Roofing Shingle Calculator
🔧 Engineering Notes & Cheat Sheet
Roofing Measurement Standards
| Component | Coverage | Notes |
|---|---|---|
| 1 Square of Shingles | 100 sq ft | Industry standard measurement |
| 3-Tab Bundle | 33.33 sq ft | 3 bundles = 1 square |
| Architectural Bundle | 33.33 sq ft | Heavier weight, same coverage |
| Starter Course | +10% bundles | For eaves and rakes |
| Underlayment | 1 roll/4 squares | #15 felt or synthetic |
📐 Pitch Multiplier Reference
| Pitch (rise/12) | Multiplier | Roof Type |
|---|---|---|
| 1/12 - 3/12 | 1.03 - 1.05 | Low Slope |
| 4/12 - 6/12 | 1.05 - 1.12 | Conventional |
| 7/12 - 9/12 | 1.16 - 1.25 | Steep |
| 10/12 - 12/12 | 1.30 - 1.42 | Very Steep |
👷 Pro Tips from Roofing Contractors
#1 Always Order 10-15% Extra
Cutting waste, pattern matching, and future repairs require extras. Complex roofs with valleys/dormers need 15%.
#2 Check Local Building Codes
Florida/coastal areas require hurricane clips. Snow regions need ice/water shield at eaves. Verify underlayment requirements.
#3 Bundle Lot Consistency
Ensure all bundles are from same dye lot to avoid color variations. Store off ground on pallets.