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Metal roofing covers a wide range of products, and the evaluation approach differs depending on the system. Standing seam panels are continuous sheets with raised, mechanically or hand crimped seams and concealed fasteners, while exposed fastener panels, sometimes called corrugated or ribbed panels, are screwed directly through the panel face with exposed washered screws. These two systems respond to hail differently. Standing seam panels are generally thicker gauge and often show denting as isolated cosmetic marks in the flat pan areas, while exposed fastener panels can show dents but are also more prone to fastener backout or washer seal failure from repeated wind flexing.
Denting is the most visible and most debated form of metal roof hail damage. Whether a dent is purely cosmetic or represents a functional impairment depends on the panel type, the coating system, and whether the impact has actually cracked or compromised the protective finish, which is the layer that prevents corrosion. A dent in bare metal or one that has visibly fractured the paint or coating at the impact point is a different situation from a dent that has simply deformed the metal without breaking the surface finish, and distinguishing between the two often requires close inspection, sometimes with magnification, at each impact site.
Oil canning is a separate phenomenon that gets confused with hail damage more often than it should. Oil canning is the visible waviness or rippling that appears in the flat areas of a metal panel, particularly on wider standing seam panels, and it is a normal characteristic of light gauge sheet metal responding to thermal expansion, installation tension, and the inherent flatness limitations of the material, not a sign of impact or storm damage. Recognizing oil canning for what it is, rather than treating every ripple as hail related, is a basic but important part of an accurate metal roof evaluation.
One more consideration deserves mention because it is frequently misunderstood: many policies contain cosmetic damage exclusions or endorsements specifically addressing metal roofing, which state that dents affecting only appearance, without impairing the roof’s function, are not a covered loss under that policy’s terms. Whether such an exclusion applies to a given loss is a coverage question that belongs to the carrier and the policy language, not something an appraiser or umpire decides. The appraisal process addresses the amount of loss for damage that is within the scope of the dispute; it does not resolve whether a particular exclusion applies, which is a separate matter outside the appraisal itself.
This article is general education about how the appraisal process commonly works. It is not legal advice, and specific procedures can vary by state and policy.
Russ Lis is a working property insurance appraiser and umpire based in Minnesota, serving clients nationwide. Contact Appraisal Resolution.