Roof cleaning & moss removal · A focused guide
Is pressure washing suitable for clay roof tiles?
Published by Big Ben Roofing Ltd
Do not assume pressure washing suits a clay tiled roof. Marley advises against it for clay tiles because the spray can damage the covering. Ask the cleaning contractor to identify the actual tile and explain a suitable method before work is agreed. The roof condition, nearby details and management of debris also belong in that discussion. Avoid testing an area yourself or treating a visibly brighter sample as proof that the method is appropriate.
Identify the tile before the equipment
An old specification or spare tile record may help establish the covering, but roof colour alone is not a product identification. Tell the contractor about cracked tiles, earlier repairs and any active leak. Ask how these will be assessed before cleaning begins. If the covering is uncertain, the proposed method should remain open until that uncertainty is addressed rather than selected from a photograph alone.
Discuss the outcome without promising a new roof
Cleaning should have an agreed purpose, such as addressing an identified accumulation, rather than guaranteeing a uniform new appearance. Ask how fragile areas, wall junctions and gutters will be treated within the proposal. Request a record of defects identified before work so cleaning and repair responsibilities are clear. Keep the method description with the quote; photographs of a different roof do not establish suitability for yours.
Useful details to record
- Share the tile specification if it is already known.
- Ask how the manufacturer’s cleaning guidance was considered.
- Report damaged tiles and existing water entry beforehand.
- Agree the cleaning purpose, method and debris handling.
Use information already available from indoors or ground level. Do not climb onto the roof or disturb materials to complete this checklist.
Does using a smaller pressure washer make the method acceptable?
Equipment size alone does not establish suitability. Ask the contractor to explain the proposed process for the identified tile and roof condition, with reference to relevant manufacturer guidance, rather than accepting a general assurance about reduced pressure.
Background reading
General guidance helps frame the questions. The cause, suitable materials and scope depend on inspection of the particular roof.
Related questions
Should cracked or slipped tiles be assessed before roof cleaning?
Separate visible covering defects from a cleaning brief and agree how existing damage will be recorded before a roof surface is disturbed.
Does visible moss need removing if the roof is not leaking?
Separate appearance, drainage and roof condition when deciding whether visible moss calls for cleaning or a more limited maintenance task.
Discuss what you have noticed
Include your postcode, the affected roof section and when the concern appears. The team will review the enquiry and confirm the next step, scope and availability.
Request a roofing assessment