Rising damp treatment carried out on external wall of property

Rising damp treatment

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How to treat rising damp

Rising damp is a well known but relatively uncommon form of damp that impacts walls on the ground floor of buildings.

It can be a concerning issue for homeowners as it has the potential to cause unsightly staining, damage to fixtures and fittings and can provide the moisture necessary for timber decay and rot.

If you suspect your property is suffering from rising damp, and requires rising damp treatment, then this expert guide will let you know everything you need to know about the identification, diagnosis and successful treatment of rising damp.

Keep reading to find out more but if you want to get a surveyor out to your property as soon as possible you can book an appointment by calling us or clicking the button below.


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When is rising damp treatment necessary?

Rising damp treatment is necessary when the failure or bridging of a damp proof course allows moisture to rise up from the ground through a process called capillary action leading to damage to exterior and interior walls.

Why do damp proof courses fail?

Damp Proof Courses (DPCs) can be made from many different materials from slate to silicone. Over time some of these physical courses can break down and fail.

DPCs can also be “bridged” this means the DPC has been compromised and can allow moisture to bypass the barrier. Bridging can occur in many ways including renovations like a raised flowerbed or driveway that are higher than the DPC or a build up of absorbent material in a cavity wall.

Diagnosing rising damp: The damp survey

Before discussing the treatment of rising damp, it is crucial to obtain an accurate diagnosis. One of the reasons rising damp is such a controversial topic in the property preservation industry is that other damp problems such as condensation or penetrating damp are often misdiagnosed as rising damp. This has led some people to mistakenly believe that rising damp is a myth.

For this reason a damp survey by an accredited and qualified expert is essential to accurately diagnose the damp problems in your property and identify if they are in fact caused by rising damp.

The following signs can be rising damp:

  • Tide mark damp staining on walls
  • Salt deposits on internal walls
  • Blistered and peeling paint
  • Stained or mouldy wallpaper
  • Rotten and decaying timber (skirting board or flooring)
  • Musty damp odour

However, these can all be signs of other causes of dampness such as condensation and penetrating damp. It is these shared symptoms that can make rising damp an easy condition to misdiagnose.

You can read more about our survey process on our designated damp survey page.

How to treat rising damp in walls

Rising damp can be controlled by the installation of a new damp proof course. In some instances  it may be possible to install a new physical damp-proof course, however for the majority of remedial damp proof courses the installation of a chemical damp proof course is the most economically viable option.

A chemical damp proof course is designed to seep into the brickwork to prevent moisture rising up through the bricks by capillary action and causing rising damp. The active component, silane, lines the capillaries before drying. This creates the water repellent barrier.

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Do I need a damp proof course?

If the failure, or a lack of, an existing damp proof course is correctly diagnosed then the only method to control rising damp is a new damp proof course.

Where an existing damp proof course has been bridged it may be possible to remove the bridge and return the existing damp proof course to efficiency without the need for a new installation. However, some consideration must be made for the possibility of salt contamination to plaster work.

Where it is not possible to remove the bridge then the installation of an internal waterproof barrier and an appropriate remedial damp-proof course at a suitable height should be considered.

How is a damp proof course installed?

The first step to installing a DPC is undertaking any preparation works,this may involve removing salt contaminated plaster, any fixtures and fittings such as skirting boards and radiators to provide access.

Once any preparation work has been done the technician will drill holes horizontally around 120mm apart into the wall mortar joint approximately 150mm above the external ground level.

The damp proof injection cream works as the liquid silane and siloxane components spread by diffusion into the masonry and react with the available silica to form a waterproof barrier. This means the cream can be injected at intervals to leave a completely damp proofed mortar course.

Once installed, damp proof injections should remain effective for decades; this is why Peter Cox offers long-term guarantees on the majority of our rising damp treatments.

Can you put a damp course in yourself?

While it is possible to do some DIY damp proofing, professional installers have a meticulous process when injecting a remedial damp proof course to make sure the job is done properly.

The reason it is recommended that an approved contractor inject a damp proof course is because there are many errors that need to be avoided to successfully inject a damp proof course. These include:

  • Holes drilled directly into the brick or into stone instead of following the mortar line
  • Injecting a needless damp proofing course where an effective DPC already exists
  • Injection into a damaged or poor quality mortar joint that needs repaired first
  • Injecting when there is a bridged cavity wall. These fill up with debris and eventually allow moisture to pass across the damp proof course.

To avoid any of the issues listed above, Peter Cox install damp proof courses to BS 6576:2005 – the British Standard code of practice for the diagnosis of rising damp in walls of buildings and the installation of chemical damp proof courses.

What is a damp proof membrane?

Damp proofing membrane is typically a studded waterproof sheet made from polyethylene or polypropylene. British Standards dictate that the sheet should be at least 1200 gauge or 0.3mm. These materials are very strong and extremely flexible. This means they can cope with structural movement, making them a long-lasting and reliable damp proofing solution.

Damp proof membranes are not always necessary in rising damp treatment but they are sometimes installed after the injection of a damp proof course as they provide an excellent water resistant key for new plaster work.

Peter Cox provides damp proofing membranes that have a mesh on one side for direct application of render and plaster or plasterboard. This versatility makes damp proof membrane an excellent option for homes and many commercial properties where maintaining an aesthetically pleasing finish is desirable.
Damp proof membranes also ensure that new plaster is kept away from residual salts or contaminants in the brickwork from the original rising damp problem.

Replastering after rising damp treatment

Although the wall has a new damp proof course, the walls will be wet and may contain hygroscopic salts. Therefore replastering materials need to create a barrier preventing salts from affecting the new plasterwork. This is done by using salt retardant plaster, meaning the existing salts in the wall won’t be able to migrate through the plasterwork.

How much does rising damp treatment cost?

There is little point in offering an average cost for rising damp treatment. The price is dependent on the severity of the problem and any structural factors specific to the design of your property. Naturally, if the rising damp problem is localised to one small area on a particular wall, the damp proofing cost would be less than if all ground level walls were affected.

No reputable firm would be able to provide an estimate of price without first sending a qualified surveyor to attend the property. This is to ensure rising damp is in fact the culprit and not condensation or rain penetration. If you think you may have identified rising damp then you can discuss it with our contact team by giving your local branch a call, or book a survey online.

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Is rising damp treatment messy?

Installing a remedial damp proof course and removing salt contaminated plaster can of course result in dust and debris entering your home. Our specialist damp treatment teams are equipped with top-of-the-line dust extraction units from Hilti UK, along with a vacuum and plastic sheeting for flooring. This is part of our commitment to leaving your home in a safe and clean condition ready for you to inhabit straight away.

Is rising damp covered by insurance?

Unfortunately, the majority of buildings and contents insurance policies consider rising damp to be the result of gradual deterioration and therefore will not cover you for damage caused by rising damp.
However, Peter Cox does offer rising damp insurance if this extra peace of mind is something you would be interested in for your home or commercial property.

Is rising damp treatment guaranteed?

For a typical treatment for rising damp, you can be assured that it will carry the benefits of our twenty year guarantee. This provides the security and peace of mind that comes from knowing that should something go wrong with our damp proofing treatment, then we will be there to put it right.

On top of our guarantees and optional rising damp insurance, we go the extra mile to make sure our customers feel secure knowing that we are a rising damp treatment company that you can absolutely trust. We are a Which? Trusted Trader and rated ‘Excellent’ on Trustpilot with over 2,000 reviews. As leaders in the damp protection and property care industry we set the standards for excellence for professionalism and expertise in the industry.

Contact the rising damp treatment specialists

With over 70 years experience our qualified surveyors are specialists in diagnosing rising damp and prescribing the correct damp proofing solution to remedy the problem. Our professional surveyors will also lookout for any potential wet rot or dry rot issues that have occurred as a result of the damp problem and will also recommend solutions to fix damage caused to internal walls, plasterwork and other building materials

If you are happy with our recommendations after the initial consultation, our highly qualified and locally based team of technicians can carry out all damp proofing and repairs to your property. This ensure that when we are finished your property is left clean, safe and dry

Contact Peter Cox today by giving us a call or click the button below to book a survey online.

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Next Steps

*Survey enquiries for your local branch will be directed to our dedicated central survey control teams across the UK. Calls to 0800 and 0808 numbers are free unless you are calling from a business phone, in which case the rate will be set by your provider.