What a 14/12 pitch means
A 14/12 roof rises 14 inches for every 12 inches it runs horizontally, which is an angle of 49.4° from level and a 116.7% slope. It is a steep roof, too steep to walk safely without roof jacks or a harness.
Roofing for a 14/12 roof
Suits shingles, metal, slate and tile. Steep enough that roofers need roof jacks or harnesses, which adds to labour cost.
Rise and rafter length at 14/12
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 | 4' 8" | 6' 1 3/4" |
| 6 ft | 12 ft | 7' | 9' 2 5/8" |
| 8 ft | 16 ft | 9' 4" | 12' 3 1/2" |
| 10 ft | 20 ft | 11' 8" | 15' 4 3/8" |
| 12 ft | 24 ft | 14' | 18' 5 1/4" |
| 14 ft | 28 ft | 16' 4" | 21' 6 1/8" |
| 16 ft | 32 ft | 18' 8" | 24' 7" |
| 20 ft | 40 ft | 23' 4" | 30' 8 13/16" |
Roof area at 14/12
Multiply the building footprint (including the overhangs) by 1.537 to get the roof surface. A 30 × 40 ft footprint has 1844 sq ft of roof at 14/12 — about 58 sheets of 4 × 8 sheathing before waste.