Spacing Of Purlins For A Metal Roof

Correctly measure the spacing of furring strips for a metal roof to further decrease condensation.

Spacing of purlins for a metal roof.

Rafter spacing is based on the width of the metal roofing panels. The width of metal panels will determine the rafter spacing. 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. Screw line spacing for metal roofing over metal purlins.

Once the purlin spacing is determined then the metal roofing panels are typically attached to every line of purlins. An engineer will use a load chart in order to determine the spacing between metal purlins. The heavier the expected load is the shorter the distance between the purlins. On a standard load most designs call for purlin placement at five foot intervals.

Purlins are 2 by 4 feet and are installed much like metal roofing. Wider panels allow for greater spacing between rafters. A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel. This will depend upon the type of panel that is used and the thickness of the steel.

There are three typical methods used to fasten purlins to the top chord of trusses. Twenty four inches is a common spacing of furring strips for a metal roof. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. However engineering determines the optimal spacing between the purlins.

The eave purlin marks the first purlin at the wall connection. 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. Metal roof purlins are installed horizontally under metal roofs. There is a chance of damaging roofing sheets if you are failed to do so.

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. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. We do recommend it however. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

Rhino metal building. Do all roofing projects require purlins. 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.