How To Install Roof Underlayment

Be careful moving up and down the ladder.

How to install roof underlayment.

Start the roof felt at one bottom corner of the roof. Overhang the roof rake edge 1 5 and cover the underlayment with a metal rake edge trim. The standard approach for two ply roofing underlayment is to lap a 36 inch roll by 19 inches. 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.

Step 1 safety. Put on your protective eye wear and work boots before you begin. How to install roofing underlayment. Apply drip edge to the eave.

Step 2 preparing the roof. Cut drip edge flashing at an angle at the corner press it lightly against the eave end not too hard or you will misshape it and drive a nail near the end. 4 lay the membrane on the roof with the plastic. 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.

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. The lap is half the width of the roll plus one extra inch for headlap. Minimum overlap guidelines are set by the. Peel the release liner from the membrane.

Back roll method cut the membrane into 10 to 15 foot lengths and re roll loosely. Be cognizant of the. Press the membrane of the self adhering roofing underlayment in place with. Step 5.

This provides two plies across the entire roof with three plies at the headlap. Peel back 1 to 2 feet of release liner align membrane. 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. Step 4 rolling the underlayment.