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Storefront and curtain wall glazing systems are a common source of disagreement in commercial hail and wind claims, largely because damage to glass is not always as visible or as simple to categorize as damage to a roof or a siding panel. Most modern commercial storefronts use insulated glass units, two or more panes of glass separated by a sealed air or gas-filled space, often with tempered or laminated glass required by code depending on the size, location, and height of the opening. A single unit can be damaged in ways that range from an obvious crack to a compromised seal that lets moisture into the airspace over time, producing fogging that may not appear immediately after the event that caused it.
Hail impact on glass presents a particular evaluation challenge because tempered glass, which is required in most storefront and door applications for safety reasons, does not always show an impact mark the way a shingle or a metal panel does. It may develop a stress fracture that starts small and propagates over days or weeks, or it may show no visible sign at all despite an impact that damaged the seal on an insulated unit. Appraisers and estimators working these claims often rely on documented impact evidence elsewhere on the building, such as denting on adjacent metal trim, mullions, or HVAC equipment, to help establish whether a hail event of sufficient size and force reached the glazing in question.
Aluminum storefront framing itself is a separate line item from the glass it holds, and damage assessment has to account for both. Extruded aluminum mullions and door frames can be dented or bent by wind-driven debris, hail, or impact from displaced building components, and a bent frame member often requires replacement of the entire framing run rather than a spot repair, since storefront systems are engineered as continuous assemblies with specific tolerances for glazing to seat properly. Matching an existing anodized or painted finish on aluminum framing raises the same kind of uniformity questions that siding and roofing claims raise, particularly on older storefronts where the original finish color or process may no longer be available.
Curtain wall systems on larger commercial buildings add another layer of complexity, since they are typically engineered assemblies tied into the building’s structural frame with specific wind load and water infiltration performance requirements. Replacing a damaged curtain wall panel is not always a matter of ordering a like-kind piece of glass; it may require coordination with the original system manufacturer or a licensed glazing contractor familiar with that specific product line, and lead times for custom or discontinued systems can be substantial. These realities affect both the cost estimate and the reasonable timeline for completing repairs, both of which are relevant when an appraisal panel is valuing the loss.
Testing standards from organizations such as ASTM International govern impact resistance and safety glazing requirements, and referencing the applicable standard for the glass type in question, whether tempered, laminated, or wired, helps ground an estimate in something more concrete than visual impression alone. Building code requirements for safety glazing near doors, stairs, and low sill heights can also dictate that a repair be brought up to a current standard even if the original installation predated that requirement, which is a code compliance question distinct from, but relevant to, the scope of covered repairs.
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.