Moss & Algae Treatment

Removing growth that traps moisture and shortens the life of your roof covering

Moss and algae growth is more than a cosmetic issue — trapped under tile laps and around ridge lines, it holds moisture against the roof covering long after rain has stopped, which is what actually shortens a roof's working life over time.

Moss thrives where a roof stays damp and shaded for long periods — north-facing pitches that see little direct sun, and roofs under or near overhanging trees, are the classic conditions, since both keep moisture sitting on the surface far longer than a south-facing, open pitch would. Once established, moss spreads along tile and slate laps and around ridge and hip lines, and the problem it causes isn't really about the moss itself — it's about what the moss holds in place. A cushion of moss keeps the tile surface wet for days after rain has stopped, which accelerates weathering, and on some tile types it can lift tiles slightly at their overlaps, letting water track underneath rather than shedding off the surface. This is exactly why scraping moss off the surface alone usually isn't enough: it removes the visible growth but leaves spores and root structure behind, which regrows within a season or two, and scraping carelessly can also damage the tile surface itself. A proper treatment combines careful mechanical removal of the growth with a biocide wash to kill remaining spores and slow regrowth, plus a check of gutters and valleys afterwards, since moss debris is one of the most common causes of blocked and overflowing guttering.