How to Measure a Roof
Updated
To measure a roof, find the footprint (length × width), multiply by a pitch factor to get the true surface area, then divide by 100 for roofing squares. Add 10–15% for waste. Shingles come three bundles per square.
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Why pitch matters
A roof's actual surface is larger than its footprint because of the slope. Multiply the footprint by a pitch factor — for example 1.118 for a common 6:12 roof — to get the real area.
Squares and bundles
- 1 square = 100 sq ft of roof
- 3 bundles of architectural shingles per square
- Add 10% waste for simple roofs, 15% for cut-up roofs