Metal Roof Installed Over Purlins

As long as the plywood under the shingle roof is in good condition this way can provide many benefits.

Metal roof installed over purlins.

Do all roofing projects require purlins. This is by far the most common way to install a metal roof. 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. Work at a comfortable steady pace trying not to rip up or carry off too much old roofing at once.

Although you can install corrugated metal roofing over shingles for the best foundation it is recommended that all the old roofing be removed. Purlins are 2 by 4 feet and are installed much like metal roofing. Metal roof purlins are installed horizontally under metal roofs. We do recommend it however.

The spacing of your purlins depends on the expected snow and wind load. 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. The topic we want to discuss today is the purlin installation. 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.

Place corner pieces where panels will meet bends at the edge of the roofing. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. Use 1 1 4 inch nails to cover the outline of the roof with strips of metal eave flashing also called edging. 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.

The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.