How to solve mould problems on your walls: the complete guide
peinture anti moisissure

How to solve mould problems on your walls: the complete guide

Published on 21 June 2026

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FONGEX

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Black or greenish stains appearing in corners, a persistent musty smell, flaking walls… Mould on walls is a nightmare for many owners and tenants. On top of ruining the look of your interior, it can harm your respiratory health.

Fortunately, this problem is not inevitable. Discover where it comes from and how to apply the right anti-humidity treatment to bring back a healthy, protected home.

What is mould and where does it come from?

Mould is made of microscopic fungi (spores) that grow and spread through the air. To settle and proliferate on your plaster, concrete or old paint, it needs one essential trigger: humidity.

The main causes of mould appearing in your home are usually:

  • Condensation: it occurs when warm, humid air in a room meets a cold wall. Typical in poorly ventilated bathrooms and kitchens.
  • Lack of ventilation: permanently closed windows or no ventilation system trap humidity inside.
  • Water infiltration: a crack on the exterior façade or an invisible pipe leak that soaks the wall.
  • Rising damp: ground moisture rising directly into the foundations and walls of ground-floor rooms.

Bathrooms often combine condensation with a desire for change: the perfect time to revamp your bathroom tiling while permanently cleaning up the walls.

Important reminder: before painting, it is essential to identify and repair the source of the infiltration if the problem comes from an external leak. When humidity comes from the wall itself, consider applying an anti-humidity coating to waterproof the wall in depth before painting. Once the wall is repaired, applying a suitable technical product is essential to block residual ambient humidity.

Which anti-humidity paint should you use to fight mould?

Applying a classic paint to an area affected by humidity is a common mistake. The paint will quickly blister and flake, and black stains will reappear within a few weeks.

To clean up your interior for good, you must use a specific anti-mould paint, combined with effective anti-humidity action. This kind of technical coating has fungicidal properties: it acts as an active protective shield that prevents fungal spores from surviving and developing on the paint film.

Discover FONGEX by Prisma Color: the radical anti-humidity solution

To address these issues of black stains and damp walls precisely, Prisma Color developed FONGEX, a major innovation in protective and treatment paints.

An advanced, high-technology chemical formula. FONGEX is not a simple surface coating. It uses a formula specially designed to attack the very structure of micro-organisms. Thanks to its ultra-effective fungicidal agents, it eliminates fungi at the root and prevents their return for a long time. Your walls stay flawless and healthy, year after year.

Aesthetics and performance: no compromise on the finish. With FONGEX, you protect your walls while enhancing your interior decoration. The product comes in three distinct finishes:

  • Matt finish: ideal to hide imperfections on ceilings or bedrooms, with a soft, warm and elegant look.
  • Satin finish: perfect for living areas and hallways, bringing brightness while remaining easy to wash.
  • Gloss finish: recommended for highly exposed rooms such as bathrooms or kitchens, offering an ultra-tight mirror effect and maximum water resistance.

The steps to apply your protective paint

  1. 1Clean and disinfect: clean existing stains with a suitable solution (diluted bleach), then let dry completely.
  2. 2Prepare the surface: if the wall has cracks or holes, fill them with a suitable filler (ANTIFISSURE by Prisma Color).
  3. 3Paint: apply FONGEX paint in two cross-coats to ensure a perfectly even protective barrier.

Don't wait for humidity to damage your health and the value of your property. Ask for advice on FONGEX directly on our site or at our approved resellers across Morocco.

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