Quick answer: anti-mould paint only works on a clean, dry, mould-free surface. Kill and remove the existing mould, let the wall dry completely, scrape off loose paint, sand and seal any patched areas, then apply two coats of anti-mould paint, leaving the drying time stated on the tin between coats. Anti-mould paint resists new mould on the paint surface, but it cannot stop mould if the wall stays damp, so fix leaks and ventilation too.
What anti-mould paint does (and does not do)
- It does: contain additives that resist mould and mildew growing on the paint film, which helps in humid rooms such as toilets, kitchens and store rooms.
- It does not: kill mould that is already there, stop water coming through a wall, or fix a leak from the flat above.
That is why preparation matters more than the paint. Painting anti-mould paint over live mould traps it underneath, and it comes back through the new paint.
What you need
- Gloves, safety glasses and a mask (scraping mould releases spores)
- A mould remover or diluted bleach solution, a sponge and a spray bottle
- A scraper and sandpaper
- Filler for cracks and holes
- Sealer or primer for bare and patched areas
- Anti-mould paint, a roller, a brush and a tray
- Drop sheets and masking tape
Never mix bleach with ammonia or other cleaners: the fumes are dangerous. Our mould removal guide compares bleach, vinegar and mould removers on painted walls.
Step by step
1. Find and fix the moisture
Check for leaks from pipes, windows or the flat above, and make sure the room can be ventilated. If a toilet ceiling has brown rings or stays damp, read steam or a leak? before painting.
2. Kill the mould
Apply the mould remover to the affected area and a little beyond it, leave it for the time stated on the product, then wipe clean. Repeat on stubborn spots.
3. Let the wall dry completely
Open windows and run a fan. In Singapore’s humidity, this can take a day or more. Painting on a damp wall is the most common reason anti-mould paint fails.
4. Scrape and sand
Remove all loose, flaking and bubbling paint until the edges are firm, then sand them smooth so the repair does not show.
5. Fill and seal
Fill cracks and holes, sand them flat, then apply sealer on the bare and patched areas so the paint bonds evenly. See what sealer paint is for.
6. Apply two coats of anti-mould paint
Stir the paint well. Cut in the edges and corners with a brush, then roll the open areas. Leave the recoat time stated on the tin before the second coat. One thin coat does not give full protection.
7. Ventilate and keep it dry
Keep windows open while the paint dries and for a few days after. From then on, run the exhaust fan during and after showers.
Common mistakes
- Painting straight over mould without killing it.
- Painting on a wall that is still damp.
- Applying only one coat.
- Using anti-mould paint on a wall with an unfixed leak.
- Skipping sealer on patched or bare plaster, so the paint peels.
Where to use anti-mould paint in Singapore homes
- Toilet and bathroom ceilings and walls
- Kitchen walls and ceilings
- Bedroom ceilings, especially rooms with air-conditioning and little daylight
- Walls behind wardrobes and in store rooms
- Walls facing the outside that get damp in the rainy season
For which products suit which rooms, see our anti-mould paint guide.
DIY or professional?
A small patch of mould on a bedroom wall is a reasonable DIY job. Call a professional if the mould keeps coming back, covers a large area or a whole ceiling, or if you see water stains that suggest a leak. Our anti-mould ceiling upgrade is +$40 per bedroom on top of a painting package, and major peeling and putty repair is $40 to $290, depending on the damage (see our price list).
Frequently asked questions
Can I paint anti-mould paint directly over mould?
No. Kill and remove the mould first, and let the wall dry. Otherwise the mould grows back through the new paint.
How many coats of anti-mould paint do I need?
Two, over a sealer on any bare or patched areas. Follow the recoat time on the tin.
How long does anti-mould paint last?
It depends on how damp the room stays. In a ventilated room with no leaks it protects for years, but in a room that stays wet, mould can return on any paint.
Is anti-mould paint safe for bedrooms?
Water-based anti-mould paints are commonly used in bedrooms. Keep the room ventilated while it dries, as with any paint (see how long paint smell lasts).
Mould keeps coming back?
WhatsApp us a photo of the wall or ceiling and we’ll tell you what it needs and what it costs.