How deep are slab foundations?
The foundation that your house is built on can have a major impact on the structural integrity of your home. A slab foundation is made of concrete that is typically 4″–6″ thick in the center. The concrete slab is often placed on a layer of sand for drainage or to act as a cushion.
How thick are mat foundations?
Depending on the total load applied to the mat and underlying foundation system, the thickness of mat foundations can vary from 1 ft (0.3 m) to more than 20 ft (7 m). The reinforcing system in the mat can be quite substantial, with heavy reinforcing bar mats in the bottom, top, or both locations within the mat depth.