In 40 seconds
A professional roof clean in the UK typically costs around £300–£700 for a terraced or semi-detached home and roughly £700–£1,200 for a detached property, before any access extras. Priced by area, hand-removal with biocide tends to run about £10–£20 per square metre and soft washing about £12–£18 per square metre, with a separate biocide treatment usually £150–£300 to slow regrowth. Soft washing is gentler on tiles than pressure washing, which the trade warns can crack or strip them. If a roof can only be reached safely with scaffolding rather than a tower or harness, that adds a significant amount. The honest answer is always a range, because it depends on your roof size, pitch, growth and access.
Most roof-cleaning guidance is published by firms doing the work, so the numbers can be optimistic and the method glossed over. The pages below give sourced cost ranges, explain moss removal and biocide, compare soft washing with pressure washing fairly, and set out how often a roof needs doing — before you take a single quote. We cover cleaning, moss removal, soft washing and biocide only, not roof repairs or re-tiling.