How To Install Roof Underlayment

The standard approach for two ply roofing underlayment is to lap a 36 inch roll by 19 inches.

How to install roof underlayment.

Step 2 preparing the roof. Overhang the roof rake edge 1 5 and cover the underlayment with a metal rake edge trim. Minimum overlap guidelines are set by the. 4 lay the membrane on the roof with the plastic.

Measure the underlayment to the length of the roof plus the 4 inches of excess and cut the membrane straight across with a utility knife or shears. Be cognizant of the. Install drip edge at the roof eave edges. How to install roofing underlayment.

In roof areas where roof planes meet to form valleys which naturally channel high water flow in wet weather and other roof penetrations such as skylights plumbing vents roof to wall intersections are also important roof areas that can benefit from peel and stick membrane underlayment installation. Step 5. Peel the release liner from the membrane. Step 4 rolling the underlayment.

This provides two plies across the entire roof with three plies at the headlap. Step 1 safety. Step 3 preparing the underlayment. Synthetic roofing underlayment is to be laid horizontally parallel to eave with printed anti slip side up starting at the bottom of the lowest roof eave with a 1 5 underlayment overhang at the eave covering the pre installed eave drip edge.

Apply drip edge to the eave. Put on your protective eye wear and work boots before you begin. Press the membrane of the self adhering roofing underlayment in place with. The lap is half the width of the roll plus one extra inch for headlap.

Tack it in place at the corner with the end flush with the end of the roof and the bottom edge of the roll right along the bottom of the roof. Peel back 1 to 2 feet of release liner align membrane. Use a chalkline or align it by eye to make sure it is straight then drive roofing nails every foot or so to fasten it to the sheathing. Be careful moving up and down the ladder.