6 min read
Treating damp and mould before painting is not optional in Irish homes — paint over a mouldy wall in Dublin and the black spotting is back within a season, usually worse. This article explains how we identify the cause, treat the surface properly and choose coatings that give the wall a fighting chance, plus when a painter should tell you the problem is not a painting problem at all.
Find the cause before touching paint
Most black mould in Irish bedrooms and bathrooms is condensation: warm moist air meeting a cold surface, typically behind wardrobes, in corners of north-facing rooms and around single-glazed or poorly sealed windows. Penetrating damp shows as a defined patch that darkens after rain. Rising damp is far rarer than people think and shows a tide line low on the wall.
An honest painter will tell you which one you have. If a gutter is overflowing onto a gable or a shower has no working extractor, painting is cosmetic and the problem returns.
Treating the surface properly
Mould is a living growth, so it is killed rather than wiped. We apply a fungicidal wash, leave it the specified dwell time, remove the residue and let the wall dry fully. Painting over live spores with anti-mould paint alone simply feeds them from underneath.
Once dry, stains and any remaining discolouration are sealed with a stain-blocking primer. Emulsion will not hold a damp stain back — it ghosts through, sometimes weeks later.
- —Fungicidal wash with full dwell time
- —Dry the wall out completely before coating
- —Stain-block, don't just add coats of emulsion
- —Use a moisture-tolerant or anti-condensation finish where appropriate
- —Fix ventilation, gutters or seals in parallel
Paint choices that help
In bathrooms, kitchens and utility rooms we use moisture-resistant, washable finishes designed to resist condensation and cleaning. In persistently cold rooms an anti-condensation coating can raise the surface temperature slightly and reduce the dew point problem, though it is a mitigation rather than a cure.
Frequently asked questions
- Will anti-mould paint stop mould coming back?
- It slows regrowth on a properly treated wall, but it cannot fix the moisture source. Ventilation, heating and repairs do the real work; the paint protects the finish.
- Can you paint a wall that is still slightly damp?
- No. Coating a damp wall traps moisture and causes blistering and adhesion failure. We would rather return a week later than hand back a job that fails.