New Construction Metal Roof Installed Over Purlins

The spacing of your purlins depends on the expected snow and wind load.

New construction metal roof installed over purlins.

The actual installation of metal roofs on 1x or 2x purlins has been done for decades on ag and wood framed commerical buildings. 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. Our metal roof and wall panels qualify for underwriters laboratories ul class a fire rating ul 90 wind uplift rating and class 4 ul impact resistance hail rating. For the convenience of your customers we provide installation guides and metal roofing installation how to videos to support their building projects.

Measuring the outer perimeter existing profile of the roof panel skylight locations and modularity with the new metal roof rib spacing and identifying. Use 1 1 4 inch nails to cover the outline of the roof with strips of metal eave flashing also called edging. Installing a metal roof is a complicated process with many details. 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.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. They re also simple to install. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

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. Its use on residential projects is far less common but has been done a lot especially in rural areas. 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.