Guardianand#039;s slate roofing is a new solution to tile roofing on domestic and commercial properties. Each individual ridge has a length of 445mm and each side of the roof angle measures at 150mm. See the CAD drawing above for more details.If needed, these ridges can be cut with a fine-toothed handsaw or a jigsaw. A fully installed composite roofing system is impermeable, is A Rated to British Building Standards and has a Class IV hail rating.Click here to view our full installation guide for composite slate roofing tiles.