Cleaning Terracotta and Concrete Tile Roofs in Adelaide
Terracotta and concrete tile roofs in Adelaide are cleaned by soft washing with a biocide, never by high pressure. High pressure strips the terracotta glaze and the concrete tile coating, forces water under the tiles and voids the warranty. Expect $400 to $900 depending on size, pitch and how heavy the moss and lichen are.
Key takeaways
- Tile roofs are soft washed. High pressure strips the glaze off terracotta and the coating off concrete tiles.
- A biocide treatment kills moss and lichen at the root so it does not return in a season.
- Heritage terracotta in North Adelaide, Norwood and Unley is brittle and needs minimal foot traffic.
- Indicative cost is $400 to $900 for a standard Adelaide tile roof.
Why tile roofs demand a soft wash
Terracotta tiles have a baked-on glaze that makes them shed water and resist growth. That glaze is the tile's protection, and high pressure strips it off. Once it is gone the terracotta is porous, absorbs moisture, and grows moss faster than it did before, so a high-pressure blast makes a tile roof worse in the medium term, not better. Concrete tiles have a factory colour coating that does a similar job, and high pressure chews it off, leaving a faded, rough, moss-friendly surface.
The correct method for both is a soft wash: low pressure plus a biocide that kills the growth chemically. This cleans the roof thoroughly without touching the glaze or coating, and it keeps the tiles doing their job of keeping water out of your home.
Moss and lichen in the tile valleys
Tiled roofs trap moss and lichen in the overlaps and valleys where moisture sits. Scraping or rinsing the green off leaves the roots and spores behind, and in Adelaide's climate it regrows within a season. The definitive fix is a biocide treatment that kills the growth at the root and keeps working after the operator leaves.
This is especially true in the Adelaide Hills. Tile roofs in Stirling, Aldgate and Mount Barker sit under damp tree cover and grow lichen aggressively. A rinse-only clean in the Hills is a waste of money. A biocide treatment is the only approach that gives lasting results, and heavy lichen often keeps clearing for weeks afterwards as the dead growth weathers off.
Heritage terracotta needs a careful operator
Adelaide's older suburbs, North Adelaide, Norwood, Unley, Prospect and parts of Walkerville, are full of decades-old terracotta and the occasional slate roof. These tiles are brittle, often no longer manufactured in matching profiles, and expensive or impossible to replace cleanly. A heavy-footed operator cracks them just by walking the roof wrong.
The specialists we refer for heritage roofs minimise foot traffic, work off the correct access points, and use the gentlest effective soft-wash approach. Matching a careful operator to a fragile heritage roof is exactly the kind of local knowledge a generic franchise or an unvetted casual does not bring.
What it costs and how to get quotes
A standard Adelaide tile roof runs $400 to $900 to soft wash and treat. Steep pitch, 2-storey access and heavy Hills lichen push toward the top; a single-storey roof with light growth sits lower.
We do not clean roofs ourselves. Pressure Cleaning Adelaide connects you with vetted local specialists who soft wash tile roofs and treat moss with a biocide. Tell us your suburb and tile type and we will arrange up to 3 free quotes so you can compare price and method before booking.