Interface of interior non-load bearing and load bearing walls

[Gopher13]

I have a question about what is typically done at the interface of interior non-load bearing and load bearing cmu walls at the slab elevation. Should the thickened slab for the non-load bearing wall be poured directly on top of the load bearing footing, or should there be a layer of soil between the two? Please see the attached sketch for reference. Thanks!!!

 

[WARose]

I'd definitely have the slab do a turn down at the end and sit on that wall footing.

 

[KootK]

I vote for direct contact and no soil. Easy and should perform well. Nice sketch work.

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.

 

[Gopher13]

So away from the non-load bearing wall (plan north or south on the original sketch), where the slab on grade buts against the load bearing wall, there should be a thickened slab edge that bears on top of the strip footing as well? See the attached sketch for reference.

What happens if the strip footing settles? It would pull the slab on grade with it too I suppose, and a crack would develop in the cmu wall at a mortar joint somewhere? On the other hand, if there is a minimal thickness of soil between the bottom of the slab on grade and the top of the footing, that mass of soil would just drop with the strip footing, the slab would become unsupported at that location, and a crack would develop in the slab on grade. So if the strip footing does settle, I am left with either slabs cracks or cracks in mortar joints depending upon the detail I use? Does this logic make sense to everyone?

 

[EDub24]

I agree with the previous comments. I typically have it sitting directly on the footing.

 

[Gopher13]

Sketch I was referring to in my second post.......

 

[WARose]

Your sketch looks like the way to do it.

As far as your worries about settlement.....let me put it to you like this: you'd have a whole lot more settlement issues with that slab bearing on that short pocket of soil than from it sitting on the wall footing. I can promise you that pocket would not be compacted properly.