How Close Do You Install Perlins Under A Metal Roof

Install the roofing screws vertically along each rib in the panel.

How close do you install perlins under a metal roof. Do i need the plywood base. Applying right over the shingles will rub the back of the metal roof and eventually holes in the panels. If the roof has no roen decking and only one layer of roofing you can usually apply an insulating barrier 1 4 foam core insulation and just apply right over the existing roof. Twenty four inches is a common spacing of furring strips for a metal roof.

Correctly measure the spacing of furring strips for a metal roof to further decrease condensation. The easiest and by far the quickest way to install metal roof insulation is with 1 inch staples. You will also need to install purlins around penetrations such as plumbing pipes electrical pipes and skylights among others. Purlins are 2 by 4 feet and are installed much like metal roofing.

I have an existing steel roof presently just on purlins. Another benefit of using staples is that they do not make a large hole when penetrating into the sheathing. The washer under the screw head should seal to the surface of the panel without bulging or shifting. Purlins need to follow the sides edges of the roof it is important to note that in addition to the proper spacing and doubling of purlins the valleys it is essential to include purlins along the entire perimeter of the roof.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. When using plywood nail it directly to the purlins and screw the metal roofing panels through the plywood into the purlins as instructed by the manufacturer. He won t do it unless i put on plywood as a base he also recommended ice and water underlayment. It needs to be replaced due to leaks and one contractor the one i d really like to hire refuses to put the new metal roof on just purlins.

The common 4 on center design is suitable for snow loads up to 60 for most applications. In this installation the vapor barrier is installed on the side of the insulation nearest the interior of the building. You can easily go through several sheets of insulation and know that they are secure. Too high a snow load means the purlins fail regardless of how close together you put them because a 2 4 or 2 6 flat can only span a certain distance between trusses as snow loads increase.

Place the first screw about 7 inches from the bottom and each subsequent screw about 18 to 24 inches apart along the vertical run.