Hi, I've got an extension with a flat roof covered with fibre glass about 2 years old. For the 2nd time in 6 months I've had to clean the roof of green algae, there is about a 3 inch fibre glass lip over the edge of the extension and this seems to be causing green algae runs down the exterior rendered walls, it looks awful.
Anyone any ideas to stop this happening please? Thanks
Anyone any ideas to stop this happening please? Thanks