For hundreds of years, slate tiles have been used for roofing. Slate possesses all the natural qualities necessary for roof tiles not least because it is easily split into tiles of regular thickness. These tiles are thin enough to create a light roofing material and have the added advantage of being almost completely impermeable to rain and with a high resistance to frost. Slate provides a long lasting roof covering, able to stand up to the effects of atmospheric agents.
Furthermore, it should not be underestimated today that slate, contrary to asbestos-cement tiles which are sometimes erroneously mistaken for slate and which modern regulations state must be removed, is a material which can be considered ecologically perfect. The tiles which were traditionally used by local countrymen in Cogorno and the Val fontanabuona, were not particularly well finished, but the result was roofs of such rustic charm, their beauty is still very much appreciated today. On the contrary, it was a different matter for the slate which was imported to the nearby cities, particularly Genoa. Still today, the rooftops of the historic centre in Genoa are made of traditional rectangular or square slates, while many of the church domes and bell towers have characteristic scaled roofs.