written by on 20/10/2014
Suggest many giving poor ratings were too impatient. I painted some roof pantiles after wire brushing off the moss. After a few weeks the black mould disappeared and the tiles continued to lighten for several months after. I suspect it works best on porous substrates as the rain can't wash it away. I find power wash first if you can and then Patio Magic. Periodic treatment and the mould won't come back.