copper sheeting
A roof covering of large copper sheets or slats joined together, excluding small overlapping copper shingles.
Copper sheet roofing is constructed out of large pieces of rolled copper, usually in the form of sheets or slats which are welded, fitted, or nailed to each other. It does not refer to roofing made of small, overlapping copper shingles. Copper is prized as a roofing material for the bright green color it attains after two or three decades of weathering.
Copper is the principal sheet metal, and the large units meet at fitted or fixed joints. Weathering can change their color without changing the roofing material.
Small overlapping copper plates are metal shingles. A coating that gives another material a copper-like color does not make that covering copper sheeting.