Black mould on walls

Damp Walls

Damp walls in and around the house are a big problem facing homeowners. It is important to find the source of the problem and treat it as soon as possible. There are many different types of damp that can be found on walls, meaning the way to treat a particular damp problem differs too.

Damp patches on the internal walls of your home can be a real pain as they are not only visually unappealing to look at but also the moisture and dampness on walls can cause mould.

Mould can have implications for your health especially for sufferers of asthma and allergies. Having cold damp internal walls can also make your room feel colder and more uncomfortable to occupy.

How to Know If You Have Damp Walls?

One way of finding out if damp is present on walls is by using the back of your hand against the wall.

Although this isn’t the most accurate way to ascertain the severity of the issue, by feeling the damp area compared to a dry area on the wall it can give you a good indication of how bad the damp on your wall actually is.

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Damaged wallpaper as a result of damp

Identifying Condensation on walls

Condensation forms by the moisture been absorbed into warm atmosphere of a property, then, as the property cools down, the excess moisture condenses on cold surfaces such as on windows or windowsills.

The reasons for this occurring can be numerous – for example it could be down to the fact that there are cracks in the wall allowing draughts and air flow into the property, or as a result of no constant air flow of ventilation in the property.

Penetrating damp on walls

Identifying Rising Damp on walls

Rising damp will only affect walls on the ground floor of a property. Usually, there are horizontal brown or discoloured marks that can be seen up to 1 meter in height on interior walls, these are otherwise known as ‘Tide Marks’.

The signs of a rising damp issue can also be felt through the fabric of the wall with the bubbling of the plaster that is caused by the continual expansion and contraction of salt crystals drawn from the ground.

Rising damp on walls

Identifying Penetrating Damp on walls

Penetrating damp occurs on the exterior of a property and can cause serious damage to the building if not treated correctly. You may notice damage to the internal walls of the property with watermarks being found on the masonry.

Where there has been heavy rainfall, the rainwater usually evaporates out of the brick. In some cases though, the moisture falls to evaporate though and is then allowed to pass through the inner surface of the wall.

How to Treat Damp On External Walls?

The most common form of dampness on the external walls of the property is penetrating damp. This form of damp is caused predominately where there is heavy weather and there are property maintenance issues. Treating penetrating damp on walls can be carried out through the following methods:

Penetrating Damp:

  • Repairing masonry defects e.g. cracks in walls, faults doors. If there are any problems then this will need to be fixed with a suitable render. Using a masonry protection cream can help prevent rain penetration.
  • Remove excess moss and leaves from roofs and gutters. If leaves and plants start to build in the rainwater goods then this can lead to leaks at the property.
  • Improve the heating of the property and insulate the cold walls.






Rising damp can also form on the external walls of the building and is usually caused by having a damaged damp proof course. The following treatments are listed for damp proofing walls :

Rising Damp:

  • Installation of a Damp Proof Course (DPC) and Damp Proof Membrane. This is an expensive method of treating the damp problem will prevent any further deterioration to the building and will stop any further expenses for preventing rising dampness in the near future.Osmotic Damp Proofing





Treating Damp On Internal Walls

Having damp patches on the internal walls of the property is most likely to occur from condensation. When warm damp air condenses onto cold surfaces such as walls, mould can start to develop. The most sufficient method of stopping damp in the interior walls of the house and therefore preventing mould growth from occurring is through improving the ventilation throughout the property. The below methods are ways of curing damp on internal walls.

Envirowise EnergySaver Positive Pressure Ventilation


  • Improving the ventilation e.g. add kitchen and bathroom fans. Allow the fan to run for a long period of time to allow the moisture to be cleared from the room.
  • Use a Condensation Mould Kit to remove mould from walls and surfaces. Once the mould treatment has been applied then this can be painted with a damp seal which ensures that the staining will not seep through the emulsion once this has been completed.
  • Improve the heating of the property and insulate the cold walls


Damp in walls can also occur from rising damp. If groundwater rises up the inner walls of the property this can cause damage to skirting boards, plaster peeling off walls and black mould growth. Treatment for rising damp can be achieved by having a damp proof injection course or a damp proof membrane.

Do you have Damp Walls in your Property?

It’s important that damp in your property is correctly identified to ensure the right treatment is carried out.

Timberwise has over 5 decades of experience providing solutions to all your damp problems. Find out what happens during a damp survey which might give an insight into the start of the process of treating any of your damp issues. Call our experts today on 0800 288 8660 or click below to arrange a survey online.