MONO-PITCH & LEAN-TO DESIGN
Shed Roof Pitch Guide: Slopes, Rise Calculations & Materials
A shed roof (also known as a mono-pitch, skillion, or lean-to roof) slopes in a single direction from a high wall to a low wall. Selecting the optimal shed roof pitch requires balancing headroom, rainwater drainage, snow load shedding, and roofing material minimum slopes (from 1/4:12 for membranes to 3:12 for metal panels and 4:12 for shingles).
Quick Sizing Rule for an 8-Foot Shed
For a standard 8-foot wide shed (8-foot horizontal run):
- 3/12 Pitch (Corrugated Metal / Low Shingle): Requires a 24-inch vertical rise ($2text{ ft}$ height difference between front and rear walls).
- 4/12 Pitch (Standard Shingles): Requires a 32-inch vertical rise ($2text{ ft } 8text{ in}$ height difference).
- 6/12 Pitch (Steep Snow Shedding): Requires a 48-inch vertical rise ($4text{ ft}$ height difference).
Total Elevation Rise Table by Shed Width (Span)
| Shed Horizontal Run (Width) | 2/12 Pitch Rise | 3/12 Pitch Rise | 4/12 Pitch Rise | 6/12 Pitch Rise |
|---|---|---|---|---|
| 8 Feet | 16 inches (1.33 ft) | 24 inches (2.00 ft) | 32 inches (2.67 ft) | 48 inches (4.00 ft) |
| 10 Feet | 20 inches (1.67 ft) | 30 inches (2.50 ft) | 40 inches (3.33 ft) | 60 inches (5.00 ft) |
| 12 Feet | 24 inches (2.00 ft) | 36 inches (3.00 ft) | 48 inches (4.00 ft) | 72 inches (6.00 ft) |
| 16 Feet | 32 inches (2.67 ft) | 48 inches (4.00 ft) | 64 inches (5.33 ft) | 96 inches (8.00 ft) |
Selecting the Right Roofing Material for a Shed Roof
- Under 2/12 Pitch ($<9.46^circ$): Shingles are prohibited by building code. Use single-ply TPO, EPDM rubber membrane, or self-adhered roll roofing with positive slope ($1/4:12$ minimum).
- 2/12 to 3/12 Pitch ($9.46^circ$ to $14.04^circ$): Compatible with standing seam metal or asphalt shingles installed with a continuous double underlayment / ice & water barrier (IRC §R905.2.2).
- 3/12 Pitch and Higher ($ge 14.04^circ$): Fully compatible with exposed-fastener corrugated metal panels, R-panels, and standard asphalt shingles.
Related Shed Tools & Guides
Calculate exact rafter slope lengths with our Shed Roof Calculator, explore slopes on our Roof Pitch Chart, or check code limits in our Minimum Roof Pitch Guide.