Pressure washing looks impressive but can lift tile coatings, drive water under sheeting, and blast paint off eaves. For most residential roofs, soft washing is safer and equally effective.
What is roof soft washing?
Soft washing combines low-pressure water with biodegradable cleaning agents that kill moss, lichen, mould and grime at the root, so the chemistry does the work rather than the pressure. It is safe on tiles, Colorbond® and paintwork, will not force water under sheeting, and suits roofs with solar panels.
Soft washing uses low-pressure water combined with biodegradable cleaning agents to lift moss, lichen, mould and grime from the roof surface. The chemistry does the work, not the pressure.
- Low pressure — safe on tiles, Colorbond® and paintwork
- Kills moss and lichen at the root, so it doesn't grow back as fast
- Won't drive water under roof sheeting
- Safer for solar panels and skylights
When is pressure washing the right choice?
High pressure suits driveways, concrete paths and some hardstand surfaces where the surface cannot be damaged. On a residential roof it is almost always the wrong tool, because it lifts tile coatings, drives water under sheeting and strips paint from eaves and fascia boards.
Pressure washing has its place — driveways, concrete paths, some hardstand surfaces. On a residential roof, it's almost always the wrong tool.
How do you know your roof needs a wash?
Look for black streaks or a green tint across the roof, lichen patches on tiles, visible moss in valleys and along ridges, or a drop in solar output caused by shading and grime. Any of those on a South Coast home means a soft wash is due.
Common triggers Coast Flow sees on South Coast homes.
- Black streaks or green tint on the roof
- Lichen patches on tiles
- Visible moss in valleys or ridges
- Reduced solar output from panel shading
Key takeaways
- Soft washing is the safe default for residential roofs
- Pressure washing can strip tile coatings and drive water under sheeting
- Combine roof washing with a gutter clean for best results
- Ask what pressure and chemicals will be used before booking any roof clean