How Far To Space Purlins Steel Roof

Measure the section of the roof from the fascia to the peak and divide this by two which is the two foot spacing of the wood nailers.

How far to space purlins steel roof. If the space between posts is greater than 8 feet then brace is needed to avoid buckling. 80 screws for each roofing square. In this example the section of roof is 20 feet wide and 14. Purlin spacing for metal roofing.

Here are two easy formulas for determining the amount of metal roofing screws. Lay the first purlin at the ridge. For 2x4s purlins the posts are spaced in 4 feet distance. Fyi we run purlins on 3 5 feet on center depending on size of purlin.

Without a set of blueprints with a pe s seal you have no option but to follow the inspectors gig. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. Edit answer for another 41 minute you need to check the installation instructions from the manufacturer depending on whether the purlins firring strips are 1x or 2x material and how wide thickness metal gage of roofing steel or aluminum type of seams design wind and snow loading whether designed to be walked on or not etc i have seen it vary from as little as 4 inches clear gap between firring strips on lightweight aluminum to as much as 4 feet on very heavy gage. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.

For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. Less expensive 1 3rd less board footage of lumber fewer pieces to handle fewer joist hangers to have to attach and only one half as many screws to attach the roof steel. The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load.

Take your square footage and multiply it by 80. Run a tape measure from end to end along the rafters of the roof to determine how many purlins will be needed for installation. Rather than having 2 4 purlins every 12 it would make far more sense economically to use 2 6 purlins every 24. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.

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. Snap a chalk line horizontally across the roof two feet down from the top. A roofing square is 100 square feet. How to install metal roof purlins.