Floating slab on grade detail at exterior door.
Thickened slab at garage door opening.
That can be bent into the slab.
Type 1 is sometimes referred to as a thickened slab garage foundation and type 2 is often referred to as a stem wall garage foundation and type 3 is often referred to as a hybrid stem wall garage foundation for the reason that it is a combination of both type 1 and type 2 and is often used in areas that have highly plastic soils conditions such as is found in south dakota and other parts of the u s a.
There is a world of difference between the three types and which one will be.
I am leaning toward option 2 in the sketch i e.
Mostly for lightly loaded.
Option 2 completely blocks out the stemwall at the garage door and then a thicken edge is poured where the slab meets the footing at the garage door this seems to be the preferred method in western washington.
Extend the slab through the door opening to align with outside face of wall and thicken the slab edge locally at the door but not thick enough to bear on the wall footing.
Adding one course of block to a slab keeps the garage door framing farther up from the ground which may be necessary depending on the grade.
Some existing garage slabs will not have a thickened footing that runs beneath the slab in the garage door opening.
Yes use expansion joints.
Once we have determined what height the foundation wall needs to be above the lowest top of slab height and take into account the 12 inches of thickened slab the drop in the wall for an overhead garage door is pretty easy to calculate.
Finishingconcrete concretefinishingtechniques mikedayconcrete in this video i m teaching you about finishing concrete at the garage door openings.
It s like a garage door re.
I d also provide a 3 man door for entry.
The wall should have a key and 5 bars at 12 16 o c.
Pouring just a slab with a thickened perimeter is the least expensive and a perfectly acceptable option if you have good soil conditions not spongy.
Tie the slab to the foundation wall at the door.
The slab should have a thickened edge at the wall with a couple of 5 s running the lenght of the opening.
In these cases it is often required to dig under the slab and add a footing to support the new wall above.
The figure to the right shows one way that can be done.
The wall should be stepped down at the the door 8 10 below the top of the slab.