... it more than ten years. High quality roofing slate. All of our roofing slate confirms the standard of BS680, ASTM C406, ... S1 and EN 12326 standards.Slate With low water absorption, easy installation, good acid resistance, ... efflorescence proof, heat-resistance and antifreeze, it is widely used in outdoor roofing, paver, and cladding.Size is: 400x250, ...