Perlin Size For Metal Porch Roof

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.

Perlin size for metal porch roof.

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. Cut the last purlin to size with tin snips if necessary. Move two feet down the roof and snap a horizontal chalk line. For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.

For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. Twist is measured with the zee laying on a flat surface under its own weight. If you want to know how to support roof purlins they are usually supported by 2 4 or 2 6 struts or posts. Do all roofing projects require purlins.

The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. 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. Dead load will be the actual weight of the roof steel and the roof purlins. 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.

Net variation for combned dimension. Engineered purlin metal mart offers a complete line of engineered purlin material. Cee purlin lengths are cut to length from 6 45 in 1 8 increments though 20 and 25 are the most commonly chosen lengths. 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.

The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. Install the second row of purlins just like the first cutting the end piece to fit. The standard of purlin length will vary anywhere between 100 to 300 mm while the thickness will vary anywhere between 1 to 3 mm.