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Skylights are one of the few roof penetrations large enough to require a dedicated, manufacturer-engineered flashing system rather than a field-fabricated detail, and understanding how those systems are built helps explain why skylight-related roof leaks and claims can be more complicated than they first appear. Most residential skylights sold today come with a flashing kit matched to that specific model and to the roof pitch it will be installed on, consisting of a head flashing at the top, step flashing pieces down the sides, and a sill or apron flashing across the bottom, all designed to integrate with a specific frame profile.
Older skylights and some commercial-style units instead sit on a raised wooden curb built on site, with flashing wrapped around the curb in much the same layered sequence used at a chimney: base flashing at the bottom, step flashing up the sides, and counterflashing or a cap that laps over the top of the step flashing where it meets the skylight frame or curb cladding. Curb-mounted skylights depend heavily on the condition of that curb framing, since wood exposed to years of condensation or minor water intrusion can deteriorate in ways that are not visible until the skylight and its flashing are removed.
The curb height itself, often specified as a minimum of a few inches above the roof plane, matters in areas that see regular snow accumulation, since a curb built too low relative to the local snow load and drifting pattern can allow snowmelt to back up against the skylight frame in a way a taller curb would not. This is one reason skylight placement and curb height on homes across snowier parts of the Midwest sometimes differ from manufacturer minimums used in milder climates.
Replacing shingles around an existing skylight without disturbing the flashing kit is possible in some cases, particularly where the flashing is in good physical condition and the skylight model is unchanged, but manufacturer instructions frequently call for a new flashing kit whenever the surrounding roofing is replaced, since the kits are not generally designed to be reused indefinitely and the shingle work necessarily disturbs the step flashing pieces integrated into each course. This is a construction and product specification question separate from whether a specific storm event caused the damage prompting the roof replacement in the first place.
Inspecting a skylight after a hailstorm or wind event involves checking the glazing or acrylic dome for cracks or impact marks, examining the frame and any exposed metal flashing for denting, and looking at the interior ceiling or skylight shaft for staining that might indicate a leak, whether recent or long-standing. Because skylights combine a manufactured product, a structural curb or frame, and a flashing system that ties into the surrounding shingle field, a thorough inspection typically draws on knowledge of general roofing practice as well as skylight-specific installation requirements published by the manufacturer, and documenting each of these elements separately gives the parties to a claim a clear physical record to work from.
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.