Hail Damage, Backed-Out Fasteners, and a Partial Roof Repair
After a hailstorm, an owner of a 15-year-old 6/12 roof with 5,000 sq ft of 24-gauge steel shingles reports dents on the south slope, paint missing on about 20 panels, and a leak at a 4-in. plumbing vent boot. The roof was installed over 15/32-in. OSB with a synthetic underlayment; fasteners are 1-1/4-in. roofing screws with neoprene washers. The insurer’s adjuster says the dents are cosmetic and authorizes replacement of only the vent boot and 20 panels. The owner wants the whole roof replaced. The contractor finds 24 fasteners backed out along the south rake, rust staining at the vent, and several panels with elongated slots; the manufacturer’s warranty is 30-year limited and requires installation per published instructions. The contractor proposes to replace the 20 panels, caulk the backed-out fasteners, and reuse the existing vent boot with a larger sealant collar. No permit is mentioned.
1. How would you distinguish cosmetic hail damage from functional damage on this steel shingle roof? What inspection steps would you document?
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Dents alone are not a reason to replace a steel shingle roof; the key question is whether the coating and seams remain functional. Inspect the south slope in a grid, noting depth, location, and whether dents cross a seam, lap, or fastener. Check for cracked or missing paint, exposed steel, rust staining, and deformed slots or pans. A dent that only compresses the flat pan with intact coating is likely cosmetic; a dent that opens a lap, distorts a slot, or removes coating exposes metal to corrosion and can be functional damage. The rust at the vent and backed-out fasteners are separate issues. Use a moisture meter on the deck and a visual inspection in the attic. If the insurer will not authorize full replacement, obtain a written opinion from a qualified roof consultant and document the functional damage. Do not let the contractor caulk over rust or dents as a substitute for repair.
2. Evaluate the contractor’s proposed repair of the backed-out fasteners and vent boot. What should be done instead?
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The proposed repair is inadequate. Caulking backed-out fasteners does not restore the fastener’s withdrawal resistance or correct the cause, which is likely thermal movement or overdriving. Remove the affected fasteners, inspect the slots, and replace any panel with elongated or torn slots. Use the manufacturer-specified fastener type, length, and placement; do not use larger washers to clamp the panel. If 24 fasteners have backed out along one rake, inspect the entire rake and the adjacent field for a pattern. The vent boot should be replaced, not reused with a larger caulk collar. Install a new boot compatible with the metal roof, with a metal-to-rubber transition and proper lap under the shingle above and over the shingle below; seal only as a secondary measure. Check the deck around the vent for water damage. A permit and inspection may be required for the repair, and the manufacturer’s warranty may be affected if the repair does not follow published instructions.
3. The owner wants full replacement and the insurer wants a 20-panel repair. What code, warranty, and documentation factors should guide the final recommendation?
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Full replacement is not automatically justified by 5,000 sq ft of dents and 20 damaged panels. The decision should be based on functional loss, widespread fastener distress, corrosion, and the condition of the underlayment. If the repair is limited to 20 panels and a vent boot, the contractor must document that the remaining panels have intact coating, sound seams, and fasteners that are not backed out or elongated. If elongated slots or backed-out fasteners are widespread, the roof has a systemic installation or movement problem, and partial repair may fail again. Check whether the existing panels can be matched; if not, replacement of a larger area may be needed for appearance, but that is not a code requirement. Confirm permit requirements for roof repair or replacement and whether the manufacturer’s warranty requires a certified installer. Provide the owner with a written scope, photos, and a statement that the repair meets the manufacturer’s instructions; do not promise warranty coverage that the manufacturer has not confirmed.