How to Remove Mould on the Wall Safely

Mould on the wall develops when spores find moisture, limited ventilation and a suitable surface on which to grow. Removing the visible mark can improve the room, but the result will only be temporary if the damp ingress, leak or condensation feeding the fungus remains unresolved.

What should you check before starting to clean?

Start by assessing the scale of the issue and identifying the source of the moisture. Small patches on durable surfaces may be dealt with at home, whereas extensive areas, damaged walls or recurring mould may require professional repairs.

• Check roofs, pipework and windows for leaks;
• Look for signs of condensation in bathrooms and kitchens;
• Move furniture away to inspect the concealed wall area;
• Wear gloves, eye protection and a suitable mask;
• Open doors and windows before using any product;
• Keep children and pets away while cleaning.

How do you clean a small patch of mould from the wall?

Dampen the affected area before scrubbing so that spores are not dispersed around the room. On a washable surface, use water and detergent, scrub gently with a sponge or soft brush, then remove the residue with a clean cloth. Once finished, dry the wall thoroughly.

The method for removing mould marks can differ according to the paint and wall covering. Test any solution on an inconspicuous spot first, as harsh products may discolour paintwork or damage the finish.

Which mistakes should be avoided while cleaning?

The most frequent mistake is painting straight over the mark. Paint merely conceals the issue for a short time and may peel if moisture continues to pass through the wall. You should also avoid scraping or brushing the fungus while it is completely dry.

• Do not mix bleach with vinegar, ammonia or detergents;
• Do not use several products at the same time;
• Do not sand a mouldy wall without protective equipment and dust control;
• Do not put furniture back before the surface has dried;
• Do not use anti-mould paint to conceal damp ingress;
• Do not reuse contaminated cloths without washing them properly.

When can bleach be used?

Bleach is not needed for every cleaning task and may not penetrate porous materials effectively. For painted walls and durable surfaces, it is best to begin with water and detergent, physically removing the mould and drying the area. Plasterboard, wallpaper and other heavily contaminated materials may need replacing.

If a chlorine-based product is used, follow the dilution instructions on the label precisely, keep the room ventilated and wear protective equipment. Never mix bleach with another cleaning product, as the combination can release dangerous gases.

How can you stop mould from returning?

The most important measure is moisture control. Fix damp ingress, use extraction in bathrooms and kitchens, open windows each day, and leave a gap between furniture and cold walls. Wet surfaces should be dried promptly so the fungus cannot find the conditions it needs to grow again.

If the mark returns shortly afterwards, there is a strong damp smell, or the affected area approaches one square metre, seek specialist help. Only after the cause has been removed, the surface cleaned and it has dried fully is it advisable to apply a sealer and repaint.