Metal Roof Installed Over Purlins

Doesn t provide the flattest surface for the metal roofing to be installed over each course of shingles is about a 1 8 higher than the course just below it.

Metal roof installed over purlins.

It helps direct water away from the meeting points and keeps the roofing dry. 3 install 1 4 purlins down over the shingles before installing the metal roof the third way to install a metal roof over shingles is by applying 1 4 purlins over the shingle roof. Purlins are 2 by 4 feet and are installed much like metal roofing. 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.

I was driving by a new building being constructed and it has wood trusses with 2x4 horizontal purlins looks to be about 2 oc spacing on the trusses. 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 flashing should overlap the edge of the roof by one inch to help direct water. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

I have been playing around with the ribbed metal roof but pricing is pretty high over shingles obviously. Choosing to install a metal roof this way can save you some dough and garner all of the benefits of a metal roof in the humid climate of florida. Flashing is metal trim that fits over joints where two sections of roof meet. A metal roof can be installed over a shingle roof but you ll need to make sure the plywood under your shingle roof is in good enough shape to handle a new metal roof over top.

Bend the flashing into a v shape to fit over the top roof ridge and the corners where the panels meet. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. Metal roof purlins are installed horizontally under metal roofs. They give added support to the roof and also provide a nailing surface for the end panels and drip edge.

They then installed the metal directly to that.