Black mould on walls, ceilings and window reveals is one of the most common problems we are asked about. Cleaning it off helps, but unless the moisture causing it is dealt with, it will almost always return.
Why mould keeps coming back
Mould needs moisture. In most homes that moisture comes from condensation: warm, moist air from cooking, showering, drying clothes and breathing meets a cold surface and turns back into water. External wall corners, behind furniture and around windows are the coldest spots, which is why mould appears there first.
Bleach can lighten the staining on the surface, but it does not change the conditions that let mould grow, so new growth soon appears.
Cleaning mould safely
- Wear gloves and eye protection, and ventilate the room
- Use a mould-removal product made for the purpose and follow the instructions
- Wipe gently with a damp cloth rather than dry brushing, which can spread spores
- Bag and throw away cloths afterwards
- Large areas, mould on soft furnishings, or anyone in the home with breathing problems are good reasons to get professional advice
Stopping it coming back
Long-term control means reducing moisture and improving air movement:
- Use extractor fans when cooking and showering, and leave them running afterwards
- Keep trickle vents open and avoid drying washing on radiators
- Leave a gap between furniture and external walls
- Heat the home steadily rather than in short bursts
- Consider whole-house ventilation, such as positive input ventilation, where moisture levels stay high
When it isn’t condensation
Mould can also be a sign of penetrating damp, a plumbing leak or rising damp. If mould appears in one isolated area, at low level, or after heavy rain, it is worth having the cause properly investigated.
Our surveyors take humidity and surface temperature readings to find out why mould is forming, then recommend solutions that last. See our condensation and mould control service.
