Felt underlayment on tile roofs with a pitch of 4:12 or greater should have a minimum _____-inch headlap?

Felt underlayment on tile roofs with a pitch of 4:12 or greater requires a minimum headlap of 2 inches to ensure proper water shedding and to minimize the risk of water infiltration. Headlap is the vertical distance that one layer of roofing material overlaps the layer below it, which is crucial in directing water away from the seams of the roof and preventing leaks.

In roofing, especially with a steeper pitch, adequate headlap helps ensure that rainwater drains away rather than seeping underneath the roofing material. The 2-inch headlap is a standard practice that balances effective water management while maintaining installation efficiency. This specification is based on industry standards and guidelines designed to enhance the longevity and performance of the roofing system.