Condensation on Walls and How to Fight it

Condensation on Walls and How to Fight it

Why condensation forms on walls?

You perhaps already realise this, but condensation on walls occurs at ‘dew point’ resulting from the room air temperature being higher than the wall temperature, (it is effectively water vapour in the warm air turning to water because of the cooling effect of the wall). The longer the time the wall remains cold the worse the condensation will be – much the same as when you see condensation forming on the surface of a glass or bottle containing a chilled drink. Just a few degrees difference between wall and air temperature can be enough to cause condensation problems.

If the wall never warms up then the condensation can be a really bad  problem quickly leading to the formation of mould and allergy inducing spores – this is why condensation often forms on outside-facing walls and in ‘cold corners’.

A lot of household activities such as bathing, cooking, dishwashing, breathing (yes!) produce moisture – plants add to it as well. Relative humidity at 30 to 45% is healthy and pleasant for humans, but anything above 50% (winter time) can become a problem and lead to prolonged condensation on walls.


What can be of help to fight condensation on walls?

A layer of Wallrock Thermal Liner means that the wall surface temperature, which is effectively the layer of Wallrock Thermal Liner, warms up and equalises with the room air temperature quicker. This prevents the cold walls from coming into contact with the warm room air and stops the condensation on the walls forming thereby significantly reducing the chances of mould formation.

Wallrock products are breathable too and allow any moisture in the walls to move through naturally.


Part of the problem lies in the lack of or ineffective ventilation. We would suggest that you check your wall vents ensuring they are not blocked. It might be advisable that you get a dehumidifier to draw excess moisture from the air – this is especially useful during the winter months. It doesn’t have to be on all the time (in fact that would cause the air to be too dry in the house) and only come on when needed. Some of the modern dehumidifiers provide you with the reading of humidity level in the air, which helps greatly.


  1. Mr Ali

    Hi Can I apply wallrock thermal liner over existing wall paper painted or do i need to remove it

    • Apologies for the delay in replying. You can apply wallrock thermal liner over existing wallpaper as long as the wallpaper is stuck to the wall well i.e. it’s not coming off at the seams or corners – this applies to pretty much any work where you’d be over laying an existing wallcovering. If you apply adhesive over loose parts of the wallpaper it will loosen it further and could cause the thermal liner to come off with the wallpaper. I hope this helps.

  2. We have just put rockwall fiberliner on our walls can you use vinyl wallpaper on top???

    • OnWall

      Yes, you can put vinyl on top. Suggest you use read-mix wallpaper paste though.


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