Mould: Recognising, Preventing and Removing It to Protect Your Health

Mould is not always easy to smell or see, often hiding under floor coverings, behind wallpaper or furniture. The fact that mould is a health hazard is often underestimated.

How dangerous is mould?

Airborne mould spores mainly cause allergies. However, they can pose various health risks. In general, the higher the mould concentration and the longer the exposure, the greater the potential health damage. A person’s physical condition and the type of mould also play a crucial role.

Why is mould in your home so dangerous?

We spend most of our time indoors. When mould grows inside a home, it becomes a serious health threat. Mould spores spread invisibly through the air. When inhaled, they can cause severe allergic reactions. It is still unclear how high the mould concentration must be to trigger symptoms and make people sick.

Because mould growth often goes unnoticed, it is essential to look out for the following warning signs in yourself or your family members:

• Allergic reactions
• Respiratory issues such as asthma or bronchitis
• Hoarseness, coughing, sore throat
• Nausea, stomach pain, digestive problems
• Headaches
• Fatigue, insomnia, exhaustion
• Red, burning eyes
• Rashes, redness, eczema
• Infections
• Lung and heart conditions

How does mould form indoors?

Mould develops wherever excess moisture is present. Common causes include:

• Cracks or leaks in walls, roofs or windows
• Poor insulation
• Improper ventilation and heating
• Condensation on cold walls

Older buildings are particularly vulnerable due to inadequate thermal insulation. Mould can also develop in new buildings or after renovations if the rooms are not properly dried.

Even in homes without structural issues, indoor air humidity builds up daily — up to ten litres in households with multiple people, through showering, cooking, and drying laundry. Warm air holds moisture, which condenses on cold surfaces and creates damp spots — ideal for mould growth.

Preventing mould

Mould can be effectively prevented with these simple tips:

• Heat all rooms evenly to avoid large temperature differences
• Vent moisture (e.g., after showering or cooking) directly to the outside
• Ventilate regularly to ensure proper air circulation
• Open windows wide (shock ventilation); cross-ventilate by opening windows on opposite sides
• Heat even unused rooms adequately

By following these tips, mould has little chance to spread.

What to do if you find mould?

In a rental property, the landlord is responsible for removing mould and protecting tenants’ health. Landlords often blame tenants for poor ventilation or heating. However, they must prove that the building structure is not the cause — such as poor insulation.

If you own the property, you are responsible for mould removal. If the mould patch is larger than a credit card and the surrounding wall is damp, you should hire a professional company to handle the removal. Only this can ensure your family’s health and safety.