Pole Barn Roof Purlins

Here is the formula for calculation of a roof purlin.

Pole barn roof purlins. If you are planning upon going with edgewise purlins across a single truss you are going to run into an uplift problem. Dear pole barn guru. Pole barn framing nails are typically in the 16d to 20d sizes truss connection 40d and 60d for 2x6 purlins on edge used for post spacing trusses. Purlins placed flat will not span eight feet so eliminates this option.

Purlins are used to attach the roof steel to the building. In order to answer your question properly i will have to make a whole bunch of assumptions. Hi i saw on your webpage the pole barn guru stated the trusses could be spaced 12 apart i called and was told it is a double truss one on each side of a post that is on 12 centers. When installed correctly they create a diaphragm effect.

I will assume this is a single truss code minimum snow load 4 12 roof slope and 29 gauge steel over purlins 24 inches on center o c. To strengthen the roof system truss clustering cross bracing and wind bracing is recommended at both end of the buildings and every 20 for longer span buildings. Purlins 24 oc are typical along with the bottom bracing shown. With trusses spaced 6 feet on center can you lay 2 4 purlins flat.

My question is can i use 2 x 4 on edge spaced. Reader dave in michigan writes. That is exactly what i have double trusses on each side of a post on 12 centers. Cos of live load dead load x cos of the purlin spacing x purlin span squared 8 x sm section modulus of the member x duration of load 1 15 in areas with snowfall x cr repetitive member factor of 1 15 where members are 24 on center or less fb fiberstress required.

Installation of pole barn purlins purlins are dimensional lumber that are fastened to the top chord of trusses connecting them together for bracing purposes. Can 2 4 roof purlins span 12 feet. The purlin are ultimately used to fasten the roof steel providing a diaphragm effect along with the siding when properly engineered and installed.