The most important job of a steel finish is to shield the roof from water, but it must also protect against harmful elements in the environment. Today’s steel coatings are very attractive, and since they do not lose their luster or peel or crack for several decades, they are a great solution for steel building manufacturers and buyers alike. Darker coatings, such as red and blue, can be affected by the sun’s activity so, especially in southern climates, a tarnish protection layer should be applied.

Aluminum and zinc are incorporated into steel roofing finishes for their anti-erosive features. Zinc safeguards the underlying steel, while slowly “melting”� at a pre-calculated rate. The thicker the coating of zinc, the better protection it provides for the rooftop. About every five years, the hot-dip galvanized roofing sections lose a minimal amount of zinc covering. The galvanizing also aids in providing a protective barrier against the weather.

Due to the robust action of zinc plus the barrier characteristic of aluminum, finishes of aluminum-zinc combinations are very popular. One common compound is Galvalume, which was introduced by Bethlehem Steel Corporation more than 35 years ago, and consists of 43.5% zinc, 1.5% silicon, and 55% aluminum. Available as a lock-forming, structural, or commercial variety, Galvalume is a favorite material for structural roofing.

Galfan is comprised of 95% zinc and 5% aluminum; the aluminum and zinc are usually bonded to the steel by means of a continuous hot-dip coating technique. This application is ideal for field flexing when used with panel configuration since it traditionally will not flake or crack.

Aluminum covering, on the other hands, works mainly as a solid barrier. It is a by-product from a chemical-resistant aftereffect of aluminum oxide.

Aluminum-zinc coatings afford great steel protection for many years, and they have gradually overtaken galvanized roofing as the preferred option. These steel roofs can last 30 years before any major maintenance is necessary. Because these finishes are less reactive, they sustain their guard barrier traits much longer than galvanizing.

Galvalume transparent coated panels have taken the place of lubricating oil, which made the rooftop sheets waxy and difficult to manage. The transparent adhesive covering is designed to dissipate gradually over a course of 1-1 1/2 years without chipping or crumbling. Galvalume reduces the staining and marring that can happen with installation and storage of the roof, which eliminates the requirement for lubricating substances.

Finally, be aware that rust decay of roofing is most likely to occur at field-cut corners. Use only steel roofing that is plant milled and finished to reduce the risk of rust. To counteract galvanic processes, zinc and aluminum coatings should not touch unprotected steel. And finally, install an intermediary layer between the coating and adjacent timber decking to prevent damage to the finish.