Installing Metal Roof On Purlins

Set the second.

Installing metal roof on purlins. Purlins are dimensional lumber that are fastened to the top chord of trusses connecting them together for bracing purposes. One of the first things to ensure a successful metal roof installation is to measure the roof length and slope correctly and precisely. Installation of pole barn purlins. Each panel should be cut to the exact size or there could be imprecise cuts and rough edges exposed to the elements leading to rust and roof coating failure.

The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. As long as the plywood under the shingle roof is in good condition this way can provide many benefits. Snap a chalk line horizontally across the roof two feet down from the top. 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.

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. This is by far the most common way to install a metal roof. Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. Be sure the larger edge is laid so that the small edge of the next panel will overlap it.

Run a tape measure from end to end along the rafters of the roof to determine how many purlins will be needed. 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. How to install metal roof purlins step 1. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed.

Lay the first purlin at the ridge of.