Light Gauge Rafter Supports (Residential)

[Eldorado]

I typically do residential construction in wood, but have been asked to provide a light gauge steel roof framing design. Typically in wood construction, I use purlins as intermediate supports for rafters. Since I have dramatic span differences, I want to provide intermediate support for the steel rafters. Has anyone used back-to-back or box beam purlins to support a line of rafters, or is it preferred to have a rafter support brace at each rafter as shown in the attached detail.

 

[Eldorado]

Sorry, detail R1 attached.

 

[XR250]

You are much better off with a single brace at each rafter. I would try to clear the span the rafters and not use a brace at all.

 

[shobroco]

Yep, span the rafters if you can, but if not, put a diagonal brace on each one.