Installing A Metal Roof Over Purlins

Lay the first purlin at the ridge of.

Installing a metal roof over purlins.

How to install metal roof purlins step 1. The most common method employed is laying the purlin flat typically a 2 4 and nailing to the truss with two 20d galvanized ring shank nails. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. It should overlap the edge of the gutter if you have them.

Snap a chalk line horizontally across the roof two feet down from the top. In this installation the vapor barrier is installed on the side of the insulation nearest the interior of the building. As long as the plywood under the shingle roof is in good condition this way can provide many benefits. Lay the starter row of metal shingles at the drip edge and affix to the roof with metal roofing nails.

This is by far the most common way to install a metal roof. The edging or eave flashing consists of metal strips that are used to cover the perimeter of the roof. The topic we want to discuss today is the purlin installation. 3 install 1x4 purlins down over the shingles before installing the metal roof the third way to install a metal roof over shingles is by applying 1x4 purlins over the shingle roof.

Run a tape measure from end to end along the rafters of the roof to determine how many purlins will be needed. Most metal shingles will be attached to the roof using metal shingle. When using plywood nail it directly to the purlins and screw the metal roofing panels through the plywood into the purlins as instructed by the manufacturer. This method is used for trusses designed to be closer together from 2 on center up to a maximum of 5 on center.

Work up from the initial row starting at the lower corner in a diagonal pattern staggering the shingles to prevent gaps. Purlins are non pressure treated 1 x 4 x 12 lumber that is installed on to the roof in a specific layout pattern and screw pattern.