How to deal with mould on walls safely

Mould is often a sign that moisture is staying in a room or on a surface. A careful first response can limit spread while the source is investigated.

Professional Safety Note

Start with the room, not just the mark

Take a few photos and note where the mould appears, whether the wall feels damp, and whether there has been a leak, condensation, or a long period with the property closed.

Keep children, guests, and anyone sensitive to mould away from the affected area. If practical, close the room off while you decide on the next step.

1. Avoid moving soft furnishings through other rooms until they have been checked.
2. Ventilate only when outdoor conditions will not add humidity; do not use a fan that blows directly across visible mould.
3. Check for obvious signs around windows, wardrobes, bathrooms, and plumbing without opening walls or dismantling fittings.

Clean only a small, stable surface

For a small surface spot on a washable, sound finish, follow the product label and the material manufacturer’s guidance. Use gloves, protect nearby items, and never combine bleach, acids, ammonia, or other products.

Do not paint over a damp or mouldy wall. The moisture source needs attention first, or the mark is likely to return.

When property support helps

A local property support visit can document visible signs, coordinate an agreed cleaning scope, and help pass clear information to the owner or a specialist contractor. It is not a remote diagnosis or a substitute for building, plumbing, or health advice.