Panels last; connections do not
A metal roof panel - properly coated, correctly specified for the coast - will outlast most of the things attached to it. What ages on a metal roof is the system of fasteners, seams, closures and sealant that turns a pile of panels into a weathertight surface. Maintenance on a metal roof is maintenance of those.
Fasteners
On an exposed-fastener roof, every screw has a rubber or neoprene washer under its head. That washer is what seals the hole the screw made. It is also a small piece of rubber in the Florida sun, and it cracks, shrinks and flattens over years. The screw itself can back out as the panel moves with temperature, and a screw that is proud by a few millimetres has a washer that is not sealing anything. Check: for backed-out screws, for washers that are visibly cracked or missing, for rust staining below a fastener.
On a standing-seam roof, the fasteners are concealed under the seams, which is a large part of why standing seam costs more and lasts longer. But there are still exposed fasteners at the trims, the ridge and the penetrations, and those need the same look.
Seams and laps
Where panels overlap side-to-side or end-to-end, the joint depends on either a mechanical lock, a factory sealant bead, or field-applied sealant. Look for laps that have opened, for sealant that has hardened and pulled away, and for any lap where the water would run into the joint rather than over it.
Sealant
Metal roofs use sealant at the ridge closures, the end laps, the penetrations and the trims. Good sealant on a metal roof lasts years, not decades. When it chalks, cracks or separates from the metal, it needs cutting out and replacing - not a fresh bead on top of the old one, which is the most common bad repair on metal.
Penetrations
Pipe boots on a metal roof have to fit a profiled surface, which is why metal-roof boots are a different product from shingle boots. A shingle boot forced onto a metal panel will leak. So will any penetration that was cut after the roof went on and sealed with a tube of caulk.
Cadence
Annually, at minimum, with attention to the fasteners and sealant. Metal roofs do not give many warning signs from the ground - a backed-out screw does not show from the street - so this is a system where the annual look does most of the work. Repairs on metal are scoped separately, and they are almost always small if the annual look is happening.
Fasteners, seams, closures and sealant - photographed on every visit, so the one that backed out this year gets fixed this year.
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