How to tell if mould is dangerous or just cosmetic

Cosmetic vs structural — the key difference

Not every black spot means disaster. Surface (cosmetic) mould sits on top of paint, silicone or grout in naturally damp areas and wipes away. Structural mould has taken hold in the material itself — plaster, drywall or timber — and signals a moisture problem behind the surface. Telling them apart saves you both unnecessary worry and unnecessary cost.

Signs it's probably just cosmetic

It's usually surface-level if: the patch is small (coin to palm sized), it's in an obviously wet spot like shower silicone or a window reveal, it wipes off and the surface underneath is firm and sound, and it doesn't return within a couple of weeks. This kind of mould is often a ventilation and cleaning issue.

Signs it's more serious

Treat it as a real problem if you see any of these: it covers a large area or several rooms; it keeps coming back after cleaning; there's a persistent musty smell; the wall or ceiling is soft, discoloured, or the plaster is bubbling or blown; or it's on a bedroom wall where people sleep. These point to moisture inside the structure — often rising damp, a leak, or serious condensation.

When to get it checked

If you're seeing the warning signs above, or you simply can't tell, an mould inspection removes the guesswork. We measure the moisture in the wall, find the source, and tell you plainly whether it's a wipe-down or a treatment job — with a fixed quote either way. There's no point paying for professional mould removal you don't need, and no sense ignoring a problem that's spreading.

book a €75 inspection and know for certain, or call +357 96 738151 and describe what you're seeing.