#37 – Fasteners and Metal Roofing
May 3, 2017 | Filed under: Metal Roofing 101 Series, Roofing Help, Roofing Help Videos, Roofing Installation, Roofing Materials
When investigating a metal roof for your home, you’re likely to hear about exposed fasteners and concealed fasteners. The terms are self-explanatory, but which is better?
Some metal roofs are designed so that all of the screw heads are exposed. They are visible and exposed to the weather. Other products are designed with concealed fastening system that never see the light of day nor weather. Exposed fastened panels typically have a neoprene washer to help keep the weather out but, even when covered by a metal cap, those neoprene washers break down over time. Exposed fastened products also often do not allow the metal panels to expand and contract with temperature changes. There are some exceptions to that with certain panel designs though. But, in any event, we generally suggest concealed fastened products whenever possible. There is just far less risk of water penetration into the roof system when the fasteners are concealed.
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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Hi Todd,
When installing exposed fasteners, is it acceptable to drill through the bottom of the substrate? I will be installating a 29 gauge metal roof on 15/32 plywood, hi-temp underlayment. The supplier, gave me 1” long screws.
I would always advise you to adhere strictly to recommendations made by your roofing manufacturer. However, as I understand it, drilling from the back side is not unusual. It is also not uncommon to use self-tapping, self-drilling crews but be sure to remove any metal shavings that result.