Floating Slab Vs. CMU Stem with Isolation
Floating Slab Vs. CMU Stem with Isolation
(OP)
I think this will be a fun discussion here. Do you prefer the floating slab detail where the slab and stem wall are independent? Or do you like them to be tied together like shown below (detail not be me but by an architect I'm working with)?
Personally, with this building being a 3-story load bearing wood structure, I like isolating the wall from the slab to avoid cracking the slab with settlement, etc.
Also, as an aside, I see this detail from time to time by other engineers/architects, and frankly, I don't think I ever like it. The slab will want to shrink to the center and want to pull away from the wall. But maybe I'm biased. Are there situations where the below detail is good that I'm overlooking?
Personally, with this building being a 3-story load bearing wood structure, I like isolating the wall from the slab to avoid cracking the slab with settlement, etc.
Also, as an aside, I see this detail from time to time by other engineers/architects, and frankly, I don't think I ever like it. The slab will want to shrink to the center and want to pull away from the wall. But maybe I'm biased. Are there situations where the below detail is good that I'm overlooking?






RE: Floating Slab Vs. CMU Stem with Isolation
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Floating Slab Vs. CMU Stem with Isolation
With the original detail posted, would it not make the most sense to place the insulation on the exterior of the stemwall thereby creating a total thermal break. The way it is shown it seems that the heat will escape at the wall edge and flow through the slab to the exterior of the stemwall.
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com
RE: Floating Slab Vs. CMU Stem with Isolation
That, and we went from 50 years ago mass masonry walls with no insulation to what we have today. I think the pendulum swung the other way, and I'm hoping we land back in the middle soon
RE: Floating Slab Vs. CMU Stem with Isolation
And i am so glad to hear another person reiterate the tail wagging the dog. I have been in many arguing matches with architects about CI and even a co-worker who is a forensic engineer that really specializes in Building Envelopes... Lets say i care more about my walls cracking then a little thermal short next to a giant curtain wall.
As for the original question, I nearly always isolate for the reasons you mentioned. I do sometimes tie them together for retaining reasons or at doors.
RE: Floating Slab Vs. CMU Stem with Isolation