When choosing a metal roof to stand up against hail storms, there are a few key factors to consider: the panel's gauge (or thickness), its tensile strength, whether or not it has a UL Impact rating, and the panel's design itself. Each of these factors contribute to a metal roof's effectiveness against hailstorms.
It's important to note that while there is no 100% hail-proof roofing solution, Bridger Steel's metal panels are hail resistant and are one of the top-recommended options for protecting your home in this type of environment.
When it comes to protecting a roof, the thickness of the metal panel is a key factor to resisting large-sized hail stones. Bridger Steel recommends a minimum of a 26 gauge steel roofing panel to survive a harsh hail storm. A thicker metal panel will resist punctures and impacts, plus form stronger seams between panels.
When choosing the right roof to protect against a hail storm, it's important to understand your options regarding tensile strength. A higher tensile strength will hold up better to dents and surface damage, but has a higher likelihood of puncturing in the case of massive hail stones.
A lower tensile strength will deform and stretch under the largest hail stones, rather than breaking. In more common small to medium sized hail, a lower tensile strength will still deform. Bridger Steel recommends using a higher tensile strength metal, combined with a strong panel that's unlikely to puncture or tear.
The UL 2218: Standard for Impact Resistance of Prepared Roof Covering Materials Rating is a testing process where a panel is subjected to a impact that simulates a hailstone. This simulation is achieved by taking a 1.25 - 2 inch steel ball and dropping it from a height of 12 feet above the panel. The panel is tested in various areas — edges, seams, unsupported joints, etc. — in order to test the full scope of the panels.
A Class 4 rating means the panel did not crack when struck twice in the same location by the steel ball. This is the highest rating available for a metal roofing panel.
While this test provides one of the best gauges of how a roof will hold up against a hail storm, even this extensive test does not guarantee a material or product will hold up against a severe hail storm. Hailstone can travel at incredibly high speed rates, creating unbelievable impacts. While a panel can resist two strikes in the same location, a hailstorm will likely result in many, many more strikes to the same location. This can eventually cause some serious damage to the roofing material (which is why there is no truly 100% hail-resistant roofing solution, just options that come pretty close).
Fortunately, baseball-sized hailstorms don't typically occur all the time. For the majority of homes, this UL 2218 rating is considered by professionals and insurance companies to be the highest level of protection by a roof covering materials available.
The last factor in determining a good choice for a hail resistant roof is choosing the right type of metal panel itself.
In most cases, a Corrugated panel is the best option for pure protection. The corrugation and wavy pattern design helps deflect and hide any deformities that may occur from a hail storm. Bridger Steel's top-recommended Corrugated panel is our 7/8" Structural Corrugated panel. This is because this is our strongest panel, and alongside obtaining a UL 2218 impact rating, it's also our highest rated panel against wind uplifts (up to 260 mph).
For those interested in a Standing Seam panel, we recommend the 2" Structural Mechanical Lock with Striations, and double-seamed for added protection. The double-seamed rib will provide the best possible protection for your roof from a seamed product. The Striations will help give the panel additional rigidity, and help to hide smaller imperfections better than a flat design.