Cleaning roofs
In the fullness of time roof tiles are colonised by moss, lichen and a host of other species. It is deleterious to the material and appears poorly maintained. The mix of species is called “biofilm”.
After the treatment, the dead biofilm slowly disperses revealing the original appearance of the tiles. The self cleansing can take between a few weeks and a few months depending on the exposure and porosity of the roofing material.