Metal Roofing and Wind Resistance for Homeowners
Over the past few years, weather changes have brought longer and more violent storm seasons to coastal areas and further inland. Our country has responded with requirements like stricter building codes and Fortified Housing guidelines. While Mother Nature can dish out a lot, homeowners can protect their properties, families, and belongings.
Usually, after a major wind event, you see images casting metal roofs in a good light and a bad light. Some pictures show entire metal roofs torn away from buildings, ending up in the parking lot or on the building next door. But, you also see aerial images of devastated neighborhoods where the few remaining homes have metal roofs. So, which is true – are metal roofs wind-resistant or not?
A well-installed and well-designed metal roof can be as wind-resistant as the structure itself. Due to how metal panels attach to the structure, they are prone to damage if they shift or move. Panels can disengage from each other, and fasteners can pull out of lumber or sheet metal. However, virtually any roofing material will fail in the event of structural movement.
But when the structure stays sound, the interlocking nature of metal panels holds them in place despite very high winds and uplift pressures.
Generally, after hurricanes and major wind events, building performance is linked to the structure’s age, the building codes in place when it was built, and the quality of the construction.
Fastening Systems Make a Difference in Wind Resistance
Metal roofs come in two general categories – exposed fastener metal roofs and concealed fastener metal roofs. Exposed fastener panels are directly screwed to the structure with rubber grommets for water protection. Concealed fastener roofs usually have interlocking panels and are available in a wide range of designs, including products that look like slate, wood shakes, and shingles.
While exposed fastener products offer great wind resistance when first installed, this diminishes over time as thermal movement loosens the fasteners and “wallows” out the fastener holes. For this reason, the best long-term wind resistance comes from concealed fastener systems, despite the slightly superior initial performance of exposed fasteners.
If windblown debris strikes an interlocking concealed fastener roof, it can cause the panels to disengage, leading to a domino effect of wind damage across the roof. My advice to property owners is to ensure that everything in the building’s surrounding area is secured or stored away before a major wind event.
Where exposed fastener metal roofs lose wind resistance with age, concealed fastener products typically stay wind resistant as they age.
How wind resistant is metal roofing?
So, how wind resistant is metal roofing? Many products are warranted for 120 mph winds, provided the product is installed correctly. Most metal roofs can also have their installation engineered for higher wind pressures using additional fasteners, larger fasteners, or sealants and adhesives.
Here’s a short video on the subject of wind resistance.
While wind events are always unpredictable, property owners who choose metal roofs enjoy superior protection from high winds. I am happy to consult with you regarding wind-resistant roofing options for your house.
Todd Miller has spent his entire career in the metal building products manufacturing industry. He is president of Isaiah Industries, an organization recognized as one of the world’s leading metal roofing manufacturers. Todd is currently Vice President of the MRA (Metal Roofing Association) and a Past Chair of MCA (Metal Construction Association). Through his website, he strives to raise the bar on standards and practices to provide property owners with the best possible products for successful roofing projects.
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