What is the metal roof installation process on a house?
Short answer. A residential metal roof goes on in a set order: measure and order panels, remove the old roof or prepare it for an approved overlay, repair the deck, install heat-rated underlayment, set eave, rake and valley trim, run the panels with the correct screws or clips, flash walls, chimneys and pipes, then close the ridge and hips. Standing seam takes longer than exposed-fastener panels because its panels are held by hidden clips and the seams are locked together.
The steps
- Measure and order. Panels are ordered or roll-formed to exact lengths for each slope, so careful measurements come first.
- Tear-off and deck repair. Most homes go back to the deck. Some panel systems allow installation over one layer of shingles, but a tear-off lets the deck be checked and repaired.
- Underlayment. A synthetic or self-adhered underlayment rated for the heat that builds up under metal, with extra leak barrier in valleys and at penetrations.
- Edge trim and valleys. Eave trim and valley metal go on before the panels so the panels lap over them; rake trim usually follows the panels.
- Panels. Set square to the eave and worked across the roof. Exposed-fastener panels are screwed through the face into the deck or purlins; standing seam panels are held by concealed clips and the seams are snapped or mechanically seamed.
- Flashing. Sidewall and headwall flashing, chimney flashing and pipe boots made for metal.
- Ridge and hips. Closures seal the panel ribs, then the ridge cap goes on, often vented.
- Cleanup. Metal shavings from cutting are swept off right away, because they rust and stain the finish.
How long it takes
Exposed-fastener panels on a simple house go quickly; standing seam on a cut-up roof can take several days, longer than a shingle roof of the same size. Panel lead times and weather affect the schedule more than they do with shingles.
What to check in a bid
Panel type and gauge, fastener or clip system, underlayment type, trim profiles, and whether the installer follows the panel maker's details at valleys and walls. More in metal roofing in Georgia and synthetic underlayment vs felt.