Roof Pitch guide
Roof Pitch: Material Planning Guide
A roof pitch calculation produces a net geometric or quantity result, not a complete purchase order. Use the slope factor to connect pitch with roof area and rafter length. Stock availability, cut sequence, fastening, finish build-up, waste, and whole-unit purchasing are recorded as separate decisions after the calculation is checked.
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Roof pitch describes a triangle and may be expressed as rise over run, angle, percentage, or slope factor. The job record must identify which representation was measured because a normalized pitch ratio is not the same input as the full horizontal distance across a roof plan.
The purchasing pass starts from the unchanged net result, then records available stock lengths, sheet orientation, package quantities, offcut reuse, breakage, field trimming, and spare material as separate adjustments. This preserves the difference between what the geometry requires and what the supplier must deliver.
- Use the slope factor to connect pitch with roof area and rafter length. Keep the net result unchanged for review.
- List stock size, package size, waste, and spare material on separate lines.
- Round purchase quantities only after the available product is confirmed.
For this tool, the calculation method is angle = arctan(rise ÷ run). The consolidated page keeps this topic beside the worked method, material checks, source boundary, and printable record.
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