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Advice on condensation/mould

How to treat and deal with it

What is condensation

There is always some moisture in the air, both inside and outside your home. The warmer the air is, the more moisture it can contain. As air cools it stops being able to hold all the moisture and this turns into tiny droplets of water, which we call condensation, this can lead to black mould growth which appears on cold surfaces and in places where there isn't much movement of air.

Every household will suffer from condensation at some time. This is usually when we produce a lot of steam or moisture, such as when we cook, or we have a hot bath or shower. We also produce moisture when we breathe. This can be as much as a pint while we sleep, which is why bedroom windows are often misted up in the morning after a cold night.

Condensation is not the only cause of damp. Check for:

  • leaking pipes, wastes or overflows
  • missing slates or roof tiles that might be allowing rain in
  • blocked gutters that might make the rain water overflow down the brickwork
  • water penetrating in around your window frames

How to avoid condensation

Condensation can cause mould on walls, ceilings and even clothes in cupboards. It can also make wooden window frames rot. By following these three simple steps you can help reduce condensation in your home.

1. Produce less moisture:

  • Close the kitchen or bathroom doors when cooking or bathing to stop warm moist air spreading throughout your home
  • Dry your washing outside - if you have to dry it inside, put it in the bathroom with the door closed and the window open or fan on
  • Vent your tumble dryer to the outside, unless it is self-condensing
  • Put some cold water into the bath before you fill it with hot water
  • Wipe condensation from windows and window sills whenever it occurs
  • When you cook, choose the right size pan for the food and always keep the lids on. Only fill kettles with the amount of water you need, and don't leave them boiling. This will also help you cut down your fuel bills

2. Ventilate your home

  • Keep a small window or trickle vent open when you use a room
  • Open your bathroom or kitchen window when using either of these rooms and always use mechanical ventilation if you have it
  • Don't block up air bricks or vents, especially providing air to a gas heating appliance
  • Leave a space between your furniture and the wall, and try to avoid positioning it against an external wall at all if you can

3. Heating, insulation and draught proofing your home

  • Leave background heating on throughout the day in cold weather, even if noone is at home
  • Close your curtains at dusk to stop heat escaping through the windows - this could save you up to £15 a year
  • Draught proof your letterbox and keyhole - fit a nylon brush seal or a spring flap, and put a cover over the keyhole

What initial steps to take to deal with condensation and mould

Treat the mould already in your home. (If you then deal with the basic causes of condensation, mould should not re-appear). To kill and remove mould:

  • Wipe down walls and window frames with a fungicidal wash which carries a Health and Safety Executive ‘approval number’ (available from most DIY shops)
  • Follow the manufacturer’s instructions precisely
  • Dry clean mildewed clothes, and shampoo carpets. (Disturbing mould by brushing or vacuum cleaning can increase the risk of respiratory problems)

After treatment, redecorate using a good quality fungicidal paint to help prevent future mould growth. Note that this paint is not effective if overlaid with ordinary paints or wallpaper.

The only lasting way of avoiding problematic or severe mould is to eliminate the dampness caused by condensation.

Top tips to reduce condensation in the home

  • Produce less moisture
  • Cover pans
  • Dry clothes outdoors
  • Vent your tumble dryer to the outside
  • Avoid using paraffin or flueless bottled gas heaters
  • Ventilate to remove moisture
  • Ventilate whenever someone is at home
  • Increase ventilation of the kitchen and bathroom when in use and shut the door
  • Ventilate cupboards, wardrobes and blocked chimneys
  • Insulate and draught proof
  • Insulate the loft and cavities
  • Draught proof windows and external doors
  • Consider secondary glazing
  • Heat your home a little more
  • If possible, keep low background heat on all day during Winter time