The Metal Roofing Alliance and our members talk a great deal about quality. In fact, it’s so important to us that “Investment Grade Roofing” is part of our logo. Contractors may wonder why it matters so much – isn’t one metal roof just as good as any other? The answer is NO in capital letters!
Veterans of the industry know that the metal roofing products on the market can vary greatly in quality and value. We’ve all seen sub-par products, such as those intended for agricultural applications, improperly installed in a residential neighborhood.
As a condition of joining the MRA, all of our member manufacturers agree to adhere to strict industry codes regarding the quality of the products sold into the residential market.
The Importance of Coatings
The type of coating applied to the sheet steel is a key factor in choosing the right product for residential use. Two types of metallic coatings are used in metal roofing to prevent rust — zinc (galvanized) or zinc plus aluminum (galvalume). These coatings provide a sacrificial barrier against the elements which prevents the iron from rusting. Because it sacrifices itself to form zinc oxide or aluminum oxide, the thicker this layer, the more protection against red rust there will be. There are differing amounts of metallic coating used on sheet steel depending upon its final product application.
The numbers G-40; G-60; and G-90 refer to the ounces of zinc per 100 square feet of sheet steel coated. (top and bottom) So G-90 will have 90 ounces of Zinc- 45 ounces on each side per 100 square feet of roofing sheet steel.
For galvanized products, the MRA recommends a minimum of G-90 be used. For galvalume product used in residential application, the MRA recommends a minimum metallic coating of AZ-50. This is in accordance with the Guidelines for Residential Metal Roofing published by the Metal Construction Association.
However, if you want to be sure that you’re purchasing quality metal roofing for use on homes, the easiest thing you can do is to ask whether the manufacturer is an MRA member. If the answer is yes, you’ll know that the product you’ll install is rated for residential applications. A strong MRA member manufacturer can be your best friend in this business, providing training, specs for fasteners, underlayments, and ongoing support.
To learn more, visit our website: www.MetalRoofing.com