Installing Metal Roof On Purlins

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.

Installing metal roof on purlins.

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. Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. 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. 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. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. One of the first things to ensure a successful metal roof installation is to measure the roof length and slope correctly and precisely.

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. How to install metal roof purlins step 1. As long as the plywood under the shingle roof is in good condition this way can provide many benefits.

Purlins are dimensional lumber that are fastened to the top chord of trusses connecting them together for bracing purposes. Set the second. 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.

Lay the first purlin at the ridge of.