How to Remove Mould from Walls in Singapore (and Stop It Coming Back)
For light mould on painted walls: ventilate, wear gloves and a mask, spray a mould remover or a diluted bleach solution, wait 10 to 15 minutes, wipe gently, rinse and dry completely. If the black spots come back within weeks, the problem is moisture, not cleaning. Fix the source, then repaint with an anti-fungal primer and anti-mould paint.
In this guide
Why walls get mouldy in Singapore
Singapore’s humidity often sits between 70% and 90%. Mould spores are always in the air and only need moisture and still air to grow. The usual hotspots:
- Bathroom ceilings and corners, especially without a window or exhaust fan
- Behind wardrobes and beds pushed against external walls
- Household shelters and storerooms that stay closed
- Around aircon units and trunking that drip
- Below leaking pipes, windows or the flat above
What you need
- Rubber gloves, a mask and eye protection
- A mould remover spray, or household bleach diluted with water
- A soft sponge or microfibre cloth (avoid harsh scrubbing on matt paint)
- A spray bottle of clean water and a dry towel
- A fan or dehumidifier to dry the wall
Safety: never mix bleach with ammonia or other cleaners. It releases toxic gas. Keep windows open, and keep children and pets out of the room.
How to remove mould from walls: step by step
- Open windows and switch on a fan so fumes and spores clear.
- Test a small hidden spot first. Some removers can lighten coloured paint.
- Spray the mould and leave it for the time on the label, usually 10 to 15 minutes.
- Wipe gently with a soft cloth. Don’t scrub hard or you’ll damage matt paint.
- Rinse with clean water on a cloth to remove residue.
- Dry completely with a fan or dehumidifier. Damp walls invite mould straight back.
- Check again in a week. If spots return, look for the moisture source.
Which mould remover should you use?
| Option | Best for | Notes |
|---|---|---|
| Mould remover spray (chlorine-based) | Black mould on bathroom ceilings and tiles | Fast and effective. Strong smell, ventilate well |
| Diluted bleach | White or light-coloured painted walls | Cheap. Can fade coloured paint |
| White vinegar | Light mould, people avoiding bleach | Gentler and slower. May need repeat treatments |
| Anti-fungal wash (paint shops) | Preparing walls before repainting | Used by painters before anti-mould primer |
When cleaning isn’t enough
If the mould has stained the paint, keeps returning, or the paint is bubbling or peeling, cleaning won’t fix it. You need to:
- Find and fix the moisture. Check for leaks from the flat above, pipes, window seals or aircon. For ceiling leaks, see water leaking from your HDB ceiling.
- Scrape off loose paint and treat the area with an anti-fungal wash.
- Seal with an anti-fungal or stain-blocking primer.
- Repaint with anti-mould paint. For ceilings, use an anti-mould ceiling white. Nippon, for example, sells an Odour-less Anti-Mould Ceiling White.
A bathroom ceiling treatment and repaint usually costs $80 to $280, depending on size and how bad the damage is. See wall and ceiling repair.
How to stop mould coming back
- Run the bathroom exhaust fan during showers and for 20 to 30 minutes after
- Leave a 5 cm gap between wardrobes and walls
- Open household shelters and storerooms regularly, or use moisture absorbers
- Service aircons regularly so trunking doesn’t drip
- Keep indoor humidity around 50% to 60% with a dehumidifier in problem rooms
- Don’t dry laundry indoors without ventilation
FAQ
What kills mould on walls permanently?
No cleaner works permanently on its own. Mould returns if the wall stays damp. Remove it, fix the moisture source, then repaint with anti-fungal primer and anti-mould paint.
Is it safe to sleep in a room with mould?
Small patches are common, but mould can trigger allergies and asthma. Clean it promptly and get professional help for large areas.
Can I paint over mould?
No. Mould grows back through normal paint. Clean, dry and treat the wall first.
Why does mould keep coming back on my bathroom ceiling?
Usually poor ventilation or a slow leak from above. Run the exhaust fan longer, and check for a leak if the ceiling has brown water stains.
