Common situation
Mould behind a wardrobe or in a bedroom corner: what to check first
Dark spots behind a wardrobe or in a bedroom corner are often mould on a surface that stays cold and damp, but appearance alone can't confirm it or tell you whether water is getting in. Find out why that spot stays wet before you clean it or buy a machine.
What it usually points to
Black spots that come with damp or a musty smell are often mould, but appearance alone can't confirm it, and this page can't tell what they are. Without a humidity reading we can't tell how damp the whole home is.
What to check and try first
- If the patch is smaller than a dinner plate and on a hard surface like tiles or glass, clean it with detergent and water, wearing rubber gloves, eye protection and a P2 mask, with the room ventilated. Then dry the surface fully. If it's bigger, on plasterboard, carpet or fabric, or you're not sure, don't scrub it: report it or get it looked at.
- If the outdoor air is clean, open the windows wide for a few minutes each morning, then close them. Cold outdoor air often holds little moisture, so this can help; skip it during smoke or poor outdoor air.
These steps assume only: black spots, possibly mould, on a ceiling, wall or window frame; the problem spot is on an outside wall, corner or behind furniture. Your home may be different. Add what else is going on and you'll get steps for your situation.
Check my home with these answers
What would change this
If damp keeps coming back in the same place, water is getting in, or mould grows past a dinner plate or onto a second wall, the cause needs investigating, not a machine. If it still feels heavy after two weeks of these steps, measure the humidity.