Sheet set A · Architectural
Roofing
Squares, pitch, underlayment, ridge and valley.
Issued
2 of 2Roofing Calculator
Squares, shingle bundles, underlayment rolls, ridge cap and starter for up to four roof sections, from the plan footprint and the pitch, with every yield read off a named manufacturer sheet.
Open sheet → A-104Roof Pitch Calculator
One slope written four ways and solved back from any of them — rise in 12, angle in degrees, grade in percent and the slope factor — plus the ridge height and the common rafter length once a span is typed.
Open sheet →Quick reference
| Rise in 12 | Pitch factor | Sloped sq ft per 1,000 sq ft of plan | Squares |
|---|---|---|---|
| 3 | 1.0308 | 1,031 | 10.31 |
| 4 | 1.0541 | 1,054 | 10.54 |
| 6 | 1.118 | 1,118 | 11.18 |
| 8 | 1.2019 | 1,202 | 12.02 |
| 10 | 1.3017 | 1,302 | 13.02 |
| 12 | 1.4142 | 1,414 | 14.14 |
The factor is geometry, not a table anyone had to publish: the square root of the rise squared plus twelve squared, over twelve. Multiply the footprint you can measure on the ground by it and you have the surface the shingles have to cover. Every material figure on sheet A-102 is read off one named product sheet instead — GAF Timberline HDZ, GAF Seal-A-Ridge, GAF Pro-Start and GAF FeltBuster, 4 documents in all — and each one stays a field you overwrite with the figure printed on the wrapper you are buying. Waste has no default there, and neither do nails, flashing or price: nothing we opened publishes a quantity for them.