New garage construction concerning stem walls

[case464]

I am getting ready to build a garage with floating slab with stem walls and have a question about the stem walls.The stem walls will be about a foot above the slab.Should I block out for the overhead doors and let the slab sit ON top of a stem wall at the garage door opening or should I leave the stem wall and footing out of the areas where the overhead doors will be? Cost difference is not an issue just seems as though it would not be needed and would allow the entire slab to be independent of the stem walls. Also would make the pour much easier to leave them out as I could back the truck inside the foundation forms to make the pour
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[brownbagg]

why not pour the slab and then put one course of block on top of slab. you dont need slab imdepent of stem wall, because weight of slab and equipment working on projects, need to be on the footers

 

[case464]

Building on slope which requires part of the stem walls to be step down and taller

 

[GeorgiaHybrid]

case, I just finished mine with a 4' stem wall at the upper end and steping down the hill to a 7' high wall at the low end. At the garage doors, I poured a pilaster between the doors to allow a concrete wall around the entire perimeter.

Mine looked like this as we were stripping the forms:

The entire inside was leveled with gravel and the slab was poured on top of the gravel and left us with 3'-6" of stem wall above the slab when we were done. The slab was poured into the openings for the doors and on top of the footings on the high side. Everything else was poured on the compacted gravel.

 

[case464]

that is very close to what I will have except instead of 7' stem wall it will be 4' and 2' stem wall on the upper side and in the front. After I block out for the door openings I will be left with a 6" tall stem wall under the slab at the doorways and the pillasters between the doors will be 2' foot tall. My question is since it is a floating slab then should it be sitting on top of the stem wall at the openings and floating everywhere else.

 

[mebedave]

pour the stem wall with cut outs. keep the cut out lower than your slab by lets say 6" or more. Then pour your slab last over the top of the cut outs with a heavy slope in the area of the car door so water drains away and not under the door. I like to strike a control joint in the slab right inside at the door openings. Remember easier is not always better

 

[case464]

That is what the original plan was but to much time thinking waiting on the weather to get better had me wondering about the slab resting on the footing in one spot and not on the rest was a good thing or not. Why the control joint just inside the door?

 

[Steevo]

like the others, mine were done as drop-down sections in the stem wall.

 

[joes169]

I am getting ready to build a garage with floating slab with stem walls and have a question about the stem walls.The stem walls will be about a foot above the slab.Should I block out for the overhead doors and let the slab sit ON top of a stem wall at the garage door opening or should I leave the stem wall and footing out of the areas where the overhead doors will be? Cost difference is not an issue just seems as though it would not be needed and would allow the entire slab to be independent of the stem walls. Also would make the pour much easier to leave them out as I could back the truck inside the foundation forms to make the pour
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Personally & professionally, I prefer to not only rest the floor on the door openings, but also incorporate a min. 2" wide floor ledge into the entire interior perimeter. I've seen far more issues with settling floors on disturbed soil than floors sitting on a ledge. I'm kinda surprised it's apparently not a more common practice in the rest of the country.........

 

[mebedave]

Personally & professionally, I prefer to not only rest the floor on the door openings, but also incorporate a min. 2" wide floor ledge into the entire interior perimeter. I've seen far more issues with settling floors on disturbed soil than floors sitting on a ledge. I'm kinda surprised it's apparently not a more common practice in the rest of the country.........

We do key ways in the stem wall to lock the slab to the wall.

 

[mebedave]

That is what the original plan was but to much time thinking waiting on the weather to get better had me wondering about the slab resting on the footing in one spot and not on the rest was a good thing or not. Why the control joint just inside the door?

"Why the control joint just inside the door?" So when it cracks it cracks inside the control joint where it is not noticeable. And yes your right resting the slab on spot it does want to crack there, that's the reason for the control joint. Think about using a key way in the stem wall to hold the slab, it's better than just doweling the wall with rebar.