hi tommo
It's mainly used on flat garage / extension roofs instead of felt nowadays, large fibre glass sheet matting rolled into epoxy resin layers, it consists of two layers of matting and then another colour of your choice epoxy resin to finish once dry it's rock hard with no joints ,i chose this as i am about 2 miles from cheesil beach, and when you get a galeforce 9-10 blowing south westerly straight into torbay you don't need to be there believe me , no joints no nail etc , winds don't touch it . hc