Quonsets have been made with a wide variety of metals throughout history, but these days the majority of North American quonsets are made using GalvalumeTM steel by Arcelormittel. Galvalume is steel that is hot-dipped in a 55% aluminum, 45% zinc alloy. This has two major benefits: The aluminum-zinc coating provides stain resistance The coating is rust-resistant and the reason most quonset buildings come with a rust-perforation warranty