Zinc

Zinc is a bluish-gray metal used architecturally chiefly as a roofing and cladding material, valued for a self-healing protective patina, zinc carbonate, that forms on its surface when exposed to air and moisture and continues to protect the metal even where the surface is scratched. Rolled zinc sheet became a major roofing material in nineteenth-century France, giving many Parisian mansard roofs their characteristic gray sheen, and its light weight, long service life, often exceeding fifty years, and recyclability have sustained its use into contemporary standing-seam roofing and facade cladding on institutional and cultural buildings.