Damp and mould

A damp house can cause timber frames in windows and doors to rot and can lead to respiratory health issues.

Some damp is caused by condensation. Condensation is where water collects as droplets on a cold surface when humid air comes into contact with it. You notice it in the bathroom after a shower/bath on mirrors or tiled surfaces.

Condensation often occurs during cold weather and in areas of the home where there is little ventilation.

Is your dampness condensation?

Is there a tidemark? If there is a tidemark the dampness is not caused by condensation. It could be a leak or rising damp. 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 your home is damp for any of these reasons it may take weeks of heating and ventilation to dry out. Hiring a dehumidifier will help.

If you do not think the damp comes from any of these causes, then the likely cause is condensation.

How to minimise condensation

Ordinary daily activities produce a lot of moisture often very quickly.

You can reduce the moisture produced by trying the following actions:

  • cover boiling pans when cooking.
  • avoid paraffin and portable gas heaters as these add moisture to the air
  • dry washing outdoors or in the bathroom with the door closed and a window open or fan turned on.
  • vent tumble dryers using proper vent kits or use a self-condensing type
  • keep your home warm to reduce moisture
  • ventilate to remove moisture

Do not:

  • block permanent ventilators
  • completely block chimneys. Instead, leave a hole about two bricks in size and fit a louvred grille over it
  • draught-proof rooms where there is condensation or mould
  • draught-proof a room where there is a cooker or a fuel burning heater eg a gas fire
  • draught-proof windows in the bathroom and kitchen.

Dealing with mould growth

First treat any mould that you may already have in your home. If you then deal with the basic problem of condensation, mould should not reappear.

Mould on washable surfaces can be removed with a fungicide solution readily available from supermarkets. Other items such as fabrics can often be washed or dry-cleaned, although this may not always remove the mould staining.

After treatment, redecorate using a good quality fungicidal paint to help prevent mould recurring.

The only lasting way of avoiding severe mould is to eliminate dampness.