Purlin Spacing For Metal Roof

Load tables specifying safe loads for different spans are available from metal deck manufacturers.

Purlin spacing for metal roof.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. For 2x4s purlins the posts are spaced in 4 feet distance. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap. Panel basics corrugated metal panels often called tin because in the past such panels were sometimes made of tin are typically steel or aluminum sheets that are used as a roofing material.

Standard gage are generally used for roofing. Numbers 20 and 22 u s. Purlin spacing for metal roofing. Doubling up in the valleys refer to the installation manual for the proper on center spacing and be sure that the.

Purlins are 2 by 4 feet and are installed much like metal roofing. Purlins need to follow the sides edges of the roof it is important to note that in addition to the. The spacing of purlins on roofs and girts on wall is usually 4 to 6 ft. Fyi we run purlins on 3 5 feet on center depending on size of purlin.

Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. In some cases however the exact spacing of the rafters doesn t matter if the roof has other means of supporting the metal panels. Without a set of blueprints with a pe s seal you have no option but to follow the inspectors gig. What do i need to know about installing purlins for my metal roofing project.

The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. 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. For 2x6s purlins the posts are spaced in 6 feet distance.

Metal roof purlins are installed horizontally under metal roofs. The typical roof structure now consists of steel i beam rafters placed approximately 10 feet this varies depending on purlin size and other variables apart with either 4 6 or 8 lightweight steel purlins installed horizontally across the rafters. By the standard the most used placement of purlin span for metal roof is five foot intervals. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

This will depend upon the type of panel that is used and the thickness of the steel. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. The typical spacing standards for residential and commercial buildings are about 1 to 2 foot.