Combatting Damp and Mould

Page updated on: 15/11/2023

When you see a black spot mould, you may think that you have a leak or rising damp, but in most cases this is caused by condensation and can be easily removed.

What is Condensation?

There is always moisture in the air, even if you can't see it. Warm air holds on to moisture, cold air doesn't. Moisture in the air will form condensation (droplets of liquid water) when it comes into contact with a cold surface such as a window. We all get condensation on our windows from time to time, but this isn’t necessarily a problem if it clears up quickly.

Condensation occurs particularly in cold weather - even when its dry outside. It is seen most on windows and mirrors when you have a bath or shower but can can form on any cold surface, including walls. Condensation is worse if there is no ventilation.

When condensation builds up on surfaces, and they’re damp for some time, it can cause mould to grow.

So how do you spot condensation?

  • Streaming windows and walls
  • Damp areas can appear on walls, especially behind furniture and in corners
  • Wallpaper can start to peel
  • Mould growth, usually black mould, starts to appear on window frames, walls and ceilings
  • Soft furnishings and fabrics become prone to mould and mildew
  • There is a constant musty damp smell in the property

Key points to prevent condensation and mould

  • You can also try to reduce the moisture in your home, by
    • Hanging washing outside to dry, or in the bathroom on a drying rack with the door closed. Never dry washing on radiators.
    • If you use a tumble drier, make sure it vents outside
    • Cook with pan lids on and use the extractor fan
    • When filling your bath, run the cold water first to reduce steam
  • Instead of opening your windows, during the colder Autumn or Winter months, leave all your window trickle vents open.
  • Keep the kitchen and bathroom doors closed when cooking and showering/bathing and leave a window open for 20 minutes after.
  • Keep furniture slightly away from walls to increase air flow.
  • Regularly wipe surfaces that are covered with condensation.
  • If you have mould, use an anti-fungicidal wash and wear rubber gloves.
  • Don’t remove mould with a brush or vacuum cleaner - this spreads the spores.
  • And finally, heat your home to a constant moderate temperature of 16 to 18 degrees C, rather than short blasts in the morning and evening.


Condensation is not the only cause of damp

‘Penetrating damp’ is caused by moisture coming into the house through leaking or cracked pipework, a damaged roof, blocked guttering, gaps around window frames and cracked or defective rendering and brickwork. All these problems can be remedied.

‘Rising damp’ is due to a defective (or non-existent) damp course. This will leave a ‘tide mark’ about a metre above the floor. Fixing rising damp is a job for a qualified builder.

NB: Newly built homes can sometimes feel damp because the water used during its construction is still drying out.