Roofing Underlayment Calculator
Jump to calculatorEstimate felt or synthetic underlayment rolls for roof areas with single or double layers. Add waste for overlaps, valleys, and starter courses when planning orders.
Inputs
Tip: Many installs use double coverage at eaves or in valleys. Add extra waste for complex roof geometry.
Results
Rolls needed
6
Adjusted coverage: 2,200 sq ft
Assumptions
- Coverage varies by overlaps, fastener rows, and starter courses.
- Waste factor accounts for offcuts, valleys, and detailing.
- Roll coverage assumes full usable area; check product specs.
Next Steps
- ✓ Verify roof area with the roofing squares calculator
- ✓ Review best practices in the roofing calculators guide
Example
A 2000 sq ft roof with 1 layer(s) and 10% waste needs about 6 rolls of underlayment using the selected coverage.
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Start with our comprehensive Roofing Calculator Guide to understand roofing squares, bundles, pitch multipliers, and material estimates before ordering.