Steel Roof Purlin Spacing

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.

Steel roof purlin spacing.

They give added support to the roof and also provide a nailing surface for the end panels and drip edge. Also known as sheeting rails purlins create the roofing members of the secondary framing of a steel building. This will depend upon the type of panel that is used and the thickness of the steel. Once the purlin spacing is determined then the metal roofing panels are typically attached to every line of purlins.

We do recommend it however. Engineered purlin metal mart offers a complete line of engineered purlin material. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. The purpose of purlins.

The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed. 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. Secondly purlins tie the rafters together stabilizing and strengthening the structure s rigid framing. Do all roofing projects require purlins.

First the purlins support the roof. Dead load will be the actual weight of the roof steel and the roof purlins. 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. An engineer will use a load chart in order to determine the spacing between metal purlins.

Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. The building was built 24 on center. The metal roof purlins spacing must be done correctly within narrow tolerances.

The wider the roofing panels the greater spacing distance you should put. Metal roof purlins are installed horizontally under metal roofs. However the screw placement diagrams commonly are based on the on center spacing center to center of the purlin rather than the gap between purlins to determine the length and spacing of the screws needed to prevent wind blowoff for various design wind speeds so pay close attention to that difference. Screw line spacing for metal roofing over metal purlins.

Metal building roof purlins provide three structural functions. There is a chance of damaging roofing sheets if you are failed to do so. The width of metal panels will determine the rafter spacing.