Damp and mould

There are three common types of damp; these are rising damp, penetrating damp and condensation. Too much moisture causes damp and mould. Read below for further information on what causes it, preventative measures that you can take and what to do if you have a problem with damp and mould.

Rising damp

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

Rising damp on a wall

Penetrating damp

Penetrating damp happens when water seeps into a building through walls, roofs or below ground areas. This can happen when:

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

Penetrating damp on a wall


Condensation occurs when warm humid air (e.g. from cooking, showering or drying washing) hits a cold surface such as windows and external walls. Condensation is common in areas of the dwelling where there is little movement of air, e.g.

  • near or on windows
  • cold wall surfaces
  • in or behind furniture and wardrobes
  • in corners
  • on north facing walls

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

Damp and mould can also contribute to a person experiencing poor mental health due to their living conditions.

Black mould on windows

How to prevent condensation and mould

  • Reduce moisture by wiping any damp or wet surfaces
  • Heating - maintain a low-level consistent temperature and avoid temperature fluctuations
  • Ventilate - keep a window slightly open to allow moist air out and keep trickle vents open if you have them
  • Keep doors to kitchen or bathroom closed after having a shower/bath or during cooking and use the extractor fan if there is one
  • Remove mould as soon as you see it by cleaning the area with a fungicidal wash/spray (follow any instructions carefully)
  • Dry the area thoroughly.

If you're having issues with mould and damp in your property:

  • Contact your landlord to report the issue
  • Do this in writing so there is a clear timeline of when the issue was reported
  • Describe the problem/s and ask your landlord to investigate and do the necessary repairs or improvements
  • Do not stop paying your rent. This can put you at risk of being served an eviction notice
  • If your landlord does not investigate the problem within a reasonable amount of time, download and complete our housing service request form; you can either print and post or email it to us at [email protected]. Please also include a photo of each entire room in your property and also of the damp issue.

Further advice and guidance resources