Pole Barn Purlins

[Scott11T]

I have 8 ft truss spacing, which tells me I need my purlins on edge. However, I'm wondering how much of a role pitch plays in setting my purlins on edge or not. I'll have a 7/12 pitch. I'm worried about my purlins rolling on edge with a steeper pitch.

Thanks in advance for any input.

 

[SCATFEVER]

Maybe use hangers and put them between the trusses rather than on top.

RR Building shows installing purlins on edge in YouTube Videos

 

[MrSurly]

I put mine flat (on 5' center trusses and per drwgs) but there are many methods. I'm assuming because of your question that
1. You don't have a drawing or engineered plan to follow,
2. there's no local authority directing or requiring the build be done a certain way
If any of those apply, that's where you'd need to get the actual answer.

Barring those inputs, you'll need to do some math, I think. This outfit offers some guidance, may be helpful?

 

[fourbyford]

I built mine (6 pitch on 8' centers) with 2 x 6 purlins on edge by installing them between the trusses and using hangers. This is in an area with very high winds and potential for heavy snow loads. Never had any problems!