Have you ever been inside a warehouse, factory, or other industrial building where you look up and see the roof from the inside? This is a good example of structural metal roofing, which is when metal panels are installed over open framing or on structures that span long lengths and are attached directly to the frame or purlins (additional support beams added to the roof frame). Like structural applications, barns and other agricultural buildings are common uses for metal roofing. Agricultural structures traditionally use an exposed fastener or lap seam profile, which is when the ends of the panels overlap each other and have sealant or exposed fasteners holding the two panels together.