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Damp and condensation

Damp can cause mould on walls and furniture and make wooden window frames rot. Damp housing encourages the growth of mould and mites, and it can increase the risk of respiratory illness.

Some damp is caused by condensation. 

What is condensation?

There is always some moisture in the air, even if you can’t see it. If the air is colder, it can’t hold all the moisture and tiny droplets of water appear. This is condensation.

You notice it when you see your breath on a cold day, or when the mirror mists over when you have a bath or shower.

Condensation occurs mainly during cold weather, whether it is raining or dry. It does not leave a 'tidemark'. It appears on cold surfaces and in places where there is little movement of air. Look for it in corners, on or near windows, in or behind wardrobes and cupboards.

Is it condensation?

Condensation is not the only cause of damp. Damp can also come from:

  • leaking pipes, wastes or overflows
  • rain seeping through the roof where a tile or slate is missing, spilling from a blocked gutter, penetrating around window frames, or leaking through a cracked pipe
  • rising damp due to a faulty damp course or because there is no damp proof course.

These causes of damp often leave a 'tidemark'.

If your home is damp for any of these reasons, it may take weeks of heating and ventilation to dry out. Hiring a humidifier will help.

If your home is newly built, it may be damp because the water used during its construction (for example, in plaster) is still drying out.

If you do not think the damp comes from any of these causes, it probably is condensation.