Anti-mould paint contains a fungicide that helps stop mould growing on the painted surface, so it’s a useful choice for bathrooms and kitchens. But it doesn’t remove the moisture that causes mould, and unless that cause is fixed, the mould comes back.
If you’ve repainted a bathroom ceiling before and watched the black spots return by the next winter, that’s why. Paint treats the symptom; ventilation, heating and repairs treat the cause. This guide explains what anti-mould paint can and can’t do, how to work out where the moisture is coming from, how to treat mould safely and how to paint a bathroom so it lasts. It’s one of our painting and decorating guides, written by decorators who would rather fix a room once than repaint it every winter.
What Anti-Mould Paint Does - and What It Can’t Do
Anti-mould paint has a fungicide built into the paint film. When mould spores land on the surface, the fungicide discourages them from taking hold, so it takes longer for black spots to appear on the paint.
How long that protection lasts depends on the product. Some manufacturers make claims for a set period, but conditions in your room - how much steam, how often it’s cleaned, how well it’s ventilated - make a big difference. Treat any stated period as the best case, not a guarantee.
There are three things anti-mould paint can’t do:
- Kill mould that’s already growing. Live mould has to be treated before you paint.
- Dry out a wet wall. If the wall is damp, paint won’t stick well and mould will find a way through.
- Fix a leak. A dripping pipe or a gap in the roof will keep feeding the problem.
Paint straight over live mould and you seal it in. It carries on growing underneath and reappears through the new finish, often within weeks.
It’s also worth knowing how to look after anti-mould paint once it’s on. Clean it gently with a soft cloth and mild, soapy water rather than scrubbing with abrasive cleaners, which wear the surface down faster. Wipe off any black spots as soon as they appear instead of leaving them to spread, and treat their return as a sign that the room needs more ventilation, not a thicker coat of paint.
Why Mould Keeps Coming Back: Find the Cause First
Mould needs moisture. Work out where the moisture comes from and you know what will fix it. These are the five usual causes, with the signs to look for.
| Cause | Typical signs | What actually fixes it | Will paint help? |
|---|---|---|---|
| Condensation | Black spots in corners, on cold outside walls, window reveals and bathroom ceilings; worse in winter; wet windows in the morning | Better ventilation, working extraction and steady heating | Yes, as a back-up once the moisture is under control |
| Poor ventilation | No extractor, a fan that’s too weak or switched off too soon, trickle vents closed | Working extraction and airflow | Not on its own |
| Penetrating damp | A patch on an outside wall that grows or darkens after rain; faulty gutters, pointing, render or roof | Repair the outside fault, then let the wall dry | No, not until it’s repaired |
| Rising damp | Damp and tide marks low on ground-floor walls, sometimes with white salts | A damp survey by a qualified, independent surveyor | No |
| Leaks | A localised patch near pipes, or on a ceiling under a bathroom | A plumber or roofer first, then stain block and repaint | Only after the repair |
In most bathrooms, condensation and poor ventilation are the culprits. If the pattern doesn’t fit, or you suspect penetrating or rising damp, get it looked at by a qualified surveyor before spending money on decorating.
Condensation is the most common of all, and it’s worth understanding why. Every shower, bath, pan of pasta and load of washing dried indoors puts water into the air. When that warm, damp air meets a cold surface - an outside wall, a window, a ceiling below a cold loft - it turns back into water. Where the surface stays damp for long enough, mould grows. That’s why it shows up first in corners, behind furniture against outside walls and on ceilings above showers.
Ventilation: The Fix That Matters Most in Bathrooms
Good ventilation removes damp air before it settles on cold surfaces. It’s free or cheap compared with repainting every year.
- Run the extractor every time. Switch it on during every shower or bath and leave it running afterwards. A fan with an overrun timer keeps going for a set time after you leave.
- Check it’s actually working. Hold a single sheet of tissue against the grille while it runs. A working fan should hold it there. If the tissue drops, the fan or its ducting needs looking at.
- Keep the door shut while showering. That keeps steam in the bathroom where the fan can remove it, instead of spreading through the house.
- Open a window afterwards if you can, to clear the last of the moisture.
- Keep trickle vents open on the windows, all year round.
- Wipe down tiles, screens and windows after a shower to cut the amount of water left to evaporate.
- Keep the room evenly heated in winter. Cold walls attract condensation.
The rest of the house matters too. If bedrooms have mould on outside walls or around windows, the moisture usually comes from everyday living - breathing overnight, cooking, and clothes dried on radiators. Dry washing outside or in a ventilated room with the door shut, use the cooker hood when cooking, leave a small gap between large furniture and outside walls, and open bedroom windows for a while each morning. Small habits like these do more to stop mould than any paint.
If your bathroom has no extractor or the fan isn’t up to the job, that’s one for an electrician. We don’t fit extractor fans, but we’re happy to repaint once a new one is in.
How to Treat Mould Before You Paint
- Protect yourself. Wear rubber gloves, goggles and a mask, and open a window.
- Don’t dry-brush or sand the mould. That spreads spores into the air and around the room.
- Apply a fungicidal mould wash as the label directs, and leave it for the time stated.
- Wipe or rinse if the label tells you to.
- Let the surface dry completely. Give it time, especially in a bathroom.
- Seal any remaining dark marks. Use stain block over mould marks so they don’t show through the new paint.
- Then paint with a bathroom or anti-mould emulsion.
A word on bleach: household bleach can whiten mould without fully treating porous surfaces, so the wall looks clean but the mould comes back. A product sold as a fungicidal mould wash is made for this job.
A word on health: mould spores can affect breathing. If anyone in the home has asthma, allergies, a respiratory condition or a weakened immune system, or the mould covers a large area, get professional help rather than tackling it yourself. The NHS publishes guidance on damp and mould and its effects on health, which is worth reading if you’re concerned.
Choosing the Best Paint for a Bathroom
Once the cause is under control, choose a paint that stands up to moisture and wiping.
| Paint | Where to use it | Why |
|---|---|---|
| Bathroom paint | Walls and ceilings in most bathrooms | Moisture-resistant and wipeable, often with a fungicide |
| Anti-mould emulsion | Rooms with a history of mould, once the cause is fixed | Fungicide slows regrowth on the surface |
| Durable matt or soft sheen | Walls that need regular wiping | Soft sheen resists moisture better; durable matt hides more |
| Eggshell or satin | Woodwork, boxing-in, doors and window boards | Hard-wearing and easy to clean |
| Bathroom or anti-mould paint on the ceiling | Ceilings | Steam rises, so the ceiling takes the most moisture |
Kitchens follow the same logic as bathrooms: steam from cooking and grease from the hob mean a wipeable, moisture-resistant paint is worth the extra cost, especially on the ceiling and the wall behind the cooker.
As a rule, more sheen means easier wiping but more visible lumps and bumps. Our guide to paint finishes explained compares each sheen level in detail.
How to Paint a Bathroom Step by Step
- Fix the cause and treat any mould first, as above.
- Let the room dry out. Avoid showering in it beforehand for as long as the paint tin advises, and keep the window open.
- Remove or mask fittings. Take down mirrors, cabinets and accessories where you can, and mask taps, tiles and the bath edge.
- Fill, sand and clean. Fill cracks and holes, sand smooth, then wipe down to remove dust, soap residue and grease.
- Seal new plaster. Any new or patched plaster needs a mist coat on new plaster before the topcoats.
- Cut in carefully along tiles, the bath, the shower tray and the ceiling line. Good, sharp edges make a bathroom look finished.
- Apply two coats of bathroom or anti-mould paint, letting the first dry fully.
- Let it cure for the time on the tin before using the shower. Steam on fresh paint can cause streaks and weak spots.
Mouldy sealant around the bath or shower tray needs cutting out and replacing separately. Paint won’t fix it.
Mould in Rented Homes: Advice for Landlords
Landlords have legal duties to deal with damp and mould in the homes they rent out, and that usually means fixing the cause, not just the marks. In England, damp and mould growth is one of the hazards councils assess under the Housing Health and Safety Rating System, and newer rules - often called Awaab’s Law - set timescales for social landlords to act. The requirements are changing, so check current GOV.UK guidance for the position that applies to your property. This is general information, not legal advice.
The practical point is simple: repainting between tenancies without fixing ventilation, heating or leaks just hides the problem until next winter. Sort the cause, treat the mould, stain-block the marks and then repaint. Our page on end of tenancy and landlord painting in Birmingham explains how we fit this work around changeovers.
When to Call a Decorator - and When to Call Someone Else
Once the cause is fixed, our interior painting and decorating in Birmingham team can take on:
- A full bathroom or kitchen redecoration
- High ceilings and stairwells
- Mould-stained ceilings that need treating, stain-blocking and repainting
- Whole-house clean-ups after a winter of condensation
Call someone else first for:
- Leaks - a plumber or roofer
- Suspected rising or penetrating damp - a damp surveyor
- Extractor fans - an electrician
If we visit and see signs of an active damp problem, we’ll tell you rather than paint over it. A finish that fails in six months doesn’t help anyone.
Related Guides
- Stain block paint - sealing water, smoke, nicotine and mould marks so they don’t bleed through.
- Paint finishes explained - matt, soft sheen, eggshell, satin and gloss compared.
- Mist coats and painting new plaster - sealing fresh plaster before the topcoats.
Browse all painting and decorating guides for more advice.
Anti-Mould Paint and Bathroom Painting Questions
Does anti-mould paint actually work?
Yes, as a surface defence. The fungicide in the paint film slows mould growing back on the painted surface, which makes it a sensible choice for bathrooms and kitchens. What it can't do is stop condensation, dry out a damp wall or fix a leak. If the moisture is still there, mould will eventually return, whatever paint is on the wall.
How long does anti-mould paint last?
It depends on the product, so check what the manufacturer states for the paint you're using, and treat it as a guide rather than a promise. Protection also wears down with age and repeated scrubbing. The longer-lasting fix is cutting the moisture: good extraction, steady heating and sorting out any leaks or damp.
Can you paint over black mould?
No. Paint over live mould and it grows back through the new finish, often within weeks. Treat it with a fungicidal mould wash as the label directs, let the surface dry completely, seal any dark marks left behind with stain block, then paint. And find out why it grew in the first place.
Is bleach enough to kill mould before painting?
Not reliably. Household bleach can whiten mould on the surface without fully treating it on porous surfaces like plaster and painted walls, so it can look clean and still come back. A product sold as a fungicidal mould wash is designed for the job. Follow the label, wear gloves and keep the room ventilated.
What is the best paint for a bathroom ceiling?
A bathroom paint or an anti-mould emulsion. Steam rises, so the ceiling takes more moisture than any wall and is often the first place mould appears. If the ceiling has been newly plastered, mist coat it first. If there are old water or mould marks, stain block them before the topcoats.
Should bathroom paint be matt or silk?
A soft sheen or a dedicated bathroom paint resists moisture and wipes clean better than a standard matt. Matt hides lumps and bumps better but can mark more easily in a damp room. Many bathroom paints now have a low-sheen finish that does both reasonably well. Our guide to paint finishes compares them.
Why does mould keep coming back after painting?
Because the moisture source is still there. Most often it's condensation from showers, cooking and drying clothes, combined with poor ventilation and cold walls. Sometimes it's a leak or damp coming through the wall. The cause table on this page explains the signs of each and what actually fixes it.
Who is responsible for mould in a rented home?
Landlords have legal duties to deal with damp and mould in the homes they let, and the rules are being tightened, so check current GOV.UK guidance for the latest position. This is general information, not legal advice. For help with repainting once the cause is fixed, see our end of tenancy and landlord painting page.