What a 5/12 pitch means
A 5/12 roof rises 5 inches for every 12 inches it runs horizontally, which is an angle of 22.62° from level and a 41.7% slope. It is a conventional roof, walkable without roof jacks.
Roofing for a 5/12 roof
Suits almost every roofing: asphalt shingles, metal, wood shakes, clay or concrete tile.
Rise and rafter length at 5/12
For a gable roof, the run is half the building width. Rafter lengths are before the ridge deduction and overhang.
| Run | Building width | Rise | Rafter length |
|---|---|---|---|
| 4 ft | 8 ft | 1' 8" | 4' 4" |
| 6 ft | 12 ft | 2' 6" | 6' 6" |
| 8 ft | 16 ft | 3' 4" | 8' 8" |
| 10 ft | 20 ft | 4' 2" | 10' 10" |
| 12 ft | 24 ft | 5' | 13' |
| 14 ft | 28 ft | 5' 10" | 15' 2" |
| 16 ft | 32 ft | 6' 8" | 17' 4" |
| 20 ft | 40 ft | 8' 4" | 21' 8" |
Roof area at 5/12
Multiply the building footprint (including the overhangs) by 1.083 to get the roof surface. A 30 × 40 ft footprint has 1300 sq ft of roof at 5/12 — about 41 sheets of 4 × 8 sheathing before waste.