Asphalt shingles – moss and lichen
Listed under: Roof, cladding, moisture, roof cladding, asphalt shingles
Cause
Insufficient cleaning
Repair
- clean roof regularly with a solution of 1 part household bleach to 4 parts water to restrict moss growth; brush on with a stiff broom or wire brush. Do not use where the water is collected for drinking.
- nail a 150 mm wide copper strip along the roof ridge; alternatively install copper ridge flashing – the copper oxide solution produced by the rain is toxic and will restrict moss growth. Check that copper is compatible with adjacent building materials such as guttering and downpipes.
- Do not waterblast as this can force water up between the tiles and damage the chip surface.
Cause
The roof remains damp due to overhanging branches
Repair
- cut back any overhanging branches to reduce the likelihood of debris on the roof
- clean roof regularly with a solution of 1 part household bleach to 4 parts water to restrict moss growth; brush on with a stiff broom or wire brush. Do not use where the water is collected for drinking.
- nail a 150 mm wide copper strip along the roof ridge; alternatively install copper ridge flashing – the copper oxide solution produced by the rain is toxic and will restrict moss growth. Check that copper is compatible with adjacent building materials such as guttering and downpipes.
- Do not waterblast as this can force water up between the tiles and damage the chip surface.