Purlin Spacing For Metal Roof

Purlin spacing is dependent on profile of the metal and gauge plus snow and wind load plus what the rafters are designed to carry.

Purlin spacing for metal roof.

An engineer will use a load chart in order to determine the spacing between metal purlins. If the space between posts is greater than 8 feet then brace is needed to avoid buckling. Purlin spacing for metal roofing. The spacing of purlins on roofs and girts on wall is usually 4 to 6 ft.

Purlins are 2 by 4 feet and are installed much like metal roofing. Doubling up in the valleys refer to the installation manual for the proper on center spacing and be sure that the. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. Metal roof purlins are installed horizontally under metal roofs.

Purlins need to follow the sides edges of the roof it is important to note that in addition to the. Once the purlin spacing is determined then the metal roofing panels are typically attached to every line of purlins. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. They give added support to the roof and also provide a nailing surface for the end panels and drip edge.

For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap. Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. By the standard the most used placement of purlin span for metal roof is five foot intervals. Load tables specifying safe loads for different spans are available from metal deck manufacturers.

In some cases however the exact spacing of the rafters doesn t matter if the roof has other means of supporting the metal panels. Numbers 20 and 22 u s. For 2x4s purlins the posts are spaced in 4 feet distance. 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.

The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. Without a set of blueprints with a pe s seal you have no option but to follow the inspectors gig. Standard gage are generally used for roofing. For 2x6s purlins the posts are spaced in 6 feet distance.

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. This will depend upon the type of panel that is used and the thickness of the steel.