Slab and Stemwall Question

[bfitzwater]

Greetings, I am designing my next house to be built in Campbell Ca. It will have a 2,500 sq ft basement. Instead of placing footings for the stem walls I am planning on pouring a monolithic slab with the top edge of the slab keyed to accept the stem walls. I plan to use 24" thick slab reinforced with rebar and post tension. The edges will likely be

36" thick. The basement will also be used for my shop which needs to support the weight of a small 10,000 pound forklift for moving my projects. The Slab will also be the finished floor so I want it to be as perfectly flat as possible for my machinery etc. It just seems easier and cleaner to me to have one massive slab instead of separate slabs, footings etc.

Question is: with the weight of the 12" x 12' concrete stem walls be a problem to place on the edge of the slab even though it is heavily overbuilt or will the slab be strong enough to support the stem walls without excessive cracking? I realize there are a lot of variables here but I just want to get a "feel" for what you experts think or if you have seen anything like this before. I will have an engineer spec out the job, but just wanted to see if anyone has done something similar before.

The houses that were just built next to my property are all monolithic slabs ranging in depth from 12" to 36", even the garage is part the single pour.

I don't have a lot of experience in building, maybe about 8 additions built from the ground up, so any suggestions are appreciated.

[Bob Morrison]

You answered your own question. Your engineer will will let you know if the system you propose will work correctly. That's his/her job.

[Bobk207]

Help me out here Bob M

but a 24" PT slab on grade seems kinda burly

In my experience most machine shops in SoCal are in tilt building that have SOG of 6" or less.

Unless you have some special soil conditions this seems like a LOT of concrete, even for me :)

I just spent nearly 18 years working in a structural lab that had 24" slab (not PT) over basement shear walls at 10' on center, so now you know why I think a 24" SOG is kinda burly.......the lab basement SOG was only 12"

all this issues can be easily dealt with by your engineer

cheers Bob

[Glenn]

Is that 24" a typo? Most airport runways aren't that heavy. Explain what you mean by a stem wall. Not a term I'm familiar with in my part of the world..

[Italian Mason]

We have been seeing alot of "basments" in this area recently. The last one we did was in down town Santa Clara by the college. It was a historic house that had the basment re-done and expanded.

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