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Can i paint the exterior walls to solve a damp problem?

Posted by: on 03/03/2022


You must, first of all, understand that the breathability of traditional structures and materials is important. Yes, external walls become wet during periods of rain but when they are left exposed the water will simply evaporate from the wall during the drier periods of weather. When external elements of the property are sealed or covered over with impervious materials such as cement renders, paints, and plastics it can lead to trapped moisture and condensation. This can lead to consequent deterioration and disrupt performance as well as exacerbating internal damp issues.

During periods of prolonged rainfall, the external elevations will become saturated and during drier spells, the wall will dry from top to bottom (the bulk of the residual moisture will be at the base of the wall due to the natural effects of gravity) but when the external elevation is painted with an impervious coating it severely restricts the evaporation of moisture from the base of the walls on the external elevations and therefore encourages the moisture to migrate to the inner wall surfaces which in turn exacerbates the damp levels on the internal walls. Painting an external wall will rarely if ever resolve an ongoing damp issue affecting the internal wall surfaces and in reality, it will exacerbate the problem.

The ideal solution would be to remove the external decorative coating to allow moisture to evaporate naturally from the external surfaces but this may not be practicable in some circumstances so you will need to get professional advice as to how you deal with the damp issues internally.

Penetrating Damp affecting the internal wall surfaces.
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