What exactly is Galvalume, besides what a metal roof is made of? According to the website (www.galvalume.com), Galvalume sheet steel is a 55% Al-Zn coated sheet steel product.

Hmm… okay. What does that even mean?

It means Galvalume is basically sheet steel coated with 55% aluminum and 45% zinc alloy. This makes it durable and ensures it will not corrode for the life of the product. This magical combination of aluminum and zinc has been displacing corrugated metal roofing for years.

It’s also a bit more high-tech than standard metal roofs of yore. According to steelroofing.com;

Both Galvalume and galvanized sheet steels are made by a “continuous hot dip” process. Coils of cold rolled steel are welded end-to-end and processed continuously on the coating line at speeds up to 600 feet per minute. The uncoiled sheet is first cleaned to remove rolling oils and mill dirt, and to reduce surface oxides so that the surface will accept the coating. These continuous sheets are first fed into a molten coating bath contained in an open top, brick-lined heated pot. The sheet then passes around a roller submerged in the coating bath and exits the bath vertically, pulling out with it an envelope of the coating material. As it exits, the sheet proceeds through a pair of opposing air knives, which are positioned above the bath and equidistant from the surface of the sheet. Most modern production lines have a coating thickness gauge feed-back control, which automatically adjusts knife air pressure and position to ensure that a uniform coating is applied. Various finishing steps are carried out to complete the process, after which the sheet is wrapped around a reel into a coated steel coil.

Got that? Even if you don’t understand all the nuances of Galvalume production, you can still rest assured that the reasoning behind the manufacturing process is there to ensure production of the best roofing material possible. Lets go back to steelroofing.com;

Galvalume sheet is an ideal material for roofing because of its extraordinary outdoor corrosion resistance and subsequent long life. It can be readily roll-formed into a variety of panels, as well as formed and stamped into tile and shingle facsimiles. It can also be factory painted to impart color and extend durability (see color chart here)! Most importantly, it can be used in modern day steel roof designs which are strong, yet light weight. And unlike conventional nonmetallic roof systems, Galvalume sheet roofs won’t crack and peel when subjected to the sun’s rays and various weather conditions.