Today’s steel building manufacturers and consumers look for a very durable finish that will not wash out, crack or peel for years. Current premium quality steel finishes do the job and are very attractive. The primary consideration is protection from moisture, and premium quality steel coatings shield the roofing, but also protect against pollution. The sun’s ultraviolet rays can wreak havoc on darker coatings such as blue and red. Particularly in southern climates, application of a good fade-resistant coating is necessary.

Zinc and aluminum are often incorporated into roofing for their anti-erosive properties. As with galvanized premium quality steel, using zinc covering assumes a certain quantity of it “dissolves”� while the underlying steel is not harmed. The higher the desired protection of the building roof, the thicker the layer of zinc should be applied. Galvanizing is another alternate that contributes a guard barrier against the weather; hot-dip galvanized roof components require reapplication about once every 5 years.

Aluminum-zinc finishes have a well-deserved reputation for durability, built upon the long-lasting characteristic of zinc as well as the defensive barrier attributes of aluminum. One common composition is Galvalume; a product introduced by Bethlehem Steel at the beginning of the 1970’s and consists of 43.5% zinc, 55% aluminum, and 1.5% silicon. Galvalume is critical for use on a non-painted roof and it is available in commercial, lock-forming or structural grades.

Galalume is a transparent coating that has largely replaced oil, which made the roofing sheets greasy and hard to manage. Galvalume eliminates the need for lubricating oil, and reduces the discoloration and marring that can occur during placement of the steel components. This transparent adhesive finish is designed to dissolve gradually over a time period of twelve to eighteen months without chipping or crumbling. Conversely, using pure aluminum performs mainly as an inflexible barrier; it is derived from aluminum oxide.

The zinc and aluminum blend is usually adhered to the steel with a continuous hot-dip coating method referred to as Galfan which is composed of a 19:1 ratio of zinc to aluminum. Since it typically will not break or flake, this procedure is great for field flexing as it moves in conjunction with panel structures.

Aluminum-zinc roofing finishes offer great steel protection for several decades, and are much more popular in the 21st century than galvanized rooftops. Industry experts agree that the majority of these steel roofs should last 30 years before any substantial repairs are needed. The reactive qualities of these defensive barriers are greatly reduced over that of galvanized steel.