Without treatment, a cleaned roof can turn green again within a year or two. The spores are still there, in the texture of the tiles.
Biocide changes the answer
A professional biocide treatment kills those spores and keeps stopping new growth. We guarantee our treatment for four years, and in good conditions it keeps working for up to ten.
What shortens it
Shade, overhanging trees, north-facing slopes and nearby fields all bring growth back faster.
A simple rule
Clean properly once, with biocide, then consider a re-treatment after a few years. That keeps the roof clean for far longer than repeated quick washes.
