Metal is ordered by panel, not just by square
Shingles can be ordered from total area. Metal panels are usually cut to length, so each plane needs its own panel length and panel count. Area is still useful for pricing and comparing bids.
Measure along the slope for panel length. If you only have a horizontal run, multiply it by the pitch factor: for example, 14 ft of horizontal run at 6:12 is about 14 × 1.118 ≈ 15.7 ft of panel run before overhang.
Count panels by coverage width
Divide the plane width measured along the eave by the panel’s stated coverage width (not its overall width) and round up. Example: a 42 ft eave with 36-inch coverage panels needs 42 ÷ 3 = 14 panels.
Hip and valley planes are triangular or trapezoidal, so panel lengths vary across the plane and offcuts are less reusable. Lay these out panel by panel or let the supplier do the takeoff from your measurements.
Trim follows the edges
Eave trim and rake (gable) trim follow eaves and rakes. Ridge cap covers ridges and hips. Valley flashing follows valleys. Sidewall and endwall flashing follow wall-to-roof joints.
Trim comes in fixed lengths with required overlaps, so add laps when converting linear feet to pieces. Your supplier’s profile details govern the final count.
Check pitch limits and verify
Exposed-fastener and standing-seam panels have different minimum pitch requirements. Check each plane’s pitch against the manufacturer’s published minimum, especially low-slope porches.
Field-verify lengths before panels are cut. A satellite report is a good planning measurement, but cut-to-length orders should be checked on site.
How much overhang for a metal roof?
Overhang is set by the panel manufacturer’s eave detail, not by a universal rule. For example, ABC Metal Roofing’s installation guidance for exposed-fastener panels calls for overhanging the eave by one and a half to two inches at most. Hidden-fastener and standing-seam panels often hem or lock onto an eave cleat instead, which changes the length.
When you calculate panel length, add the overhang your panel’s installation manual specifies to the sloped run, and include any gutter or eave-trim detail. Check the manual for the exact panel profile you are ordering before panels are cut.
Sources & further reading
Product details reflect FastRoofReport’s current measurement and report workflow. Geometry examples are rounded illustrations, not measurements of the pictured property.