Causes of Fungal Growth in Paint
Fungal growth (mold, mildew, and algae) on painted surfaces occurs due to a combination of environmental, material, and structural factors:
- Moisture Accumulation – The primary cause, as fungi thrive in damp conditions. Leaks, high humidity (especially >60% RH), condensation, and poor ventilation create ideal environments.
- Low-Quality Paint – Paints lacking fungicides or algaecides are more susceptible.
- Organic Residues – Dirt, dust, and organic matter on surfaces provide nutrients for fungi.
- Poor Surface Preparation – Painting over existing mold traps moisture and promotes regrowth.
- Shaded Areas – North-facing walls and areas behind foliage receive less sunlight.
Treatment and Prevention
- Use a bleach solution (1 part bleach + 3 parts water) to kill surface mold. Scrub with a stiff brush and rinse thoroughly.
- Fix leaks, improve drainage, and ensure proper ventilation.
- Repaint with high-quality acrylic paints containing mildewcides.
- Regularly clean surfaces to remove organic debris.