Can you paint over a wall with mold?

It's not recommended; the mold must first be removed and a protector applied before painting.

Mold and Algae Removers: How to Get Rid of Them and Keep Them From Coming Back

Q: How long does Algacid take to work?

It starts working within about 15 minutes, although rinsing and drying can take longer depending on the surface.

Quick answer: mold and algae (including lichen) grow wherever there's persistent moisture. The solution has two steps: remove what has already grown with a mold remover or anti-algae product, and prevent it from coming back with a specific protector. Applying only the protector over active mold doesn't work: you need to clean first.

Step 1: remove existing mold or algae

Product	What it's for	Surfaces
Nomold	Removes mold that has already formed	Painted walls, natural and artificial stone, cement, terracotta, grout, ceramic, glass
Algacid	Removes algae, mold, and lichen outdoors	Stone, terracotta, exposed-face brick, concrete; works within 15 minutes

Step 2: prevent it from coming back

Product	What it's for	Surfaces
NOMOLD DEFENSE	Active anti-mold protection, also before painting	Natural stone, ceramic, painted walls, cement, grout
Hydrorep Eco	Certified anti-algae barrier for facades	Exterior walls, UV-resistant
Fila Salvadochia	Prevents mold and algae in the constant humidity of showers	Grout lines and shower surfaces

Complete routine for a facade or terrace with algae

Apply Algacid to the affected surface and let it work (visible effect within about 15 minutes).
Rinse with moderate-pressure water and let it dry completely.
Apply Hydrorep Eco as a preventive barrier against algae and moisture.
Repeat the preventive treatment every few years, especially in north-facing or heavily shaded areas.

Why mold comes back if you only clean it

Cleaning removes the visible spores, but if the moisture and conditions that favored it are still there, mold reappears within weeks. That's why it's worth always applying a protector after cleaning, not just once the problem is already visible.

Frequently asked questions

Can I use bleach to remove mold from the shower?

Bleach bleaches the stain but doesn't address the root of the problem, and repeated use can damage grout and silicone seals. A specific mold remover like Nomold, followed by a protector like Fila Salvadochia, gives a longer-lasting result.

How long does Algacid take to work?

It starts working within about 15 minutes, although final rinsing and complete drying can take longer depending on the surface and the amount of algae buildup.

Can you paint directly over a wall with damp stains?

It's not recommended. You should first address the cause of the moisture, remove the existing mold, and apply a protector like NOMOLD DEFENSE before painting, to keep the stain from reappearing under the new paint.