Purlin Spacing For Steel Roofing

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

Purlin spacing for steel roofing.

Dead load will be the actual weight of the roof steel and the roof purlins. Screw line spacing for metal roofing over metal purlins. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. 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. Do all roofing projects require purlins. If the space between posts is greater than 8 feet then brace is needed to avoid buckling. By the standard the most used placement of purlin span for metal roof is five foot intervals.

For 2x6s purlins the posts are spaced in 6 feet distance. We do recommend it however. Purlin spacing for metal roofing. For 2x4s purlins the posts are spaced in 4 feet distance.

However engineering determines the optimal spacing between the purlins. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. 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 cos of the purlin spacing is because the load on the purlins is vertical and the purlin spacing is with the run of the roof.

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. For sake of discussion we will assume a minimal roof snow load of 20 psf pounds per square foot and a 4 12 roof slope. Spacing for purlins on a standard load most designs call for purlin placement at five foot intervals.

Purlin spacing is dependent on profile of the metal and gauge plus snow and wind load plus what the rafters are designed to carry. Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.