How To Damp Proof Your Walls

How To Damp Proof Your Walls
A musty smell in your home may be caused by more than just old age. Wet walls are often the culprit.

If you notice damp or wet walls in your home, immediate action should be taken to remedy the situation. Failure to do so may result in damaged walls or black mould.

Damp walls are caused by an array of problems. Some of the most common culprits include:

  • Penetrating damp, often caused by faulty roofing, damaged downpipes, or leaky gutters.
  • Rising damp, which is noted by dark patches on the walls that are damp to the touch.
  • Condensation, often caused by poor ventilation.
  • Pipe leaks.
  • Foundation damage.

If any of these problems are noted, they should be addressed as soon as possible to stop further damage. Consider having your roof, plumbing, boiler, and foundation inspected on an annual basis to catch any problems before they get worse.

No matter the reason for damp walls, they need to be repaired right away. Of course, rather than wait until damage happens, damp proofing your walls beforehand can save you a lot of money and headaches in the future.

Damp Proof Membrane

You can protect a wall that is susceptible to wetness by installing a damp proof membrane. This highly flexible material is fashioned out of high density polyethylene, which protects against both water and salts.

The material is designed to prevent damp walls by allowing moisture to evaporate in small, egg-shaped cavities.

Securing a damp proof membrane is relatively simple. Remove any plaster from the wall. Cut the membrane to the correct size. Use a drill to secure the membrane on the wall and to ensure a tight fit. The membrane should then be adhered in place using specially designed fixing plugs.

Damp Proof Paints

Damp Proof Paints

Damp proof paints are very popular with those who are looking for an easy way to prevent moisture in a humid room. The paint should be applied directly to the background substrate.

Once it dries, cover the paint with plaster. This is the most effective way to keep moisture at bay with paint.

If you decide to paint directly over plaster with damp proof paint, you will still get some protection. However, be aware that the surface degrades over time. Damp proof paint should never be applied to surfaces that have been damaged by salt, as it will not properly adhere.

Our 5 Recommended Damp Seal Paints:

Our RatingProductNameTypical PricePerformanceValue For MoneyView On Amazon
#1Thompson Stain Block Damp Seal

Thompson TDS25L 2.5L Damp Seal

£11 per litreExcellentOutstandingCheck Stock
#2Polycell Damp SealPolycell One Coat Damp Seal£17 per litreExcellentGoodCheck Stock
#3Polar Damp Seal PaintPolar Anti Damp Paint£23 per litreExcellentAverageCheck Stock
#4Ronseal One Coat Damp SealRonseal One Coat Damp Seal£11 per litreGoodOutstandingCheck Stock
#5Rustins One Coat Damp SealRustins One Coat Damp Seal£31 per litreOutstandingPoorCheck Stock

Tanking Slurry

For walls that are made from bricks, masonry, or concrete, a layer of tanking slurry may be used to prevent moisture. The slurry creates a fully waterproof layer when it is applied to masonry.

Prime the surface with a salt inhibitor. Two coats of tanking slurry should then be applied to the wall. Allow 4-8 hours of drying time between each coat. Tanking slurry is very effective in basements, but it can also be used on other internal walls.


Replastering walls

If the damage to the wall is minor, it may be possible to damp proof the area by removing the plaster and applying new render. Use a water-resistant render to ensure the area is protected.

Any moisture that is left in the walls will dry out naturally, and the finish will stay dry.

Special Situations

While most damp walls are easily remedied with one of the stated procedures, there are some special situations which require more care, including:

  • Cavity Walls
  • Below Ground Walls

Preventing Moisture

It’s possible to prevent damp walls in many instances. Homeowners should routinely check areas around their home where moisture is the most common, including:

  • Ensure roof is in good working order.
  • Check downspouts, and make sure they are flowing away from the foundation.
  • Keep the property well-maintained.
  • Remove any large plants that are growing too close to the property, as the roots may damage the foundation or pipes.
  • Monitor for signs of rising damp.
  • Improve the ventilation of your home to reduce condensation.
  • Check the sealing around doors and windows.
  • Keep vegetation away from masonry and render.
  • Check boiler, taps, and pipes for leaks.

Damp walls can cause many problems in a home. As soon as dampness is suspected, it’s time to determine the source and repair the walls.

Dry out the walls as soon as possible and damp proof them using one of the recommended methods to ensure your home stays as dry as possible.

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