The Real Cost of Neglecting Your Roof

A roof clean costs between $699 and $850 for a typical Newcastle home. A full roof replacement costs $15,000 to $35,000. This is the importance of removing lichen before it's too late.

What lichen actually does to tiles

Lichen is not just cosmetic. It is a symbiotic organism — part algae, part fungus — that anchors itself to the tile surface using root-like structures called rhizines. These penetrate the glaze of concrete and terracotta tiles. As the lichen expands and contracts with heat and moisture cycles, it opens micro-fractures in the tile surface.

Water enters those fractures. In Newcastle, temperatures swing from 35°C in summer to near zero on winter nights. Water in a crack expands when it freezes and contracts when it dries. Do this a few hundred times over five years and the tile breaks.

A broken tile is not just a replacement tile. It's how water enters your roof — and once it gets behind the sarking, it begins to rot away the timber. Timber rot and mould remediation in a roof cavity can cost more than the roof itself.

When to clean and when it is too late

If your tiles have lichen but are still structurally sound, a soft wash treatment will kill the growth and stop the damage. The dead lichen washes off in rain over the following weeks. Results last three to five years before retreatment.

If the tiles are already cracking, a clean will not fix them. You need a tiler to replace the broken tiles before applying any treatment.

If more than 30% of tiles are cracked, re-roofing is usually the more economical option. We will tell you this honestly if we inspect your roof.

How this affects your Home Insurance

Home insurance policies typically exclude damage from lack of maintenance. A roof with visible lichen and moss that leaks during a storm may not be covered. An insurer can argue that the damage was gradual and preventable. Regular cleaning creates a documented maintenance record. Whether or not that matters to your insurer depends on your policy, but it is worth knowing.

What not to do

Do not pressure wash a tiled roof. High-pressure water strips the protective granule coating from concrete tiles and forces water under laps. It will void any remaining warranty on the tiles and accelerate the damage you are trying to prevent. This is one of the most common mistakes we see — homeowners or budget operators using pressure on surfaces that need a soft treatment.