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Roof coating systems occupy a distinct category in commercial roofing claims because they are applied over an existing roof surface rather than replacing it, which raises questions about how to value damage differently than on a standard single-ply or built-up roof. Silicone, acrylic, and polyurethane coatings are the most common types used in restoration work, each formulated for particular substrates and climate conditions, and each with different performance characteristics under hail impact and ultraviolet exposure. A coating system’s manufacturer typically specifies a minimum dry film thickness, measured in mils, required to achieve the rated performance and warranty coverage, and evaluating coating damage often starts with understanding what thickness was actually applied relative to that specification.
Silicone coatings are generally valued for their resistance to ponding water and ultraviolet degradation but can be more susceptible to dirt pickup and, in some formulations, to hail impact damage that shows as a puncture or crater in the coating film without necessarily compromising the substrate beneath it. Acrylic coatings, more commonly used in warmer, drier climates, are less frequently specified in Minnesota’s freeze-thaw environment because standing water and ice can degrade an acrylic coating’s performance over successive winters, an important consideration when evaluating whether an acrylic system’s condition reflects storm damage or a mismatch between the coating type and the regional climate it was installed in.
Determining hail damage on a coated roof requires distinguishing between damage to the coating film itself and damage that has penetrated through to the underlying substrate, since these represent very different repair scopes. A coating can absorb some impact energy and show cosmetic cratering while the membrane or built-up roofing beneath remains functionally intact, in which case recoating the affected area may be sufficient, while a more severe impact that fractures the substrate beneath the coating requires addressing both layers. This distinction is typically confirmed through a core sample or careful probing at representative damage sites, similar to methods used on uncoated membranes but adapted for the additional coating layer.
Restoration coatings are also frequently applied specifically to extend the service life of an aging roof rather than to a new installation, and understanding the roof’s condition and remaining service life before the storm event is relevant background when evaluating a claim, since a coating applied over a substrate already near the end of its functional life presents different considerations than the same coating applied over a roof with many years of expected service remaining. Reinforcing fabric embedded within some coating systems, used at seams, flashings, and detail areas to add tensile strength, can also fail independently of the coating field, and evaluating that fabric’s condition is a distinct part of a thorough inspection.
An appraiser evaluating a coated roof claim generally documents the coating type, application thickness where determinable, and the specific damage pattern observed, relying on manufacturer specifications and standard roofing industry practices to assess the amount of loss once the covered scope has been established by the parties to the claim.
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.