Summary: A concrete slab foundation is a single layer of concrete several inches thick. There are three types of concrete slab foundations and all have concrete footings
I'm starting a 2000 ft remodel in New Mexico. It seems all the houses here just set on a slab without a poured concrete footing just sitting flat on the ground is this a good idea?
It may look as if there is no footing, but all foundations have to have footings.
If there were no concrete footings, the concrete slab would crush or crack under the weight of the load bearing exterior walls and the load bearing interior walls.
A concrete slab without a footing would also heave and crack if exposed to frost, which is ground that is frozen.
New Mexico does have frost and thus a frost line. It may be just a few inches deep or more, depending on where in New Mexico you are building or remodeling.
When footings are below the frost line, the concrete slab is better protected from heaving and cracking.
I’m certain that in New Mexico building codes require one of the three types of concrete slab foundations pictured below: (Images Courtesy of ConcreteNetwork.com)
Frost Protected concrete slab foundation: Only works with a heated structure.
Slab-on-grade concrete slab foundation to form an integral footing: Poured thicker at the edges with re bar reinforcing.
T-Shaped concrete slab foundation: The footing is placed below the frost line and then foundation walls are added on top.
I hope this helps, Carl Heldmann