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Max Height of CMU Stem Wall

adamflyer's picture

I got my plans approved that have a 8" CMU stem wall with a max height of 48". I graded the lot but am still far from level and don't want to grade it any more. The max height difference for the foundation area is 7'4". I am trying to keep the footers on undisturbed soil so I don't need engineered fill. I'm under IRC 2012, 90mph exp C, Seismic Design cat B. A copy of the plans are here http://www.goldenfab.com/temp_share/House/House_Plans/Goldenstein_Residence_Plans_Rev_1.pdf

Looking at TABLE R404.1.1(2) on page 93 of IRC 2012 shows I can do a 10' stem wall with up to 4' of unbalanced backfill with the #4 at 48" vertical rebar reinforcing I have specified in the plans. However turning to page 188 FIGURE 602.10.9 it looks like I'm limited to a 48" stem wall for braced wall panels.

So if the parts of the stem wall that need to be 7'4" and the walls above are part of the braced wall calculations then a taller than 48" stem wall would be a no go per the IRC? Am I missing something? Surly the stem wall could be beefed up with more rebar anc concrete to be taller than 48"? Or are there other approved designes for a taller than 48" stem wall in IRC I am not seeing or another reputable design source?

I send my building official an email but am waiting to hear back. Hoping to hear how others would approach this.

Thanks,

Adam