Damp Proofing: Find the Right Solution for Your Home
Damp can be frustrating because very different problems can look surprisingly similar.
A dark patch above the skirting could be rising damp, penetrating damp, a plumbing problem or even condensation. Treat the wrong cause and there's a good chance the damp will simply return.
That's why we recommend identifying the source first and treating it second. Once you know where the moisture is coming from, choosing the right damp proofing product becomes much simpler.
Rising Damp, Penetrating Damp or Condensation?
Here's a useful starting point.
Rising damp is moisture moving upwards from the ground through porous masonry. Typical signs include damp and deterioration at the bottom of ground-floor walls, a visible tide mark and white salt deposits. The affected area is generally concentrated at low level. Rising damp is also frequently misdiagnosed, particularly in older properties, so it's worth checking the cause carefully before installing a new DPC.
Penetrating damp is moisture entering through the building from outside. Common causes include damaged pointing, cracked render, leaking gutters or roofing defects. Unlike rising damp, it can appear at different heights and will often become more noticeable during or after wet weather.
The first job is to repair the source of the water. Depending on the surface and situation, an appropriate breathable masonry water repellent can then help protect exposed masonry against further rain penetration.
Black mould around windows, external corners or other cold surfaces is more commonly associated with condensation and excess indoor humidity than rising damp.
If mould is your main problem, take a look at our Mould Control range instead.
Treating Rising Damp with DPC Injection Cream
If you've established that you have rising damp caused by a missing or ineffective damp proof course, installing a chemical DPC can provide a practical solution.
Our Dri-Wall DPC Injection Cream is injected into the mortar bed of the wall, where it penetrates the masonry and creates a water-repellent barrier to help prevent moisture continuing to rise.
For DIY projects, our kits give you the products and equipment you need in one box, with no powered injection pump required.
32m Mini Kit: ideal for a single affected wall or smaller project.
80m Professional Kit: designed for larger jobs such as several rooms or a ground floor.
Not sure how much DPC cream you need? Tell us the length and thickness of the wall and our team can help you work out the right quantity.
Don't Forget About Re-plastering
Treating the source of rising damp is only part of the job.
Moisture and salts already present within the wall can continue to affect the surface while the masonry dries. This is why simply covering an affected wall with ordinary plaster can lead to further deterioration.
For walls affected by residual salts, use a suitable salt-resistant renovating plaster, such as Limelite, as part of the remedial specification. Once everything has dried sufficiently, finishing with an appropriate breathable coating can also help the wall release residual moisture.
Getting this stage right helps protect the finish you've just worked hard to restore.
Damp Proof Paint, Membranes and Tanking
Not every damp problem requires a new damp proof course.
For walls and floors that need a waterproof barrier, we offer several different options depending on the level of moisture and where the product is being used.
Damp Guard Damp Proof Paint creates a liquid-applied barrier over suitable concrete, brick and rendered surfaces. It can be useful for selected wall and floor applications where a continuous coating is required.
For larger areas, damp proof membranes provide a physical barrier that can form part of a wall or floor waterproofing system.
For cellars, basements and other below-ground areas, where water pressure can be more demanding, a properly specified tanking system is generally required.
If you're unsure which system suits your project, speak to us before ordering. A quick conversation can prevent you buying a product that isn't designed for the job.
When Should You Get a Damp Survey?
Many damp proofing jobs can be tackled by a capable DIYer, but diagnosis matters.
If you suspect rising damp but aren't certain, an independent damp survey can be money well spent. Rising damp is known to be over-diagnosed, particularly in older buildings, and organisations including the Society for the Protection of Ancient Buildings caution against unnecessary DPC installation.
A good survey should consider the whole building rather than relying on a single moisture-meter reading.
For more complex problems, particularly older or traditionally constructed buildings, getting specialist advice before starting work can prevent unnecessary treatment.
Why Choose Kingfisher?
Made in the UK. Backed by people you can actually talk to.
We're a family-run business and have been manufacturing building protection products in the Lake District since 1988.
Because we manufacture our own products, you're buying from a team that understands how they're made, how they should be used and which product is appropriate for different situations.
And if you're unsure? Ask us.
Our technical team can talk through what you're seeing and help you choose the right treatment before you spend your money.
If damp has also affected timber, explore our Dry and Wet Rot Treatments for products designed to deal with associated timber decay.
Frequently Asked Questions
How can I tell if I have rising damp?
Look for a combination of symptoms rather than relying on one sign. Rising damp generally affects the lower part of ground-floor walls and can produce a visible tide mark, deteriorating plaster and white salt deposits. Other moisture problems can produce similar symptoms, however, so it's sensible to confirm the cause before installing a new DPC.
Do I need to re-plaster after damp proof course injection?
Often, yes. Existing plaster may contain moisture and salts accumulated before the new DPC was installed. Where contaminated plaster needs replacing, use a suitable salt-resistant renovating plaster or another compatible remedial system rather than simply covering the affected area with ordinary plaster.
Will damp proofing get rid of black mould?
It depends on what is causing the mould. Black mould around windows, cold external walls and room corners is commonly associated with condensation and high indoor humidity. In those situations, ventilation, heating and moisture management need to be addressed alongside appropriate mould treatment.
How much does damp proofing cost?
That depends on what's causing the damp, how large the affected area is and which treatment is required.
The best way to avoid unnecessary expense is to diagnose the problem before buying anything. If you tell us what you're seeing, where the damp appears and roughly how large the affected area is, our team can help you work out what you're likely to need.
