How would you design non-load-bearing exterior walls?
Hi all – I’m looking at a design like the Blue Sky steel-bolted moment frame. Basically, the steel corner columns and beams provide the structural integrity. The walls don’t need to be load-bearing.
Since the walls don’t need to do any load-bearing work, the only reason to have studs would be to support siding and other attachments like drywall inside, mounting TVs or cabinets, etc.
I’m intrigued by the ThermaSteel wall system. They’re steel-framed with solid EPS foam. They eliminated thermal bridging by turning the steel studs sideways, which is brilliant. But they’re standard size studs, which is a somewhat arbitrary decision given that they’re not being used the way they were intended, and these walls are designed to be load-bearing.
And since the studs are turned sideways, the full width of the stud faces the installer (of siding, drywall, etc.) So we’ve got a 3½ inch wide stud surface, instead of 1½ or 1⅝ inches. That’s sort of nice and luxurious, but it also seems unnecessary and possibly wasteful.
Since the studs in this context are only there to be able to attach siding, for example fiber cement panels, would it make sense to just design or choose a stud size and shape that serves that purpose? I’m thinking of something of normal width, maybe a little wider, like 1¾ inches. Minimally, it could in theory just be a narrow steel strap / sheet to be able to screw into, not a stud per se, but it might help to have a stud-like shape for more strength and rigidity. For example, a ThermaSteel stud is 3½ inches face/web with 1½ inch deep flanges. A non-load-bearing stud like I’m imagining might be 1¾ inches face/web and some TBD flange depth, maybe an inch or so, for bracing strength.
Would this make sense? How would you approach high R-value exterior walls that aren’t load-bearing? It seems like they need something like a stud in order to install the siding, and it also seems like we could use a lot less steel than load-bearing walls require, or ThermaSteel uses. I’ve looked at Hardie and Nichiha docs, and it seems like they just need a certain gauge steel at certain spacing – it doesn’t seem to matter if it’s a traditional stud shape or size, since I think the key issue is pull-out strength or screw retention.
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