there is damp coming up the brickwork it will also show on the plaster. New plaster becomes darker in colour. If the plaster has been painted, then you might be able to feel that the walls are damp or unusually cold to touch. Any form of damp can have this effect, but with rising damp, it will run up from the base of the wall.

Peeling Wallpaper

As the damp climbs up the wall, it can dissolve the wallpaper paste. The result is that your wallpaper may begin to peel off. If it happens at the joins in the paper, then you might be able to spot it easily.

If it happens in the middle of sheets, it can give a bubble-like appearance under the paper. Any water or damp in your home can have this effect. It is likely caused by rising damp if the effect is localised to the bottom of the wall.

Discoloured Wallpaper

If you have damp rising up the walls, it can change the colour of your wallpaper. All forms of damp or water incursions can cause this effect. If the lower sections of your wallpaper are a different colour, then it may be a sign of rising damp.

What Causes Rising Damp?

Rising damp is the name given to the damp that creeps up from the floor. It generally starts in the foundations.

The water travels up through the flooring and walls. There will always be some moisture in the ground below your house. Homes should be built with a damp-proof course (DPC). This is a waterproof layer that is built into the lower part of the wall.

Rising damp is when the moisture can enter your home and cause damage. There are several reasons why this might start to happen.

Rising Groundwater

Groundwater is just the water that is in the ground. The level at which this water sits can change. If there has been a lot of rain, then the groundwater can rise significantly.

If the groundwater rises too far, then it could become a problem. It might rise above the DPC and thus get into the house. If this is the cause of your rising damp problem, then it might come and go depending on the weather.

Older Building

The type of damp proof course used has changed over time. The type that is present in your home will depend on when it was built. Older methods include using a layer of slate, bitumen, or even hessian.

Some older buildings may not have any DPC, or the one they have might have become damaged or ineffective over time. Homes built before 1875 may not have a DPC. Home built in and around 1875 might have a DPC, but it could be poorly installed.

Slate DPCs were used in Victorian homes. These tend to fail as a result of movement. It causes the slate to crack.

Newer buildings use plastic or chemical DPCs. These are more resistant to time and should last much longer.

Leaking Pipework Under the Flooring

If there is a leaking pipe under the floor, there will be excess water. If this water rises above the DPC, then it will leach into the walls and continue climbing.

Even small leaks can end up having a devastating effect on your home. If you notice any signs of a leak that you can’t locate, you should get someone to investigate the problem. This is often covered by home insurance so it will only cost the amount of your excess on your policy.

Non-existent DPC

If the house is missing a DPC, then there is no protection against the damp. The water can move freely up the walls. There may be no DPC in some older homes. It became compulsory for new homes to be built with a DPC in 1875.

Houses built before this might not have a DPC. Any built after should have one, although early DPCs were sometimes poorly installed.

Debris in Wall Cavity or Subfloor

If there is debris inside the wall cavity or beneath the floor, this can let the water up the walls. It can act as a bridge for the water, which can then bypass the DPC.

Inappropriate Insulation

If you put insulation into your walls, then you need to choose breathable insulation. If the insulation causes moisture to collect, then it can cause damp and condensation problems.

Breathable insulation will allow any moisture to evaporate and will prevent any water from seeping into the walls.

It can also be a problem if the insulation is fitted badly. If the insulation overlaps the DPC, then it can provide a bridge for water to get past the waterproof layer into the house.

Plaster/render Overlapping DPC

If any material overlaps the DPC, then it will provide a route for water to enter your home. It is not uncommon for plaster or render to have been taken too far down on a wall.

This can happen if homeowners have done some DIY or if there was not enough care taken by the original builders.

Landscaping

If you have had landscaping done around your home, this could be the cause of rising damp. If any materials are piled up around the walls of your house, it can give the damp a route into your home. Any soil or rocks that comes above the line of the DPC will let moisture into your home.

Patios can also be to blame. If the patio comes above the DPC, it can act as a bridge for the water. Any permanent features on the outside of your house should stop three courses of brick below the DPC. Any higher than this and you significantly increase the risks of rising damp.

How Can Rising Damp be Prevented?

Rising damp can be expensive to fix. Not only do you have to stop the damp from entering, but you also have to fix the damage it causes.

There are a few steps you can take to protect your home from the effects of rising damp, but there is not much you can do to stop it from happening. You just need to be aware and catch it early.

Check DPC Regularly

You should be able to see the DPC from the exterior of your house. There should be a layer of different material visible in the masonry. It will be about 15cm above the ground.

Every now and then you can walk the perimeter of your home and just check that the DPC is unbroken all the way around. This is an easy way to get an indication of the state of your DPC.

Replace and Repair Damp-proof Membrane

An alternative to a DPC is a damp-proof membrane. You often find these under concrete slabs. It is just a different type of DPC. If the membrane becomes damaged over time, it will need to be replaced.

The price of the membrane will be around £125 per m². The fitting costs will depend on where it is located and what work is needed to access it.

Air Out Home

If you see any signs of damp in your home, whatever the cause, then you should take steps to ventilate your home. By letting your home ‘breathe’ it will allow the wet air to leave your home and give the walls and floor a chance to dry out. This will slow the damage being done by the rising damp.

Heat Every Room

If you have rooms in your home that are not often used, then it is tempting to turn off the heating and shut them up long term. However, this will allow any damp issues to grow. Turning on the heating will drive the moisture out of the walls and floors.

It doesn't need to be on all the time but making sure you heat every room in your home every two weeks will prevent the worst of the damage from occurring.

If you can see the signs of rising damp, then keep the heating on in the affected areas until you have taken action to prevent the damp getting in.

Check Any Leaking Pipework Under the Floor

If you have any reason to suspect that there is a leak under your floors, you should investigate immediately.

Most home insurance policies will cover the cost of getting a leak investigated, so you will only have to pay the excess on your policy. If left unchecked leaking pipes can cause a lot of expensive damage.

Check Drains

Keeping your drains clear will prevent them from backing up. If they do become backed up, the water level can rise above the DPC. If this happens, then you may on occasion have rising damp.

Check Exterior Masonry

You will be able to spot signs of rising damp on the exterior masonry of your home as well. It might even show up here first depending on how it is getting in.

Check to make sure that no organic matter or debris is collecting against your walls. If material piles up over the line of the DPC, then it will act as a bridge and allow water into your home.

What Happens if Rising Damp Goes Untreated?

Rising damp can cause extensive damage to a property. If caught early, the damage may be mostly to the appearance of the house.

For example, you might need to redecorate or replace skirting boards. The longer that rising damp is left untreated, the more damage it can cause.

Untreated, rising damp can begin to cause structural damage to your home. If it gets into floor joists, it can rot them away. Over time it will continue to climb up your walls, and in extreme cases can reach upper floors. If this happens, it could jeopardise the electrics in your home.

If you have rising damp, you will need to repair or replace the DPC. The longer you leave it untreated, the more you will have to spend to fix the damage. Repair costs could start from as little as £200 and rise as high as £20,000.

Types of Treatment for Rising Damp

There are a lot of suggested treatments for rising damp. Which one will work best for you will depend largely on the cause of your rising damp issue.

Some ‘treatments’ will only address the damage caused by the rising damp. They will not prevent the problem from returning. We’ve listed a few treatments below and have included the damp proof course cost too:

Install DPC

If you don’t have a DPC or yours has failed, then you will need to get this done. Replacing an old DPC is possible but costly, and a specialist job. The cost will vary depending on how many walls are affected and what sort of house you live in.

For one wall on a terraced house, it will cost around £300. For the whole of a detached house; it will cost around £2,100.

Pros

• ✔ Highly effective
• ✔ Long-Lasting

Cons

• ✖ Time Consuming
• ✖ Expensive
• ✖ Not possible with some types of brickwork

Chemical Injection

If you are missing a DPC or yours is ineffective then you can inject a damp-proof chemical into both the interior and exterior walls. This creates a DPC within the bricks.

There are a few different types but are all installed in the same way and have similar costs. The cost will depend on the number of walls in need of treating, and the type of house.

For one wall on a terraced house, it will cost around £490. For the whole of a detached house, this damp course cost around £4,700.

Pros

• ✔ Highly effective
• ✔ Long-lasting

Cons

• ✖ Interior walls will need to be re-plastered
• ✖ Skirting boards will need to be replaced
• ✖ Not possible in all types of masonry

Repointing

If the exterior wall of your home is showing signs of damp, then repointing can make it look new again. However, it will not fix the cause of the rising damp and will need to be done again if the root cause is not addressed.

The cost will depend on the area in need of repointing but for a single wall that only needs repointing at ground level, it will be around £310.

Pros

• ✔ Removes the external signs of damp

Cons

• ✖ Doesn’t fix the problem

Painting

If the rising damp has discoloured your plaster, then you can get anti-mould and anti-moisture paints to apply. The paint is easy to apply and will cost around £25 per tub.

Pros

• ✔ Easy
• ✔ Cheap

Cons

• ✖ Won’t fix the problem

Damp-proof Membrane

If you have a concrete floor and are getting damp spots in the floor and walls, then you may need to replace or install a damp-proof membrane.

The cost of the membrane will be around £125 per m². The fitting costs will depend on where it is located and what work is needed to access it.

Pros

• ✔ Effective
• ✔ Long-lasting

Cons

• ✖ The flooring may have to be taken up
• ✖ Dirty job

Un-bridging DPC

If you have exterior landscaping that is bridging the DPC, then you will need to remove it. It may also be worth laying paving around your home that will not collect and hold moisture. For example, instead of having soil against your home, lay a gravel path.

The costs for this will depend on how much landscaping needs moving and what you will replace it with. Costs will vary between £200 and £4,000.

Pros

• ✔ Can be a quick and easy job
• ✔ Effective

Cons

• ✖ Depending on the finish chosen can become expensive

Build a Drainage Channel

If you have paving against the house that is above the DPC and you don’t want to remove it, then you can install a drainage channel. It is an option with any treatment and can be a good idea if you often see standing water outside your home.

Costs will depend on the area needed to be dug, and the ground make up. You should expect costs in the range of £900 for a drainage channel around the whole house.

Pros

• ✔ Effective for given causes of rising damp
• ✔ No interior work is needed

Cons

• ✖ The finished look is not for everyone

Clear Out the Wall Cavity

If the problem is being caused by debris in the wall cavity, then you will need to remove this.

This involves taking out the external bricks, removing the debris and rebuilding the external wall. It will cost around £150.

Pros

• ✔ Easy job – a confident DIYer could do it

Cons

• ✖ May only be part of the problem

Can I Treat Rising Damp Myself?

Because of the scope of the job, it can be a good idea to leave it to a professional. This is especially true if the damage extends to floor joists. Physically installing a DPC, if done incorrectly, could cause damage to your home.

A lot of the DIY options involve hiding the signs of damp, not treating the root cause. If you choose to do this, it will end up costing more, in the long run, to fix the problem, as it won't go away. It will only get worse.

There are some aspects of the job that can be good DIY options. These can offer some money-saving options. Taking on the decorating, for example, is a good option which can save you £300-£400.

Another task that is not too daunting is to replace skirting boards, for a whole room, this could save you £250.

If you are an experienced and confident DIYer, you could try to do the plastering yourself. It is a skill that you develop with practice.

You are unlikely to get a perfect finish the first time you try, but if you are not in a hurry to get the room back, it can be an option to save you money. For a whole room, it could save you around £500.

Hiring a Damp Proofer Checklist

Because the causes of damp can be hard to discern your need to be able to trust your contractor. Here are some things to consider when picking your damp proofer.

• Look for a contractor with a lot of positive reviews, or who is happy to put you in touch with previous clients. If people have been ripped off, they will not be shy about saying so.
• Make sure that you chose a contractor that you can communicate well with. There are lots of hidden issues that can arise with this kind of work so you need to work with someone who will be upfront with you about problems, solutions and costs.
• Ask about a guarantee. Any good damp proofer will be willing to offer some sort of guarantee about their work.

FAQs

Sources

https://www.ukleakdetection.co.uk/faq/
https://www.which.co.uk/news/2018/03/how-to-avoid-spending-thousands-on-damp-proofing/
https://www.axa.co.uk/home-insurance/tips-and-guides/how-to-deal-with-rising-damp/
https://www.homebuilding.co.uk/how-to-deal-with-damp/
https://www.which.co.uk/reviews/damp/article/dealing-with-damp/rising-damp-treatments