How To Install Underlayment For Metal Roofing

Press the membrane of the self adhering roofing underlayment in place with heavy hand pressure to ensure the desired adhesion to the roof deck.

How to install underlayment for metal roofing.

The lap is half the width of the roll plus one extra inch for headlap. Here is a video about roofing underlayment. Install the roofing screws vertically along each rib in the panel. Peel back 1 to 2 feet of release liner align membrane.

Underlayment must also act as a secondary weather barrier in case the roof fails. Peel the release liner from the membrane. Traditionally metal roofs have used standard 30 pound felt paper underlayment. Be sure the larger edge is laid so that the small edge of the next panel will overlap it.

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. Check this out. How to install roofing underlayment the proper way. However contractors now recognize the benefits of synthetic.

This provides two plies across the entire roof with three plies at the headlap. Align the first metal roofing panel so that it overlaps the edging by 1 2 to 3 4 of an inch and is square to the roof line. Subscribe and share please. Cut the membrane into 10 to 15 foot lengths and re roll loosely.

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. The quality and type of underlayments used on the project in the long term will affect the overall performance of the roof. 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.