New Construction Metal Roof Installed Over Purlins

Place corner pieces where panels will meet bends at the edge of the roofing.

New construction metal roof installed over purlins.

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. Metal roof purlins are installed horizontally under metal roofs. The spacing of your purlins depends on the expected snow and wind load. The topic we want to discuss today is the purlin installation.

A standard retrofit sub framing system will not allow a positive attachment to the existing roof purlins. Use 1 1 4 inch nails to cover the outline of the roof with strips of metal eave flashing also called edging. Its use on residential projects is far less common but has been done a lot especially in rural areas. Measuring the outer perimeter existing profile of the roof panel skylight locations and modularity with the new metal roof rib spacing and identifying.

The actual installation of metal roofs on 1x or 2x purlins has been done for decades on ag and wood framed commerical buildings. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes. Purlins are 2 by 4 feet and are installed much like metal roofing. They give added support to the roof and also provide a nailing surface for the end panels and drip edge.

If there are gutters installed on the eaves the eave flashing should be installed to overhang the lip of the gutter by about 1 2 inch. They re also simple to install. 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. Installing a metal roof is a complicated process with many details.