Gambrel Roof Metal Roofing Calculator: Panels and Cost Estimate
Panel count, linear feet, weight, and cost range for standing seam and corrugated metal roofs.
Standing Seam vs Corrugated
Standing seam panels lock together with raised vertical seams and hidden clip fasteners. No screws penetrate the panel face. Corrugated panels lap horizontally and are fastened through the face with exposed gasketed screws. The first lasts 50+ years; the second leaks at every screw within 20 if the gaskets dry out. On a residential gambrel, use standing seam. On an open hay barn, corrugated is fine.
Knuckle Flashing Detail
The gambrel knuckle is the most demanding flashing detail on the roof. Water and ice from the upper slope concentrate at the pitch transition. The right detail is a continuous pre-formed pan flashing that hems over both the upper and lower panels and is back-caulked with butyl tape. Add a 36-inch wide strip of self-adhering ice-and-water shield under the flashing as the second line of defense.
Cost per Square Foot by Type
| Material | Installed $/ft² | Lifespan | Notes |
|---|---|---|---|
| Corrugated steel | $4–$8 | 20–35 yr | Agricultural buildings |
| Standing seam steel | $9–$14 | 40–60 yr | Residential gambrel |
| Standing seam aluminum | $11–$16 | 50+ yr | Coastal, no rust |
| Galvalume | $8–$13 | 60 yr | Hot climates |
| Copper | $20–$40 | 100+ yr | Architectural |
These figures are installed price per square foot. For a materials-only estimate that adds rafter lumber and sheathing to the roofing line, use the roof cost calculator.