How do you put on a metal roof?
Short answer. A metal roof goes on in this order: tear off or prepare the old roof, repair the deck, install high temperature underlayment, set eave trim, then install panels square to the eave with the specified screws or clips, followed by flashing, closures and ridge cap. Getting the first panel square and the trim laps right decides whether the roof stays dry for decades.
Preparation
- Order panels cut to length, ideally one piece from eave to ridge so there are no end laps.
- Check the roof for square by measuring diagonals. An out-of-square roof needs the first panel set to the eave, with the difference absorbed at the rake trim.
- Underlayment rated for metal, since panels get hotter than shingles and ordinary peel and stick can soften.
Installation sequence
- Eave trim, then valley flashing, before any panels.
- First panel square to the eave, starting at the end the manufacturer recommends for side lap direction.
- Exposed fastener panels: screws with sealing washers in the flat or on the rib as the manufacturer specifies, in the pattern for your wind zone.
- Standing seam: hidden clips at engineered spacing, with seams snapped or mechanically seamed closed.
- Penetrations with flexible pipe flashings made for metal, and custom flashing at chimneys.
- Rake trim, sidewall and headwall flashing, then closures and ridge cap.
Mistakes that shorten its life
- Cutting with an abrasive saw, which scatters hot filings that burn the paint and rust.
- Leaving drill shavings on the panels, which leave rust spots within weeks in Georgia humidity.
- Overdriven screws that crush washers, and screws that miss the framing.
- Using caulk in place of proper flashing.
Metal is less forgiving than shingles, so installer experience matters. Check permits and HOA rules first. See metal roofing in Georgia and roof flashing explained.