Roofing Felt Overlap Size

Roll out the felt no more than midway perhaps 25 feet or so across the average size roof.

Roofing felt overlap size.

The spacing between the nails on the drip edge should be less than 12 inches apart. However you must allow for overlaps on joints. Therefore a 2 inch overlap provides redundancy at the edges where the barrier is weakest. You can see the difference between the underlayment overlapped 19 inches on the roof to the right and overlapped 2 inches on the roof to the left.

Purchase enough felt to cover your roof s area. One roll of conventional 15 felt covers 432 square feet 40 1 m 2. Never walk on felt that has not been nailed down. The drip edge should extend at least 2 inches on the roof.

Pick up the roll with both hands. In most cases this will leave 400 square feet 37 m 2 of net coverage per 1 roll. Overlap the end of a roll about 4 inches with the start of a new roll and fasten both pieces to the. If there is any wind at all roll out the felt only about 10 feet.

Convert the area from inches to feet prior to purchasing your felt. In steep slope roofs 4 12 and steeper the upper courses of felt underlayment should overlap lower courses by at least 2 inches. Roofing requirements roofing felt is required to overlap 2 inches over the lower felt course. Continue along the roof to the other end and trim the felt flush at the end with a utility knife.