How to get rid of mould on walls: the short answer
To get rid of mould on walls, first deal with the damp causing it, then spray the mould with a mould remover, leave it for about 10 minutes and wipe it off with a damp disposable cloth. Let the wall dry fully and check it again after a week.
Most wall mould in UK homes is condensation: warm, wet air settling on the coldest surface in the room. Cleaning takes ten minutes. Keeping it off is about the air and the temperature of the wall.
Honest bit
No spray stops mould forever on its own. If the wall stays damp, mould comes back, whatever you clean it with. Treat the moisture and the mould together.What you need
Nothing specialist. Get this together before you start so you are not walking mouldy cloths through the house.
Gloves
Household rubber or nitrile gloves.
Eye protection
Glasses or goggles, especially for ceilings.
A mask, if sensitive
Worth it if you have asthma or allergies.
Throwaway cloths
Old cloths or paper towels you can bin.
A bin bag
To seal the used cloths straight away.
A mould remover spray
One that is safe on paint. See our mould remover for walls guide.
How to remove mould from walls, step by step
Seven steps. The first and the last matter as much as the cleaning in the middle.
- 1
Find and fix the cause first
Mould on walls is a moisture problem. Look for condensation on windows, a leak, a blocked extractor fan or washing drying on the radiator. Clean without changing anything and you are booking the next clean.
- 2
Protect yourself and the room
Put on gloves and eye protection. Open a window if you can. Pull furniture away from the wall so you can reach the whole patch, and lay an old towel on the floor or skirting board.
- 3
Spray and leave it for 10 minutes
Spray the mould and a hand width of clean wall around it, because growth spreads further than you can see. Then leave it alone for 10 minutes. Contact time is what does the work. With Mould Check mould remover spray there is no scrubbing and no rinsing.
- 4
Wipe with a damp disposable cloth. Do not dry brush
Wipe gently in one direction with a damp cloth, folding it to a clean side as you go. A dry brush or dry cloth throws spores into the air and onto the rest of the room.
- 5
Let the wall dry fully
Leave the furniture off the wall, keep air moving and heat the room gently if it is cold. A wall that stays damp grows mould again.
- 6
Bag and bin the cloths
Put the used cloths straight into the bin bag, tie it and take it outside. Do not rinse them out in the sink and reuse them on another wall.
- 7
Check again after a week
Look at the same spot seven days later. Clean wall means you are winning. New dots mean the moisture is still there, so go back to step one.
Why we built Mould Check for this
Mould Check is hypochlorous acid at pH 6 to 7, close to neutral. It is not a bleach, so it does not strip paint or colour. It is COSHH free, has no harsh fumes, and you spray, wait 10 minutes and wipe, with no rinsing. To the BS EN 1650 standard, hypochlorous acid achieved 100% removal of common household moulds including Aspergillus niger, Penicillium and Stachybotrys chartarum.How to treat mould on walls by surface
The method stays the same. What changes is how much liquid the surface can take and how gently you wipe.
How to remove mould from painted walls
Bleach based sprays can leave pale patches on emulsion, especially coloured paint. Use a spray that is safe on paint, mist it on rather than soaking the wall, and wipe lightly. Matt emulsion marks more easily than silk, so test a hidden area first. Our guide to mould removers for walls covers what to look for.
How to get rid of mould on wallpaper
Wallpaper is porous and does not like being wet. Spray lightly, leave it, then blot rather than rub. If the paper is bubbling, peeling or stained from behind, the mould is underneath and the paper usually needs to come off.
Mould on bare plaster
Bare plaster soaks liquid up like a sponge, so growth can sit below the surface. Treat it, give it plenty of drying time, and treat again before you paint. Crumbling, soft or blown plaster needs repairing, not just cleaning.
How to get rid of mould on ceilings
Wear eye protection, stand on something steady and spray in short bursts so it does not drip. A flat mop with a damp disposable cloth wrapped round it saves your neck. Ceiling mould under a bathroom or loft can mean a leak or missing insulation above.
What people suggest, and what actually happens
Ask on any forum how to get rid of mould on walls and you get the same seven answers. Some genuinely work.
| What people suggest | What actually happens |
|---|---|
| White vinegarPartly | Acetic acid kills surface growth slowly. Does not remove the stain. Needs repeating. |
| Vinegar with lemon juicePartly | No better than vinegar alone. |
| Bleach and waterSurface only | Bleaches the pigment. On porous surfaces the growth survives. |
| Hydrogen peroxide, 6% minimumWorks | Genuinely effective, decomposes quickly, bleaches fabric and hair. |
| HG mould removerWorks | Works, and it is bleach-based, so the porous-surface limit applies. |
| Anti-mould paintPartly | Slows regrowth. Painting over live mould does not stop it. |
| New silicone sealantWorks | The right answer when the sealant is the problem, not the wall. |
If you want the detail on the two most common answers, read does vinegar kill mould and does bleach kill mould.
How to get rid of mould on walls permanently
Straight answer: you cannot clean mould away permanently. You can only take away the conditions it needs. Mould needs moisture, and in most homes the moisture is condensation. Reduce that and treated walls stay clean.
Cut condensation
Wipe windows dry each morning, put lids on pans and close the kitchen or bathroom door while they are steamy.
Ventilate
Run extractor fans during and after cooking and showers, keep trickle vents open and open a window for a few minutes each day.
Dry washing outside
Drying washing indoors puts a lot of water into the air. If you must, use one room with the door shut and the window open.
Keep a steady heat
Low, steady heating keeps walls above the temperature where moisture condenses. Cold rooms grow mould fastest.
Leave a gap
Keep wardrobes, beds and sofas a few centimetres off outside walls so air can move behind them.
Use a dehumidifier
In bedrooms and flats with poor airflow, a dehumidifier pulls out water you cannot ventilate away.
When it is not condensation
Some damp needs a repair, not a habit change. A patch that spreads after rain points to penetrating damp: a leaking gutter, cracked render or failed pointing. A tide mark low on a ground floor wall can be rising damp. Leaking pipes and roofs cause mould too. No spray fixes these. Get the repair done, let the wall dry, then treat what is left.
Why mould keeps coming back in the same place
If you clean a wall and the same patch grows back within weeks, that spot is colder than the rest of the room. Moist air condenses on the coldest surface it can find, the way a cold can of drink gets wet on the outside.
- Corners of outside walls lose heat on two sides, so they stay cooler.
- Around windows the frame and reveal often form a thermal bridge, a path where heat escapes faster than through the rest of the wall.
- Behind wardrobes and beds the wall never gets warm air on it.
There is a second reason too: what you cleaned it with. Bleach is very good at making mould look gone, because it whitens the pigment. On porous surfaces like paint and plaster the growth can survive underneath and come straight back. The colour fades, the mould stays.
What not to do
Dry brush or vacuum it
Brushing dry mould sends spores across the room. Always wipe damp.
Paint over it
Paint traps live mould underneath and it comes back through. Read what to do about painted over mould.
Mix bleach and vinegar
Bleach with any acid releases chlorine gas. It is a common forum suggestion and a dangerous one. See why you should never mix bleach and vinegar.
Scrub until the plaster breaks
Hard scrubbing roughens paint and plaster. Let contact time do the work.
If you rent: tell your landlord in writing
You can clean small patches of condensation mould yourself. But if it keeps coming back, is spreading, or comes from a leak, damp wall or broken extractor fan, that is a repair, and repairs are your landlord's job.
- Report it in writing, by email or through the landlord's portal, so there is a dated record.
- Take photos before you clean, with something in shot for scale, and keep them.
If you rent from a council or housing association in England, Awaab's Law now requires social landlords to investigate and fix damp and mould hazards within set timeframes. Our COSHH and mould guide explains what that means for how landlords and contractors treat it in occupied homes.
When to get professional help
DIY is fine for small patches on sound walls. Call in a specialist when:
Large areas
More than a patch or two, or mould across several rooms.
It keeps returning
Back within weeks after a proper treatment and better ventilation.
Damaged plaster
Soft, crumbling or blown plaster, or damp you cannot trace.
For a survey and professional mould remediation, we recommend Mould Specialists UK. They can find the source of the damp, not just treat the wall.
Mould on walls: frequently asked questions
Because that spot is where the wall is coldest or wettest. Corners, window reveals and the wall behind a wardrobe stay cooler than the rest of the room, so warm moist air condenses there first. Cleaning removes the growth, but unless you reduce the moisture or warm that surface up, the conditions that grew it are still there.
A good mould remover spray is usually quicker and less hassle. Vinegar kills some surface mould slowly and leaves the stain. Bleach whitens the stain, but on porous surfaces like plaster and paint the growth can survive underneath. Hydrogen peroxide at 6% or more works too. A hypochlorous acid spray like Mould Check is near neutral, safe on paint and needs no rinsing, which suits walls in lived-in rooms.
Mould Check has no harsh fumes and is COSHH free, so you can use it with the windows shut and with people at home, including children, pets and pregnant tenants. We still suggest opening a window afterwards if you can, to help the room dry out.
The cleaning takes minutes: spray, leave for 10 minutes, wipe. The wall then needs to dry fully, which can take a few hours. If spots reappear within a week, the moisture problem has not been fixed yet.
Not until the mould has been treated and the wall is completely dry. Paint does not kill live mould, and it usually grows back through the new coat within weeks. Clean it, let it dry, fix the damp, and only then repaint, ideally with an anti-mould paint.
For a small patch, gloves and eye protection are the main things. If you have asthma, allergies or a sensitive chest, wear a well fitting mask, because wiping can release spores. Avoid dry brushing, which sends far more into the air. For large areas, get professional help.