The Most Common Causes of Damp

The Most Common Causes of Damp

By Ruth MacEachern

Product Manager

According to the UK government, damp is a major problem for households in the country, with between 4% and 27% of all homes suffering with some presence of dampness. The presence of damp can be a big issue for people with weaker immune systems such as the elderly, as damp patches are the ideal environment for mould to grow which can seriously affect health.

If you have discovered damp or mould in your home, it is important to deal with it as quickly as possible to stop the problem from getting worse and putting your health at risk.

What are the causes of damp

Damp patches are caused when moisture soaks into porous materials such as plaster. It can be hard to see damp initially, but as the problem worsens, it becomes more obvious. Peeling wallpaper or blistering paint on walls may indicate that the underlying material is saturated. Similarly, brown stains on walls could indicate that moisture is passing through the plaster and drawing pigment into the paint. Whatever the cause of damp, the symptoms will be the same, and once established, mould and mildew will start to grow.

There are three main types of damp, and while the treatment of them – redecorating and repairing walls – is the same, the causes are very different.

What is penetrating damp?

If you have spotted a damp problem on your ceiling, or high up on the wall, it may be penetrating damp. As the name suggests, penetrating damp is caused by water getting into the envelope of your home. The cause of penetrating damp is usually obvious as the damp patches will form close by. A leaking roof, a dripping pipe, or a gap in a window frame may be allowing water to get through and soak into the walls.

Removing the source of the water, whether by replacing a window frame, fixing the dripping pipe, or repairing a hole in the roof will stop the ingress of water, and once dried, the damage to your plasterwork can be repaired and repainted.

What is rising damp?

Rising damp is a major concern for homeowners and can significantly affect the sale of a property. Rising damp occurs when the damp proof membrane at the bottom of your walls is damaged and water can seep up from the ground. When rising damp is present, you will see stains on the bottom half of ground floor walls. Because the water is drawn up from the ground by capillary action in the walls, it will not form much more than a metre above ground level.

To prevent rising damp, a builder may need to replace the damp proof course in your walls and then replaster the interior walls. This can be a costly repair but will stop the problem long term.

What is condensation damp?

The third type of damp in UK homes is condensation damp. Condensation damp is caused by high humidity levels in your property because of poor ventilation. Water vapour from cooking, washing and drying clothes indoors saturates the air when it is warm, and is then released onto cold surfaces such as windows and walls. Without an obvious source, condensation damp can be hard to diagnose, but commonly occurs in rooms where there is a source of moisture such as a bathroom or kitchen, but thankfully it is one of the easiest types of damp to prevent.

Improving the ventilation in your home by fitting modern extractor fans in your bathroom and kitchen to reduce humidity will stop condensation almost immediately. In homes where condensation is forming away from an obvious source, whole house ventilation may be more appropriate. Positive Input Ventilation Systems (PIV) feature a central unit mounted in the loft which draws air into your home from outdoors and uses this to displace the stale or humid air keeping your home fresh and free from condensation.

Learn more

The longer you wait to deal with damp, the worse the problem will be. If you have found damp in your home and are worried about the risk to your health and property, our local ventilation specialists can help. Enter your postcode below to find an expert in your area who can visit your home to conduct a free survey and provide you with advice about the best solution for your needs.