Perlin Size For Metal Porch Roof

The standard of purlin length will vary anywhere between 100 to 300 mm while the thickness will vary anywhere between 1 to 3 mm.

Perlin size for metal porch roof. The substructure to which the metal panels are fastened must be properly spaced and sufficiently thick to provide a roof or wall system able to meet required design loads. Cee purlin lengths are cut to length from 6 45 in 1 8 increments though 20 and 25 are the most commonly chosen lengths. The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. 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. Do all roofing projects require purlins. Available in cee or zee shape red oxide primed or galvanized 16 14 or 12 gauge sizes from 4 up to 12 flange widths of 1 1 2 up to 4 cut to your specified lengths hole punching available load tables available for all material. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet.

Dead load will be the actual weight of the roof steel and the roof purlins. If you want to know how to support roof purlins they are usually supported by 2 4 or 2 6 struts or posts. Net variation for combned dimension. 20 psf x 949 1 5 psf x 12 x 949 x 11 625 2 8 x 3 0625 x 1 15 x 1 15 972 75 psi.

Twist is measured with the zee laying on a flat surface under its own weight. Move two feet down the roof and snap a horizontal chalk line. 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. Snap the third chalk line two more feet down and continue down the roof until it is covered with purlins.

For 2x4s purlins the posts are spaced in 4 feet distance. A 2 nominal lumber thickness provides the maximum pullout values for both screws and nails when the fasteners penetrate a minimum of 1 into the wood. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to.