Pressure washing a roof removes the moss, lichen, algae and dirt that hold moisture against the tiles, block valleys and gutters and make a roof look old. Done properly it starts with an inspection and uses a method matched to the tile, because the wrong pressure can crack weak tiles or drive water under the laps. It is also the first step of every restoration and repaint.
The short answer
- Removes moss, lichen and dirt that hold water against the tiles
- Inspect first, then match the method to the tile’s condition
- Some tile makers, Monier among them, advise against pressure washers on roofs
- Disconnect rainwater tank inlets before cleaning
- hipages figures quoted by Canstar put roof cleaning at about $250 to $500
Why roofs need cleaning
- Moisture: moss and lichen hold water against the tile surface, which speeds wear on porous concrete tiles
- Drainage: growth and debris in valleys and gutters back water up under the tiles
- Spotting problems: on a clean roof, cracked tiles, failed pointing and rusted valleys are easy to see
- Preparation: roof coatings will not bond to a dirty or mossy surface
- Appearance: a clean roof makes the whole house look better
Monier explains that moss and lichen settle where moisture and dirt build up: shaded and south-facing roof planes, valleys under trees and the lower courses where water slows down.
Sources: Monier: Roof cleaning and maintenance.
Pressure cleaning done right
- Inspect firstCheck tile condition, pointing and valleys, and note anything already broken before cleaning starts.
- Match the method to the tileSound tiles can take a thorough clean; fragile, weathered or glazed tiles need more care, and sometimes cleaning is not the right answer.
- Work safelyOur crews clean from behind our own temporary safety rail, never just a harness and a ladder.
- Replace what the clean exposesCracked tiles found during cleaning are replaced from our yards.
- Clear gutters and valleysDebris washed off the roof is cleared from gutters rather than left to block downpipes.
Monier advises against pressure washers on its roof tiles, because the wrong pressure, nozzle or angle can etch a weak tile, crack brittle ones or drive water up under the laps. Pressure is a tool, not the goal.
Sources: Monier: Roof cleaning and maintenance.
Roof looking tired?
Book a free inspection. We will tell you whether it needs a clean, a restoration or nothing yet.
If you have a rainwater tank
Health guidance on rainwater tanks says the inlet should be easy to detach so the tank can be bypassed, and that roofs and gutters should be kept clean. Disconnect the inlet before cleaning so debris and cleaning water do not run into the tank, and keep it off after a recoat until the coating has cured.
Why DIY roof pressure washing is risky
- Too much pressure can crack tiles or push water under them
- Wet, mossy tiles are extremely slippery
- Ladder work with a pressure hose is a fall waiting to happen
- Debris washed into gutters can block downpipes and overflow
WorkSafe Victoria’s compliance code treats falls from roofs as one of the most serious risks in housing construction. Leave the roof to a crew with edge protection.
Sources: WorkSafe Victoria: Prevention of falls in housing construction.
How often should a roof be cleaned?
There is no fixed timetable. Roofs under trees, on shaded or south-facing planes, and older concrete roofs with worn coatings grow moss and lichen faster. Health guidance recommends keeping roofs and gutters clean twice a year where you collect rainwater, and Monier recommends a professional inspection around every five years. Clean when growth is building up in valleys and on the lower courses, not on a calendar.
Sources: enHealth: Guidance on the use of rainwater tanks; Monier: Roof cleaning and maintenance.
What roof cleaning costs
hipages figures quoted by Canstar put roof cleaning at about $250 to $500, depending on the condition of the roof. Size, pitch, height, access and how much growth there is all affect the price. Cleaning is included in every restoration; see our restoration cost guide.
These are market ranges from published Australian price guides, not Royce Roofing prices. Every roof is different. We give you a fixed written quote after a free inspection.
Sources: Canstar: How much does a roof restoration cost in 2026? (citing hipages).
Cleaning versus restoration
| Cleaning | Restoration | |
|---|---|---|
| What it does | Removes moss, lichen and dirt | Cleaning plus repairs, rebed and repoint, valleys and, for concrete tiles, recoating |
| When it fits | Sound roof, mainly dirty | Roof with tired pointing, faded tiles or rusting valleys |
| Read more | Roof pressure cleaning | Roof restoration |
If your roof is faded or showing wear as well as dirt, combining the clean with a restoration avoids paying for the set-up twice.
WorkSafe Victoria’s compliance code for housing construction puts edge protection such as guard railing ahead of harnesses and ladders when controlling the risk of falls from a roof. Our crews set up our own temporary safety rail, ladder guards and, where there are old skylights, safety nets before anyone works on the roof. Every crew member holds a working at heights qualification.
Common questions
Is pressure washing safe for roof tiles?
It can be, if the method suits the tile. Some tile makers, Monier among them, advise against pressure washers because the wrong pressure can crack weak tiles or force water under the laps. Inspect first.
How often should a roof be pressure cleaned?
There is no fixed schedule. Clean when moss and lichen build up, which happens faster on shaded roofs, under trees and on older concrete tiles.
How much does roof cleaning cost?
hipages figures quoted by Canstar put roof cleaning at about $250 to $500, depending on the roof’s condition, size and access.
Should I disconnect my rainwater tank before roof cleaning?
Yes. Disconnect the inlet so debris and cleaning water do not run into the tank.
Can I pressure wash my own roof?
It is risky: wet, mossy tiles are slippery and too much pressure cracks tiles. Leave it to a crew with edge protection.
What is the difference between roof cleaning and restoration?
Cleaning removes growth and dirt. A restoration includes cleaning plus repairs, rebed and repoint, valleys and, for concrete tiles, recoating.
Related
Sources: Monier: Roof cleaning and maintenance; enHealth: Guidance on the use of rainwater tanks; WorkSafe Victoria: Prevention of falls in housing construction; Canstar: How much does a roof restoration cost in 2026? (citing hipages).
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