Concrete or clay tiles – moss and lichen

Causes

Insufficient cleaning, or roof remains damp due to overhanging branches

Listed under: finishes, tiles, concrete and cement, concrete tiles, Roof, cladding, fixings and hardware, fixings, roof cladding, concrete or clay tiles

Cause

Insufficient cleaning, or roof remains damp due to overhanging branches

Repair

  • cut  back overhanging branches
  • 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
  • be careful where the water for drinking is collected from the roof – downpipes should be disconnected during cleaning and subsequent rinsing.
  • nail a 150 mm wide copper strip along the roof ridge or 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 – this can force water up between the tiles.

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