Today’s steel paints are plentiful and attractive. Additionally, most of them not only protect the roof against moisture, but they also guard it against harmful elements in the environment. Invariably, customers are looking for a highly durable finish that will not fade, crack or peel for a substantial period of time—and this is exactly what your manufacturer or supplier can provide.
The southern climates especially require paint with a good fading resistance because darker colors, such as red and blue, can be destroyed by ultraviolet radiation. Aluminum and zinc are very popular for applying to steel roofs because of their anti-corrosive characteristics. As with galvanized steel, if you use a zinc coating you should expect a certain amount to “dissolve” away while preserving the underlying steel. The deeper the coating of zinc, the longer the pre-engineered steel roofing will be protected. A barrier against the elements is also added by the galvanizing. The hot-dip grade of galvanized roof panels reduces by a small amount of coating every five years.
Counter to this, employing aluminum coating operates mainly as a solid barrier. It is a chemical-resistant byproduct of aluminum oxide. The aluminum and zinc are usually fused to the steel by means of a continuous hot-dip coating procedure known as Galfan which is made up of a 19:1 ratio of zinc to aluminum. This procedure is great for field flexing and forming of panels since it customarily will not flake or crack.
Evident in the longevity of zinc as well as the boundary protection of aluminum is the growing popularity of an aluminum-zinc finish. Galvalume constitutes such a composition. Bethlehem Steel Corporation launched Galvalume in the early ’70s and it contains 43.5% zinc, 1.5% silicon, and 55% aluminum. It is popular as a plain structural roof and is available as a lock-forming, commercial, or structural grade.
Aluminum-zinc coatings afford excellent steel protection for a long time. Many people claim they protect for up to 30 years before maintenance or repairs are required. These coatings maintain their protective cover more than galvanizing and are only remotely reactive. Zinc-aluminum covered roofs are more popular than a galvanized pre-engineered steel roof at current.
Eradicating the need to apply oil, which made the roofing sheets slippery and troublesome to handle, is the introduction of Galvalume transparent-coated parts. The clear coating eliminates the need for lubricating substances and also decreases the staining and marring that can develop during installation of the steel pieces. Over a period of 12 to 18 months any clear adhesive covering is intended to rub off gradually without powdering or flaking.
Lastly, rust decay can occur at the field-cut perimeters of a rooftop. Factory milled and completed pre-engineered steel roofing is very much recommended. A buffering area should be considered and you should prevent contact with timber decking as this can be damaging. Furthermore, zinc and aluminum finishes, to impede galvanic activity, should not be in direct contact with unprotected steel.
Ask your manufacturer or supplier about the many paints and protective coatings available for your pre-engineered steel roof. Make sure that any you choose are suitable for the climate and weather loads in your area.