Spacing For Purlins Forfiber Glass Roof Panels

Next pre drill holes on the end and side ridges of the panels spacing the holes 6 to 8 inches apart.

Spacing for purlins forfiber glass roof panels.

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 width of metal panels will determine the rafter spacing. Without a set of blueprints with a pe s seal you have no option but to follow the inspectors gig. This will depend upon the type of panel that is used and the thickness of the steel.

While panels may not fail under heavy snow loads strain at fastening points can cause slight cracking. In heavy snow areas 500 series or greater panels are recommended and closer spacing of purlins should be considered. Purlin spacing is dependent on profile of the metal and gauge plus snow and wind load plus what the rafters are designed to carry. 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. When looking at the ends of the rails the purlins shapes look like the letter c or the letter z the eave purlin marks the first purlin at the wall connection. The metal roof purlins spacing must be done correctly within narrow tolerances. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

However engineering determines the optimal spacing between the purlins. There is a chance of damaging roofing sheets if you are failed to do so. There are countless old corrugated roofs out there with 2 5 2 67 2 75 and 4 25 rib spacing as well as other ribbed type panels such as the 7 2 industrial rib roof panel. These roofs are commonly problematic because the rib spacing is typically inconsistent thus not permitting a standard factory notched hugger sub purlin to be used.

To determine how far apart to set rafters measure the width of the metal panel and then the width of the first hill and valley of the panel. On a standard load most designs call for purlin placement at five foot intervals. To install corrugated roofing start by cutting your panels to length with an angle grinder. Fyi we run purlins on 3 5 feet on center depending on size of purlin.

Table is based on section properties or actual load tests available upon request. Wider panels allow for greater spacing between rafters. The wider the roofing panels the greater spacing distance you should put. Beginning at the outside edge of your roof place each panel directly onto the purlins that are attached to the roof trusses.