How To Attach Roof Underlayment Steel Roofing

We recommend a polypropylene scrim reinforced underlayment made up of multiple layers.

How to attach roof underlayment steel roofing.

It provides a solid flat surface to attach the new metal roof to. Fasten the field area in the middle of the roll a minimum of 24 o c. Nail down squarely 90 degrees into the deck to secure caps flush to the underlayment. The underlayment also known as roofer s felt is usually asphalt synthetic or polymer based.

Place it on the outside roof edge. Mark a chalk line 35 inches above the roof edge to align the underlayment. Make sure the product is designed to be used under metal. This type of underlayment is critical to a quality roof installation.

Before applying roofing you ll need to cover the sheathing with roofing felt also often called tar paper most local codes call for using 30 pound felt. This material separates the roofing from the substrate provides secondary weather protection and guides drainage down the side of the roof. Position the roll so that 2 inches of the underlayment are able to hang over outside roof edge decking. In normal wind zones the nails should be driven at 6 0 o c.

Fasten drip edge on eaves with galvanized nails and a hammer about 12 inches. Most metal shingles will be attached to the roof using metal shingle. Installing the metal roofing over 1x4 s allows the ability to also install additional insulation under the metal roof that can t be done the other two ways. Most metal roofs will also require underlayment as well as a slip sheet.

Here are the pros and cons to installing the metal roofing over 1x4 s. It serves as a moisture barrier as well as a slip sheet. Use your hammer and nails to secure the underlayment next to the outside roof edge. Work up from the initial row starting at the lower corner in a diagonal pattern staggering the shingles to prevent gaps.

Some roofers prefer to attach felt underlayment with 1 inch roofing nails or special nails with plastic washers but most codes allow staples which are easier to drive. Once again this is used on cold roof construction. On center on both head and end laps.