To remove mould from painted walls, kill and wash off the growth, fix the moisture feeding it, let the wall dry, and repaint the area in a washable finish — painting over mould without treating it just lets it grow back through the new coat. Mould on a wall is a moisture-and-shade problem, not a paint fault. This guide covers how to clean it, why it keeps returning, and how to repaint so it stays gone. For the underlying damp, see the damp walls guide.
Why does mould grow on painted walls?
Mould needs moisture, low light and something to feed on — so it thrives on damp, shaded walls: bathrooms, kitchens, south-facing exteriors, behind furniture and anywhere with a leak, rising damp or condensation. The paint itself is rarely the cause; it is the damp behind or on the surface. That is why cleaning alone never lasts — if the moisture stays, the mould comes back. The lasting fix always has two parts: remove the growth, and remove the water that feeds it.
How do you remove mould from a wall?
Wash the affected area with a vinegar solution, scrub the growth off, and rinse — white vinegar kills common household mould without the harshness of bleach and does not just bleach the stain while leaving the spores. Wear gloves and a mask, ventilate the room, and apply the vinegar (neat or diluted with a little water) to the mouldy area. Give it time to work, scrub with a brush or cloth, then rinse and let the wall dry completely. Bleach lightens the mark but often leaves living mould behind; a vinegar wash and physical removal deals with the growth itself.
Bleach or vinegar — which actually kills mould?
On a painted, porous wall, vinegar is the better choice: bleach mostly removes the colour of the stain while its water content soaks in and can feed regrowth, whereas vinegar penetrates and kills the mould itself. Bleach earns its reputation on hard, non-porous surfaces like tiles and glass, but on plaster and paint it bleaches the surface stain and leaves living roots behind, so the mould darkens again in weeks. A plain white vinegar wash, left to work and then scrubbed and rinsed, deals with the organism rather than just its colour. Whichever you use, ventilate well, never mix bleach with other cleaners, and remember that no cleaner substitutes for fixing the damp — it only buys time until the moisture is resolved.
Why does painting over mould fail?
Fresh paint over live mould traps it against the wall with a food source and moisture underneath, so it keeps growing and pushes the new coat off within months. You end up with staining, blistering and peeling on top of the original problem. Mould must be killed, removed and the surface dried before any paint goes on. Equally, if the damp source is still active, even a perfectly cleaned and repainted wall will grow mould again — which is why the next step matters as much as the cleaning.
How do you stop mould coming back?
Find and fix the moisture source — a leak, rising damp, poor drainage or condensation — and improve airflow and light to the wall; without this, no paint will keep mould away. Repair leaking gutters, pipes and roofs; address rising or penetrating damp with the correct waterproofing system; and reduce condensation in wet rooms with ventilation and extraction. Move furniture off cold external walls so air can circulate. The waterproofing guide and damp walls guide cover fixing the water side properly.
What paint should you use in mould-prone areas?
Repaint high-risk areas in a washable, wipeable finish — a sheen or enamel surface sheds moisture and lets you clean off early growth before it takes hold, unlike a flat matt that holds dirt and damp. For bathrooms, kitchens and shaded walls, High Sheen or Eggshell Enamel give a hard, wipe-clean surface; High Gloss Enamel is the most scrubbable of all for trim and high-touch spots. A washable finish will not defeat an active damp problem — but on a dry, sound wall it makes the surface far easier to keep mould-free.
How do you repaint after treating mould?
Once the wall is clean, the damp is fixed and the surface is fully dry, prepare and prime any bare or damaged areas, then apply your washable topcoat. Make sure the wall has dried out completely — painting a still-damp wall repeats the whole problem. Fill and prime patches where the old paint failed, then coat edge to edge in the washable finish. In a bathroom or kitchen, take the coating right into the corners and around fittings where moisture collects. Good ventilation while the paint cures helps it harden properly.
When is mould a bigger problem than paint?
If mould keeps returning after cleaning and repainting, or covers large areas, the real issue is structural damp or ventilation — solve that before spending on more paint. Persistent rising damp, a hidden leak or a room that cannot shed humidity will beat any coating. In those cases the money is better spent on the waterproofing, drainage or ventilation fix first; the repaint is the last step, not the solution. If you are unsure which you are dealing with, our team can help — call +27 84 985 6141 or visit our paint shops in Table View and Edenvale.
