How much metal roofing do I need for my roof?
Step 1: Measure each plane
For every roof plane, record the eave length and the slope length from eave to ridge. If you cannot measure the slope directly, measure the horizontal run and multiply by the pitch factor: about 1.12 for a 6 in 12 roof, 1.20 for 8 in 12, and 1.41 for 12 in 12.
Step 2: Count panels
Divide the eave length by the panel's coverage width and round up. Example: a 40-foot eave with 36-inch coverage panels needs 40 divided by 3, or 13.3, so 14 panels. Each is cut to the slope length plus the overhang into the gutter.
Step 3: Handle hips and valleys
Planes that end at a hip or valley need panels cut on an angle, and the offcuts are often too short to reuse. Add waste accordingly; simple gable roofs waste little, cut-up roofs waste more.
Step 4: List the trim
- Eave trim along every eave.
- Rake or gable trim along sloped edges.
- Ridge and hip caps.
- Valley flashing.
- Sidewall and endwall flashing where roofs meet walls.
Trim comes in fixed lengths, usually around 10 feet, with overlaps.
Step 5: Accessories
Closures, fasteners or clips, sealant, pipe flashings and underlayment by the square.
Panels are custom cut, so a measuring mistake means reordering. Verify on site before ordering. See how roofers measure a roof and metal roofing in Georgia.