Damp, mould and condensation

Condensation and mould

Condensation is the most common cause of dampness.

Condensation is caused by water vapour or moisture in the air, inside the house, coming into contact with a colder surface, such as a window or wall. The drop in temperature causes water to form on the surface. This water may then soak into the wallpaper, paintwork or plasterwork.

Mould spores are invisible to the naked eye but are in the air around us all of the time, and will quickly grow into a visible covering on surfaces where condensation has formed.

Condensation mainly occurs during the colder months, whether it is rainy or dry outside. It is usually found in the corners of rooms, north facing walls and on or near windows. It is also found in areas of little air circulation such as behind wardrobes and beds, especially when they are pushed up against external walls.

Mould is almost always seen with this type of dampness and is normally the first symptom. All homes are affected by condensation at some point, however certain activities can make the problem worse. Good practices can help reduce condensation in your home.

Condensation and mould growth are often due to lifestyle habits and activities that can be reduced or managed better by the householder.

Cooking, washing, drying clothes indoors, even breathing, all produce water vapour that can only be seen when tiny drops of water (condensation) appear on colder surfaces such as walls, windows, ceilings or mirrors and often unseen on clothing, shoes and furniture.

The amount of condensation in a home depends upon a number of things, most importantly:

  • how much water vapour is produced by the actions of its residents
  • how cold or warm the property is
  • how much air circulation (ventilation) there is
  • how well the property has been insulated

Simply turning up the heating will not sort out the problem, this may only temporarily reduce condensation. All factors may need to be looked at to reduce the problem.

The first sign of a problem is often water vapour condensing on windows and other cold surfaces, which then takes a long time to disappear. This allows the surfaces to become damp resulting in mould growing on these damp areas.

By dealing with the causes of condensation you will also be dealing with the problem of mould.