2x4 Purlin Spacing For Metal Roof

They give added support to the roof and also provide a nailing surface for the end panels and drip edge.

2x4 purlin spacing for metal roof. For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet. Now if you are strapping the rafters 1x4 pt is usually used set at 2 intervals or closer and you double the first one at the edge of the metal 6. Spacing is typically 24 on center in low snow loads and is reduced based upon truss span and snow load. 384 x e modulus of elasticity for the lumber being used x i moment of inertia for the lumber size plugging in the variables.

5 x ps roof snow load adjusted for slope factors x purlin spacing x purlin span 4. Twenty four inches is a common spacing of furring strips for a metal roof. Without even running the calculations i would say there is a good chance the 2 4 purlins will not make the deflection criteria required for a roof framing member supporting steel. In some cases however the exact spacing of the rafters doesn t matter if the roof has other means of supporting the metal panels.

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. You don t have a nailing surface on the end of a 1x4. Panel basics corrugated metal panels often called tin because in the past such panels were sometimes made of tin are typically steel or aluminum sheets that are used as a roofing material. Metal roof purlins are installed horizontally under metal roofs.

Purlins are 2 by 4 feet and are installed much like metal roofing. The country inspector upon approving the plans seems to have written in per manufacturers specs regarding 2x4 purlins on 16 centers. I m fixing a partially completed pole building. 5 x 18 98 psf 144 has to be divided by 144 to give psi x 24 x 70 5 4 384 x 1 400 000 x 0 984 0 795.

The building was built 24 on center. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. The typical spacing standards for residential and commercial buildings are about 1 to 2 foot. If so you should use dimension lumber like 2x4.

Rather than having 2 4 purlins every 12 it would make far more sense economically to use 2 6 purlins every 24. We do recommend it however. 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 purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed.