Damp and mould

Information on how condensation occurs and how to deal with it, reducing the risk of dampness and mould growth in your home.

What is condensation?

Condensation is caused when water in the air comes into contact with cold surfaces, like walls and windows. As the temperature drops inside your home, the amount of water the air can hold falls and tiny droplets of water form on colder surfaces such as north facing walls, windows and hidden surfaces where there is little air movement. For example, inside or behind wardrobes and furniture.

As homes are upgraded with better insulation, draught proofing on doors and sealed double glazed windows, the amount of ventilation from draughts and heat escaping from your home is reduced. But, it  also reduces the amount of water in the air of your home escaping, which increases the risk of condensation.

You're unlikely to prevent condensation in your home completely. There is always some water in the air, even if you can't see it, but the amount is increased when cooking, bathing, and showering. Condensation is more noticeable on surfaces such as windows or tiles, but it can form on any surface and you may not realise until mould or rotting occurs.

Types of damp

  • Condensation damp - this occurs when a property cannot deal with normal levels of water vapour because of a lack of insulation, ventilation or heating, or a combination of all these things.
  • Penetrating damp - this occurs when water penetrates the fabric of a building from the outside.
  • Rising damp - this occurs when moisture travels up from the ground through the masonry.

Dealing with mould in your home

  • Wipe down windows and windowsills daily and dry the wet cloth in a well-ventilated area.
  • Wipe down walls and window frames with diluted bleach or a fungicidal wash.
  • Dry clean mildewed clothes and shampoo carpets.
  • Use a vacuum cleaner, not a brush, on dry mould.

Mould should not reappear once you resolve the causes of condensation.

If you are a tenant in council accommodation and the issue is not resolved you can book a non-emergency repair.

If you are renting from a private landlord and they are not taking responsibility to deal with the issue you can submit a complaint to the council.

Damp and mould issues on private land will have to be dealt with help from a private damp specialist.

Tips on preventing condensation, damp and mould

  • When cooking, cover saucepans, open windows or use an extractor fan to remove steam. Keep your kitchen door closed when cooking so steam can't spread around the property.
  • Drying clothes indoors puts a lot of moisture into the air. Dry laundry outside whenever possible. If clothes must be dried indoors, keep the room ventilated at all times. Try drying them in the bathroom with the door closed and the extractor fan on or window open. If your tumble dryer is not a self-condensing type, make sure its vent is funnelled  outside.
  • Keep a small window in your home slightly open to allow ventilation. If your windows have trickle vents, leave them open.
  • Keep the bathroom door shut when bathing to stop moisture getting to other, colder rooms.
  • Check that extractor fans in your bathroom and kitchen are working correctly.
  • Ventilate cupboards and wardrobes and don't pack them too full to allow air to circulate.
  • Leave space between large furniture (especially beds and sofas) and the wall to allow air to circulate.
  • Heat your home a little more. In cold weather, the best way to keep rooms warm enough to stop condensation is to keep some heating on a low setting all day long.


Page last updated: 31 Aug 2023