Metal roofing, explained without the sales pitch

Hail, dents and your insurance policy

Before you choose metal, find out how your policy handles cosmetic damage. Missouri’s Department of Commerce and Insurance publishes roof coverage summaries by insurer, and some show an exclusion for cosmetic loss to a metal roof, meaning damage limited to how the surface looks, or a discount tied to accepting that exclusion.

Under that kind of wording, dents that do not let water in may not be paid. Ask your agent before you buy, not after the next storm.

Switching materials can change the paperwork

Changing what your roof is made of can trigger a permit where a like-for-like re-roof would not. St. Peters, for example, requires a re-roof permit whenever the roof covering changes to a different material. Your building department can confirm the current rule for your address.

Details worth asking about

These come from DOE’s Building America Solution Center guide to metal roofs. Ask any roofer you interview how their bid handles each one.

• Matching metals: the guide says not to mix metals on the roof, and to use screws and accessories that match or are chemically compatible with the panels.
• Fasteners driven right: screws go in straight, with the rubber washer sealing against the panel without being crushed.
• Valleys: flashing of the same corrosion-resistant metal as the roof, extending at least 8 inches from the center.
• What goes underneath: for a sealed roof deck, the guide lists a self-adhered membrane over the whole deck, taped sheathing seams under heavy felt or synthetic underlayment, or two layers of #30 felt.