Damp and condensation

Damp can cause structural damage to a building.  It can lead to tide marks and mould on walls and furniture, and make wooden window frames rot.

In most cases, the cause is condensation and not damp. 

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 'tide mark'. It tends to appear 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 or damp?

Condensation is not the only cause of damp areas within a home. 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 'tide mark'.

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.

Dealing with condensation

Many of the causes of condensation, mildew and mould are to do with the way we live our lives in our homes. You can solve many of the problems by following these simple steps.

  • Produce less moisture

    Some ordinary daily activities produce a lot of moisture very quickly:

    • When you’re cooking, put lids on saucepans and ensure windows are open or extractor fans are on
    • Dry clothes outside, If you need to dry your clothes indoors, ensure the door is closed and windows are open
    • If you use a tumble dryer, make sure it is vented to the outside. If you have a condensing dryer, ensure any windows in the room are open
    • Put a small amount of cold water in the bath before you turn on the hot tap
    • Do not run your shower for longer than needed
    • Mop up any condensation or water everyday- this includes on window ledges and cills
    • Shut kitchen and bathroom doors when bathing and cooking to stop water vapour from spreading around your home.
  • Treat mould and mildew

    Treating mould or mildew that appears on surfaces in your home is straightforward. There are numerous cleaning products available in supermarkets. Once purchased, follow the instructions provided to treat the affected area and monitor for regrowth.

  • Questions?

    If you can say ‘yes’ to all the following questions you’ll be helping yourself to reduce condensation and avoiding damp and mould in your home

    • Do you cover saucepans with a lid when cooking?
    • Do you open a window in your kitchen to allow water vapour to escape when you're cooking?
    • Do you dry your washing outside in the fresh air when you can?
    • Is your extractor fan working and switched on?
    • If you use a tumble dryer, is it properly vented to the outside, or is the window open in the room it is in?
    • Is your bedroom well ventilated at night? (a window left slightly open or the door to your room left ajar and air vents left open?)
    • Can air circulate freely between your furniture and the walls?
    • Do you keep your heating on low all day when it is cold?
    • Are the airbricks open and not blocked by furniture or other items?
  • Things not to do

    Do not:

    • block permanent ventilators
    • completely block chimneys. Instead, leave a hole about two bricks in size and fit a louvered grille over it
    • draught-proof a room where there is a cooker or a fuel burning heater, for example, a gas fire
    • draught-proof windows in the bathroom and kitchen.
  • If things don’t change

    If you’ve followed our advice and made some changes to things you do in your home and are still having problems with condensation, damp or mould, please call our Customer Services Centre on 0300 373 3000.