How to remove black mould from walls and window seals safely
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Black spots on window seals, bathroom silicone or the corner of a bedroom ceiling are mould. Small patches caused by condensation are something you can clean yourself. Here is how to do it safely, and how to stop it returning.
Before you start
- Wear rubber gloves, goggles and a mask (an FFP2 or FFP3 dust mask is best).
- Open the window and close the door to the rest of the house.
- Do not brush or vacuum dry mould: that releases spores into the air.
- People with asthma, allergies or weak immune systems, and pregnant women, should ideally get someone else to do it.
What to use on each surface
| Surface | Use |
|---|---|
| uPVC frames, tiles, glass | A bleach-based mould and mildew spray, or a non-bleach mould remover |
| Silicone sealant | Mould gel left on for several hours; if stains remain, the silicone needs replacing |
| Painted walls and ceilings | A non-bleach mould remover (bleach can discolour paint), then an anti-mould paint once dry |
| Fabrics and curtains | Wash at 60°C if the label allows; otherwise professional cleaning |
Where to buy (prices change often, so check the current price):
Never mix cleaners
Never mix bleach with vinegar, ammonia or other cleaners. Some combinations release toxic gases. Use one product, rinse, and only then try another.
Step by step
- Spray the product on the mould and leave it for the time on the label.
- Wipe with a damp disposable cloth, folding it so you always use a clean side.
- Repeat if needed.
- Dry the surface thoroughly with another cloth.
- Put the cloths in a sealed bag and bin them.
Stop it coming back
Mould grows where surfaces stay damp. Keep indoor humidity around 50% (see what humidity your home should be), stop condensation on windows, and consider a dehumidifier for the worst room.
If you rent
Report damp and mould to your landlord or housing association in writing, with photos and dates. In England, new rules (often called Awaab's Law) are bringing in strict deadlines for social landlords to deal with damp and mould hazards, and private landlords also have duties to keep homes free of serious hazards.