Clean it off safely, then find out why it grew there. Cleaning removes the mould, not the reason it came.
Black mould on a ceiling means that part of the ceiling is staying damp. In most homes that is condensation: warm, moist air from the room settling on a ceiling that is colder than the rest. It is usually worst where the ceiling meets an outside wall, in bathrooms and kitchens, and in bedrooms, where people breathe out moisture all night.
Less often the water is coming from above: a roof leak, a blocked gutter overflowing into the wall head, a leaking pipe, or a bathroom extractor fan venting into the loft instead of outside. The shape and position of the mould usually tell you which.
Open a window and keep the door shut to the rest of the house while you work.
Rubber gloves, eye protection and a mask. If anyone in the home has a breathing condition or is pregnant, it is better someone else does it.
Use a mould remover and follow the label. Wipe gently with a damp cloth, never brush it dry, then bin the cloth.
Take a photo. If it is back within weeks, in the same shape, the cause is still there.
Do not paint over it yet. Can I just clean it or paint over it? explains why.
Mould in a band where the ceiling meets the outside wall, often worst in the corners, is a classic cold spot. Very often the loft insulation stops short at the eaves, or has been pushed back.
Darker lines at regular spacing can follow the joists or gaps in the insulation above. The cold parts of the ceiling collect moisture and dirt first.
Mould inside or around a brown stain usually means water from above: the roof, a pipe, a tank or a bathroom. See damp patch on the ceiling.
Fine black spots over most of a ceiling, especially in a bathroom or bedroom, point to a room that is too humid for too long. Ventilation is the first place to look.
Only go into the loft if you can do so safely, stepping on joists or boards and never on the ceiling between them.
Bedrooms are where we see ceiling mould most often. A night's breathing adds moisture to a closed room, the heating is often off or low, and the outside wall and the ceiling next to it are the coldest surfaces. If the mould is in the bedroom, read is it safe to sleep in a room with mould?
Vigilant Surveys is an independent damp and mould surveying practice covering East Anglia, North London and the West Midlands. We carry out no remedial work, sell no products and take no commission from anyone who does the repairs, so there is nothing to sell you afterwards.
Every survey includes thermal imaging, moisture readings against a dry control and hygrometer readings, and you get a clear written report within 24 hours of the visit. £350 for the problem areas, £450 for the whole property, fixed prices, no payment to book.
Usually condensation. Breathing overnight puts moisture into a closed bedroom, and it settles on the coldest surface, which is often the ceiling where it meets an outside wall. Missing or pushed back loft insulation at the eaves makes that spot colder still.
Government health guidance says damp and mould can affect anyone's health, particularly breathing, and that some people, including children, older people and people with health conditions, are more at risk. Clean it off safely, deal with the cause, and if you are worried about your health speak to your GP.
Because the ceiling is still staying damp. Cleaning removes the mould you can see, but unless the moisture is reduced or the cold spot is dealt with, it grows back, usually in the same shape.
Not until the cause is found and fixed and the ceiling is dry. Paint, even mould resistant paint, hides it for a while but does not stop a cold or wet ceiling growing mould again.
If you can see an obvious leak, call the trade that fixes it. If you cannot tell why the mould is there, an independent damp and mould surveyor finds the cause first, so you only pay for the right repair.
No payment to book. Tell me what you are seeing and I will call you straight back, usually within a couple of hours, to arrange a visit and confirm the fixed price.
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