Mould vs mildew: what's the difference and does it matter?

They're related — but not the same

Mildew is technically a type of mould, but in everyday use the words describe different things. Mildew is the light, surface growth you see on tiles, grout and fabrics. "Mould" usually refers to the darker, deeper growth that penetrates materials and signals a more serious moisture problem. Knowing which you have tells you how worried to be.

How to tell them apart

Mildew: flat, powdery, white/grey/yellow, sits on the surface, wipes away fairly easily, common in bathrooms. Mould: often black, green or fuzzy, raised or slimy, grows into plaster, wood or fabric, harder to remove, and frequently comes with a musty smell. If it wipes clean and doesn't return, it was likely mildew. If it's dark, keeps coming back, or the surface is damaged, it's the deeper kind — see dangerous or cosmetic.

Does the difference matter?

It does. Mildew is mostly a cleaning and ventilation issue you can often handle yourself. Deeper mould signals trapped moisture and can damage the structure and affect health, especially black mould. Treating serious mould as if it were mildew — a quick wipe — is why it keeps returning.

What to do about each

For mildew: clean it, improve ventilation, and keep the area dry. For deeper mould: the moisture source must be found and fixed, and the material treated with mould treatment or, where it's soaked in, professional mould removal. If you're not sure which you're dealing with, an mould inspection settles it and measures the moisture behind the surface.

Not sure if it's mildew or something worse? book a €75 inspection and we'll tell you, or call +357 96 738151.