Spacing of studs in Advanced Framing more than 2 stories
I am building a 1 1/2 story home and am using advanced framing. I hope to stack all my framing using 2×6″ studs 24″ on center. Only problem is we have a walk out basement. The framing on the downhill side is: basement 82″ high, 1st floor 8′, 2nd floor 5′ 2″. If I read the IRC code right (mine is 2003), section [602.9] says cripple studs in the basement greater than 4 feet high are considered an additional story. And then in Table 11 for stud spacing [602.3.1], don’t I have to consider my home as Roof & ceiling + 2 floors? That requires 2×6″ framing to be 16″ on center.
My hope is the code has been updated or accepts 24″ on center framing as long as the studs, joists, and rafters are all stacked over one another.
Interpretation appreciated.
Tom
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Replies
Tom,
I'm not sure what the code says, but if you have a question about stud spacing for a new home, and if you aren't sure of the answer, the best person to answer your question is an engineer. For one thing, an engineer can review your plans and understand your loads -- something we can't do from your brief description in the paragraphs posted here.
I think in the past we have used 2x8 24" O.C. for the cellar in your type of situation.
Martin Holladay has given you the best advice. The IRC (residential code) is prescriptive and therefore gives building requirements to follow without actualy engineering a solution. The IBC (building code) says it can be engineered. The latest verson is 2012 but most buildng deparments are using 2006 or 2009 depending on where you are. As for whether it shoud be a 2x4, 2x6 or 2x8 walls, it depends on the span of the floor and roof that is being supported, wind loads, and the finishes on the walls, among other things. In many cases it is actually the potential crushing of the plates as wood is stronger parallel to the grain versus perpendicular. You therefore need a bigger area to get more surface on the plate. As you might have guessed, I'm an engineer.
As Corian states when we used the 2x8 studs we were able to meet the crushing factor. All plans need to follow engineering rules. I agree. My first post was basically to state that staying at 24" centers is possible, at least it was for us, with a set of engineered plans.... All plans need to be checked of course individually for many local factors and for all the particular details of the structure.
Corian, help out the gent with the need to drop his ceiling from his trusses....
https://www.greenbuildingadvisor.com/community/forum/general-questions/23088/rigid-foam-ceiling-question
On the 2009 IRC, Table R602.3.1, you can space 2x6 24” o. c. up to 14’ high walls when supporting two floors and a roof, which seems to be your case. This table is for walls exposed to 100 mph winds or less in seismic design categories A, B, C, Do, D1 & D2.