Metal Roof Over Purlins

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

Metal roof over purlins.

Do all roofing projects require purlins. You also could install a corrugated through fastened metal roofing product and probably not have issues. The spacing of your purlins depends on the expected snow and wind load. Use 1 1 4 inch nails to cover the outline of the roof with strips of metal eave flashing also called edging.

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. Pay attention also to the fastening of the purlins to the roof structure if they are not fastened down well enough to carry the design uplift load the roof can come off purlins and all. 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. If your home s existing shingles are pretty curled you could install a textured metal roof such as a metal shingle shake or tile directly over the curled shingles along with underlayment.

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. And the purlins need to be fastened securely into the rafters trusses too and for some wind loadings the decking sheathing needs to be screwed down to the. Metal roof purlins are installed horizontally under metal roofs. Purlins are 2 by 4 feet and are installed much like metal roofing.