Floating Slabs

A floating slab is a type of foundation system used in construction where the slab is not anchored to the ground, but rather “floats” on the surface, typically over a layer either select fill dirt, crushed stone or gravel. This design is commonly used in areas with expansive soils, which can cause significant movement due to moisture changes, or in regions with a high water table. Floating slabs are particularly advantageous for constructing garages, sheds, and small to medium-sized buildings, offering a cost-
effective and efficient solution.

The construction of a floating slab begins with site preparation, which includes excavating the ground to a certain depth and then laying down a base of crushed stone or gravel. This base provides a stable and well-drained platform, helping to distribute the load evenly and reduce the risk of settling or shifting. On top of this base, a layer of plastic sheeting is often laid to act as a moisture barrier, preventing ground moisture from rising into the concrete. Next, forms are built around the perimeter of the slab, and
reinforcing steel bars (rebar) or wire mesh are placed within the forms to provide additional structural support.

Concrete is then poured into the forms and allowed to cure. The thickness of the slab can vary depending on the building’s requirements, but it typically ranges from 4 to 6 inches for most applications. The edges of the slab may be thicker, creating an integral footing that enhances the slab’s load-bearing capacity. Once the concrete has cured, the forms are removed, and the slab is ready to support the structure. This method provides a solid foundation that can adapt to minor ground movements without cracking or becoming unstable.