Where Does Damp Come From

The presence of damp in your home can be worrying. Aside from being unsightly, damp can do considerable damage to the fabric of the building that is expensive to repair. Beyond this, damp can also lead to the growth of mould and mildew which, over time, can be harmful to the health of anyone in the property – particularly older people, young children, and those with respiratory conditions such as asthma. It is important to deal with damp quickly to prevent it from causing too many problems, but it is equally important to find and remove the source so that the issue does not simply recur.

The different types of damp

While all kinds of damp are the same – a build up of moisture below the surface of walls or in wood, the cause of that damp can differ and is dependent on the source of that moisture. There are three main types of damp that are commonly found in the home, and each of them needs to be dealt with in a specific way to prevent it from coming back.

Rising Damp

The most worrying type of damp that you might have in your home is rising damp. Thankfully, in modern properties, it is relatively rare, but it can be expensive to deal with and requires a building specialist.

Rising damp is caused by water from the ground being drawn up into walls via capillary action. In modern buildings, a damp proof course is installed in walls just above the ground – this is a plastic membrane which stops ground water from rising above floor level, but in homes without protection, rising damp can develop over time.

Rising damp only affects the ground floor of a building and is quite easy to recognise. You will notice a stain on the walls that spreads up to about one metre above floor level. This is the limit that water can soak into the walls from below. In areas with rising damp, plaster will start to crumble, and paintwork will start to flake off. Door frames may begin to rot. Rising damp needs to be addressed by a builder who can install a damp proof layer in the wall to stop the problem and then repair the damage.

Penetrating Damp

Whereas rising damp comes into the house from below, penetrating damp comes into the house through the roof and walls, or from pipes.

Penetrating damp causes the same problems with plaster and woodwork in the property, but you will often find it in the corner of ceilings, or on walls around windows. Usually, penetrating damp can be recognised due to a brown stain around the area which is formed by the material picked up by the water as it soaks through.

Penetrating damp can be easier to resolve than rising damp. There is usually a sole source that needs to be repaired, and if the problem is found and quickly fixed the amount of damage will be minimised.

Condensation Damp

Condensation damp is caused when the water held in humid air condenses on surfaces such as walls and ceilings and then soaks below the surface. Many activities in our homes including cooking, bathing, and drying clothes contribute extra water vapour into the air, and this becomes condensation when it meets cold surfaces.

To prevent condensation damp, you need to take steps to reduce the humidity level in your home. IN most cases this will mean improving the ventilation so that moist air can be expelled from the building before it has a chance to form condensation.

Improved extractor fans in bathrooms and kitchens will remove a lot of the moisture at source, but as around 60% of water vapour in the air comes from the breathing of occupants, extractor fans will only deal with part of the problem, and you may want to invest in a more effective whole house ventilation solution such as Positive Input Ventilation (PIV) which works by drawing fresh filtered air into the building from outside to displace the moisture laden air.

Condensation Damp can be a major problem in homes, particularly during the winter when the outside air is cold and the air can hold less moisture, and it is important to deal with condensation before it starts to damage your property or becomes a breeding ground for mould.

Find out more

Our ventilation specialists across the UK can help you stop condensation and prevent damp for good. Enter your postcode below to find a local expert who can visit your home to conduct a free survey that will identify the cause of condensation and offer you advice about the best way to stop it from developing into a more expensive damp problem.