Slate is a common roofing material for luxury houses and public
buildings. Its attractive look lasts for years, offers maximum
protection, and comes at a high cost. It is heavy which also increases
labor costs so you may want to consider cheaper synthetic options
made from mixtures consisting of rubber, plastic, sand, and/or
cement.
Typically originating in Vermont, authentic slate weighs 500 a
square and costs $500 a square; the imitation slate pans out at
350 and $200 respectively.