The three most common kinds of damp are rising damp, penetrating damp and condensation. To work out the best way to treat the damp in your home, you’ll need to work out which of these you have (Rising damp, damp penetration or condensation). Below is a guide to understand the cause of the increased moisture levels.

Rising damp is caused by ground water moving up through a wall. This is usually prevented from causing damage by a barrier called a damp-proof course. This can be seen as a horizontal plastic black strip at low level on the outside wall (typically visible on properties built from 1960 onwards). Older properties (without the black strip) have a damp proof course but are prone to a breakdown over time

If you have rising damp you may notice damaged skirting boards and floorboards, crumbling or salt stained plaster and peeling paint and wallpaper. There may also be a tide mark along the wall at low level.

Penetrating damp is caused by water leaking through walls and/or ceilings. This type of damp can be seen in various areas of a property in most cases at high level. Penetrating damp is usually caused by structural problems in a building, such as faulty guttering or roofing. Or can be the result of leaking pipework

Penetrating damp often shows up through damp patches on walls, ceilings or floors, which may darken when it rains or when taps are run.

Condensation is the most common kind of damp and is caused by moist air condensing on walls. It’s mainly a winter problem, as at this time of year walls are much colder than the air inside. Condensation can be made worse by poor ventilation, and heating that comes on and off, as this allows warm, damp air to condense.

You may notice water droplets on windows or walls, see dark mould appearing and/or notice an unpleasant smell.

It is important to look throughout your home for signs of the first two types of damp as they could increase the levels of condensation. If you can clearly confirm that the first two are not visible then you should take the following steps:

  • Ensure walls and windows are dry and free from moisture
  • Ensure rooms are adequately ventilated to allow moist air to be removed from the property
  • Ensure the property is heated adequately to allow rooms to remain warm especially during colder periods
  • Wash mould of walls, ceilings and windows to prevent the mould growing. It is advised that an anti-bacterial spray is used to reduce re-growth.