Types of damp and what causes it, how to prevent damp and mould, what to do if there's damp or mould in your home.

Types of damp and what causes it

Too much moisture causes damp and mould. There are 3 types of damp:

  • penetrating damp
  • rising damp
  • condensation

Penetrating damp

Penetrating damp happens when water seeps into a building.

This can happen when:

  • the roof or rendering is damaged
  • the gutters are blocked
  • pipes are leaking or plumbing is damaged
  • areas around sinks, showers or baths are damaged, such as cracked grouting or worn out sealant

pdf Examples of penetrating damp (337 KB) .

Rising damp

Rising damp happens when water rises from the ground through the floor andinto the walls of the building. You can often see rising damp because it leaves a tide mark low down on affected walls.

pdf Examples of rising damp (144 KB) .

If you think your home has penetrating or rising damp, tell your landlord as soon as possible. Damp can cause a lot of damage if you ignore it. 

Damp in new homes

If you live in a new or recently built property, it may not have dried out from water left from the building work. It can take between 9 and 18 months to dry completely. If you're worried, contact your landlord.

Condensation and mould

Condensation happens when warm humid air hits a cold surface, such as windows and external walls. Warm humid air is made by activities such as showering or cooking. 

Condensation is common in areas where there is little air movement, such as:

  • behind furniture
  • in cupboards
  • under work surfaces
  • on north facing walls
  • in corners

If a property doesn't have good ventilation and heating, condensation can cause mould and other fungi, certain species of house dust mites, bacteria or viruses. Mould is a type of fungus which grows in damp conditions. Its spores can cause or make some medical conditions worse, such as:

  • respiratory infections, such as bronchitis
  • allergies
  • asthma
  • eczema

Some people who are exposed to damp and mould might experience poor mental health as a result of their living conditions.

pdf Examples of mould and damp caused by condensation (453 KB) .

How to prevent condensation and mould growth 

Reduce moisture by wiping any damp or wet windows, sills, walls and surfaces with a paper towel and throwing it away.


  • Keep low, background heating on all day if possible and a window slightly open (warm air can hold more moisture so you're less likely to have condensation).
  • Don't put heating on for short periods of time (this will make the problem worse because the air heats and cools quickly).
  • Don't use liquid, propane gas or paraffin heaters because they produce a lot of water vapour.

See Cost of living support if you cannot afford to heat your home.

Help air move around

  • Leave doors open unless you're cooking, having a shower or bath, or drying clothes.
  • Keep furniture away from walls, particularly external walls, if possible.
  • Don't overfill cupboards and wardrobes.
  • Don't block airbricks or vents.
  • Don't completely block chimneys, leave a hole and fit an air vent.
  • Keep a window slightly open, if possible, because this will help moisture escape.
  • Keep trickle vents open if you have them. A trickle vent is a small slot above a window or door that allows air in and out when the door or window is closed.

It might seem strange to keep the heating on with a window slightly open, but it helps because you're letting air that's full of moisture out and dry air in. Dry air is easier and cheaper to heat.


  • Close the kitchen door.
  • Open a window or put the extractor fan on.
  • Cover pans with lids.
  • Don't leave pans or the kettle boiling longer than needed.

Having a shower or bath

  • Close the bathroom door.
  • Open a window or put the extractor fan on.
  • Leave the window open or fan on until all the moisture has gone from the windows and walls.
  • When you have a bath, put some cold water in the bath first and then add hot water. This will reduce the amount of steam produced.

Drying clothes

  • Dry clothes outdoors if possible.
  • If you have to dry clothes indoors:
    • put them in a room with the door shut and heating on
    • open a window (or put the extractor fan on if they're in the bathroom)
  • If you use a vented tumble dryer, make sure it has a hosepipe taking the moisture outside.


  • Remove any mould as soon as you see it.
  • Clean the area with soapy water or a fungicidal wash (follow any instructions carefully).
  • Don't brush or vacuum the area because it can disturb mould spores.
  • Dry the area thoroughly.
  • Paint the area with a fungicidal paint. Don't use ordinary paint or wallpaper.

If you are in private housing find out more about preventing damp and mould in our  pdf damp and mould leaflet for private or housing association tenants (375 KB) .

If you still have damp or mould in your home

Contact the provider of your home if you still have damp or mould and you:

  • have followed the advice on this page
  • cannot follow the advice on this page because of an issue with your home (for example, the heating doesn't work or the extractor fans are broken)

The provider of your home will be your landlord, lettings agent or the council.

They must investigate and fix the damp or mould if it's caused by disrepair, such as:

  • no working heating
  • broken extractor fan

If you're a council tenant

To report damp and mould, if you're a council tenant:

Council tenants can also contact the Centre for Sustainable Energy who can provide advice on heating or bills and give practical tips for keeping your home warm.

If you're not happy with the service received from us, you can make a complaint.

You must contact us to report the issue.

Do not stop paying your rent because there's damp or mould in your home. This could put you at risk of being served an eviction notice.

If you're a tenant of another provider or private landlord

You must contact your landlord or lettings agent to report the issue.

Clearly describe the problem and ask your landlord or agent to investigate and do the necessary repairs or improvements.

Do this in writing in case you need to prove that they knew about the problem at a later date.

Do not stop paying your rent because there's damp or mould in your home. This could put you at risk of being served an eviction notice.

If your landlord or lettings agent do not investigate or do the necessary repairs within a reasonable amount of time, fill in our problems in your property form for private or housing association tenants