An older flat roof can be susceptible to moss growth as rainwater can pool on the surface. Stone chippings also provide moss with shade and can retain moisture; the perfect conditions for moss to grow, especially if in the shade. It is important to remove this moss as it may cause damage to the coating as it spreads and the surface expands and contracts with changes in the weather, causing small imperfections and allowing water ingress. Clumps of moss can break free and roll into gutters and cause blockages.

Given the construction of a flat roof, especially if old, it may not be safe to walk on the surface and so you should either seek the advice of a roofing contractor or use one of our telescopic brooms and extendable sprayer lances to tackle the job from the floor or edge of the roof.

Brush any loose stone chippings to one side and remove any loose moss, leaves or twigs so that you can treat the surface. Once treated you can return the chippings to an even coverage over the surface.