Dampness and mould

Condensation is when moisture is absorbed into the warm atmosphere of a property and then, as the property cools down, the moisture condenses on cold surfaces such as windows or window sills.

It’s one of the most common forms of dampness found in buildings and can lead to a range of problem, such as peeling wallpapers through to unhealthy living conditions and black mould growth issues.

Problems with condensation are rising because our homes are better insulated, with double glazing and draught proofing, making them more airtight. The damp, moist air then stays within the building.

This is more likely to happen during the colder months – usually from September to May as homes aren’t ventilated so well because windows, doors and trickle vents are closed. This allows the build-up of water vapour in the house, which, in some cases, is enough to cause condensation.

The build-up of moisture from our day-to-day life comes from things like boiling the kettle, drying clothes inside, taking a shower and even breathing.

Where there is a suspended floor, condensation can also lead to dry or wet rot developing in floor timbers.

Signs of condensation

• The most common sign of condensation is water collecting on the inside of windows, on the windowsill or on tiles. Black mould may begin to grow on walls, surfaces, carpets, clothes, and fabrics such as bedding and curtains. This is usually seen as ‘black spot’ mould, but green, yellow, and white moulds can also develop.
• There are proven health hazards associated with moulds, the most common being that it’s a trigger factor for asthma. However, in most healthy people, only heavy, persistent moulds are likely to cause a problem, although some people may be particularly sensitive.
• You may also find you have a damp, musty smell in your house, or peeling paint or plaster.

Did you know that an average family of four will produce 2 to 3 litres of water per day?

Penetrating damp is where water finds its way into the property from the outside. Penetrating damp is mainly down to poor maintenance of the building. This can be from leaking gutters, broken pipes or poor brickwork. If there are any gaps in doors or windows, this can also lead to problems.

Signs of Penetrating Damp

• Damp patches on your walls which will appear bigger following heavy periods of rain. These damp patches can be found either inside or outside the building.
• Black mould appearing on the inner walls of the property can also be a sign of penetrating damp.

Rising damp is caused by ground water moving up through a floor or walls. Floors and walls will naturally soak up water from the ground, but usually it is stopped from causing damage by a barrier called a damp-proof course.

Newer properties will have a damp-proof course, but older buildings may not, or it may have been damaged. Bricks may appear solid enough, however, upon closer inspection bricks are full of voids. This is where a chemical damp proof course helps stops the moisture rising.

This type of dampness is mainly a problem in older properties where the damp proof course has become damaged, or was never put in/installed.

Signs of Rising Damp

• Having tide marks on walls is one of the most common ways of identifying rising damp. These tide marks will not appear higher than one metre from the ground. It is possible that there will also be yellow or brown damp patches and stains on the walls.
• Just like condensation, wallpaper will start to peel off the walls but the difference is that it will only occur on the lower parts of the wall.
• If rising damp comes into contact with timber, then you could see timber decaying as an outcome.
• Unlike condensation, white salts/crystals will be present on walls.