If you own or rent an older home, damp is likely to be a problem at some point. This is due to a combination of factors including construction methods, lack of ventilation due to new double glazing, lack of modern waterproofing materials, and general wear and tear over time. And, as always, it is easier to avoid damp and the problems it comes with rather than trying to fight a battle with mold and damp patches.
Understanding the Types of Damp
Before you prevent or treat damp, you need to know what you are dealing with. There are three main types of damp: rising damp, penetrating damp, and condensation.
Rising damp - when groundwater seeps up through the walls due to a compromised or non-existent damp-proof course (DPC). If you have rising damp, it will need to be treated to prevent longer term problems. Damp-proof course injections, improved drainage, and internal damp-proof membrane are all possible options and although expensive, will prevent structural damage and make your property easier to rent or sell in the future.
Penetrating damp - when water enters the building through external defects like damaged roofs, gutters, or walls.
The exterior of an older home is often more vulnerable to damp due to weathering and deterioration over time. Regular maintenance can prevent water ingress and the resulting damp issues.
- Check the roof for missing or damaged tiles and ensure the flashing is intact around chimneys and roof junctions.
- Clear gutters and downpipes regularly to prevent blockages, which can lead to water overflowing and penetrating walls.
- Inspect walls for cracks or damaged render and repair promptly. Consider applying a breathable, water-repellent coating to brickwork to prevent water absorption while allowing trapped moisture to escape.
Condensation - when moist air meets cooler surfaces, leading to mold and mildew growth.
Poor ventilation is a common cause of condensation, especially in older homes. Various methods can reduce the problem. Try:
- Installing or upgrading extractor fans in high-moisture areas like kitchens and bathrooms.
- Regularly opening windows to allow fresh air circulation.
- Using trickle vents on windows to provide continuous ventilation without fully opening them.
While good ventilation can help to prevent damp, controlling condensation by reducing indoor humidity and preventing warm air from contacting cold surfaces is important too. Practical steps include:
- Using lids on pans while cooking and ensuring extractor fans are on.
- Keeping bathroom doors closed during and after showers to contain moisture.
- Insulating cold surfaces, such as external walls, to prevent them from cooling to a temperature where condensation occurs. Adding insulation or plasterboard with an insulating layer can be effective.
If you live in a rented property and you notice damp, contact your agent or landlord to inspect and treat the problem. If you own your property or are looking to buy a property with damp problems, contact a damp specialist for advice on how to proceed. For more tips, follow us on Facebook or X.