Spacing Of Purlins For A Metal Roof

A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel.

Spacing of purlins for a metal roof.

However the screw placement diagrams commonly are based on the on center spacing center to center of the purlin rather than the gap between purlins to determine the length and spacing of the screws needed to prevent wind blowoff for various design wind speeds so pay close attention to that difference. This will depend upon the type of panel that is used and the thickness of the steel. 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 purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

The metal roof purlins spacing must be done correctly within narrow tolerances. Wider panels allow for greater spacing between rafters. Do all roofing projects require purlins. Screw line spacing for metal roofing over metal purlins.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. On a standard load most designs call for purlin placement at five foot intervals. However engineering determines the optimal spacing between the purlins. There are three typical methods used to fasten purlins to the top chord of trusses.

The width of metal panels will determine the rafter spacing. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. Purlins are 2 by 4 feet and are installed much like metal roofing. Correctly measure the spacing of furring strips for a metal roof to further decrease condensation.

The building was built 24 on center. The eave purlin marks the first purlin at the wall connection. Twenty four inches is a common spacing of furring strips for a metal roof. In the order shown above purlins laying flat use 2 20d ring shank nails per connection for trusses with minimal spacing hung purlins for wide span trusses lu26 hangers for 2 6 lu28 hangers for 2 8 etc and purlins on edge overlapped.

There is a chance of damaging roofing sheets if you are failed to do so. Once the purlin spacing is determined then the metal roofing panels are typically attached to every line of purlins. Purlin spacing for metal roofing the country inspector upon approving the plans seems to have written in per manufacturers specs regarding 2x4 purlins on 16 centers. Metal roof purlins are installed horizontally under metal roofs.

The wider the roofing panels the greater spacing distance you should put. An engineer will use a load chart in order to determine the spacing between metal purlins. Rafter spacing is based on the width of the metal roofing panels.