Roof pitch: rise in inches per 12 inches horizontal run. 6/12 means 6 inch rise per foot. 4/12 to 12/12 common for shingles. Minimum 4/12 for asphalt shingles, 3/12 with special underlayment. Steeper roofs have more surface area (use multiplier).
Quick Tips
- Always order 10-15% extra materials for waste
- Check local building codes before starting
- Measure twice, cut once — verify all inputs
Frequently Asked Questions
Rise in inches per 12 inches horizontal run. Example: 6/12 means 6 inch rise per foot.
4/12 pitch minimum for asphalt shingles. 3/12 acceptable with special underlayment.
Level 12 inches from roof surface, measure vertical distance from level to roof.