Drive around Sussex and you'll see plenty of roofs with a green coat, especially under trees and on north-facing slopes. Is it a problem?
When moss is just cosmetic
A thin layer of moss or lichen on a sound roof is mostly cosmetic. It doesn't automatically mean anything is wrong.
When it matters
- It holds water against the tiles, which keeps them damp and can speed up wear on older, porous tiles.
- It blocks gutters and downpipes as clumps wash down, leading to overflows and damp walls.
- It can lift tiles. Thick cushions under tile edges can let wind-driven rain in, and in frost the trapped water expands.
Why we avoid pressure washing tiles
High-pressure jet washing makes a roof look clean quickly, but it can strip the surface off concrete and clay tiles, wash out mortar, and drive water under the tiles. Many tile manufacturers advise against it.
How safe moss removal works
- Moss is removed by hand with scrapers and brushes.
- The roof is treated with a biocide to kill remaining spores and slow regrowth.
- Gutters and downpipes are cleared of the debris.
- Any slipped or broken tiles spotted along the way are reported or repaired.
Keeping it away
Cutting back overhanging branches helps, as does regular gutter clearing and occasional re-treatment.
Find out more about our moss removal and roof cleaning, or get a quote.