To stop damp from coming through your walls, you must first identify the root cause. Start by clearing any blocked air vents, installing a dehumidifier to reduce indoor humidity, and checking your external gutters for leaks. If the damp is rising from the ground, you can inject a damp-proofing cream or insert treatment rods into the lowest mortar course.
The best way to do this is by installing damp proofing which can come in the form of a cream and rods that are inserted into your masonry, or paint and a fabric membrane that can be installed onto your wall. These form a barrier to stop rising damp and condensation from soaking your walls and causing further issues.
Damp is often worse in a cold home, and heating can help reduce dampness problems, but it is a short-term fix, and you will always need to deal with the underlying cause to prevent damp. Using your heating to keep a property warm is essential and can help to slow down the spread of damp.
Penetrating damp is caused by moisture entering from outside. It often appears as damp patches on external-facing walls. Penetrating damp won't go away until the external issue is addressed – dehumidifiers help manage moisture but cannot fix the structural cause.
Installing waterproof tiles or a damp-proof course to stop moisture from penetrating the walls are two treatments for dampness in walls.
Opening your windows does temporarily purge humid air, but it cannot override the structural causes of persistent damp in your property. That brief surge of airflow feels reassuring: Persistent window condensation may clear from the panes, and the space smells fresher.
Condensation, leading to mould growth
This is by far the most common cause of damp and mould within properties, particularly during the winter months. As the weather gets colder and heating is turned on, windows are generally fully closed.
Direct warm air at small damp patches to lift off surface moisture and condensation. Run a dehumidifier to remove excess moisture and address the issue of moist air. Improve ventilation by opening windows so that you have plenty of fresh air.
Summer: Peak Mold Growth Season
Summer is by far the worst time of year for mold growth. Warm air holds more moisture, and when combined with poor ventilation, it creates an ideal environment for mold colonies to thrive indoors.
As temperatures drop, homes are more at risk of condensation, damp and mould. Cold air holds less moisture, and when warm, moist air inside your home hits cold surfaces like windows and walls, condensation forms.
Research has shown that English Ivy can eliminate up to 78% of airborne mold within 12 hours. This makes it particularly useful in humid areas like bathrooms and basements where mold growth is more common.
Noticeable signs of damp include the following:
Kill Mold: Spray the mold with a liquid biocide to kill it. Alternatively, exposing the mold to air and light for long enough will kill it.
Each person sleeping in a bedroom will contribute about 200ml of water into the air overnight. This constant addition of moisture means that the air in the room is constantly shedding water onto windows and walls and adding to your condensation problem.
How to treat rising damp myself?
It is important to know what is causing the problem as using a dehumidifier to solve damp caused by a structural defect will only make the situation worse.
Understanding the difference between wall dampness and water leakage from walls protects your home from water damage. Wall dampness develops gradually from humidity and poor ventilation, while water leakage from walls involves active water intrusion requiring immediate attention.
Ignoring water damage promotes mold growth, leading to respiratory issues and allergic reactions. Prolonged moisture weakens structural elements, risking foundation instability and safety hazards. Unaddressed leaks increase energy consumption, resulting in higher utility bills.
Warm air holds more moisture than cool air – the warmer it is, the more it can hold, meaning less condensation. It's better to keep a medium temperature throughout your home than to heat one room to a high temperature. If you can, improve your home's insulation and draught proofing to keep surfaces warmer.
Damp and mould within the home can produce allergens, irritants, mould spores and other toxins that are harmful to health. Even if visible mould is not present, dampness alone can increase the risk of health problems.
Rising damp, penetrating damp, traumatic damp and condensation are the four most common types of damp in residential homes.
Sleeping with your windows open is generally safe and can even promote better sleep by keeping the room cool and well-ventilated. However, experts advise against it if you live in a high-crime area, are prone to severe allergies, or if outdoor pollution and noise are high.
Optimal indoor humidity for health between 40% and 60% can help reduce the risk of respiratory infections, allergic reactions and skin irritation. High humidity above 60% can make the air difficult to breathe while low humidity can cause dry skin, itchy eyes and a sore throat.
Many Germans adhere religiously to the practice of Lüften ("ventilation"): At least twice each day, especially in the winter, they throw open all the windows to blast out stale air — as a matter of hygiene and good health. (Some people in the Low Countries and Scandinavia have a similar custom.)