Definition - What does Supported Slab-On-Grade mean?
Supported-slab-on-grade is cast when footings are already framed to raise columns. The grade slab rests on a layer of gravel and moisture barrier and the wall is supported by the footing.
An expansion joint is provided between the wall and the slab to relieve stress caused by expansion on hot days. Slabs-on-grade (also known as floating slabs) refers to concrete slabs that are directly laid on the ground over a prepared surface.
To prevent groundwater from entering the slab from the earth, a layer of gravel and bitumen is first laid on the earth. These slabs are popular in areas where ground freezing is not an issue.
Trenchlesspedia explains Supported Slab-On-Grade
Supported-slab-on-grade is supported directly on the framing and the design can accommodate the soil and water pressure forming a watertight structure. The supported-slab-on-grade is considered superior to the monolithic-slab-on-grade when it comes to long-term performance and integrity of the slab.
Slabs-on-grade can be used in places where the load-carrying capacity required is low or in loose soil and soils with varying compressibility. These slabs also efficiently spread vertical loads over a large area. To cast a slab-on-grade, the earth is first excavated to the required depth and compacted.
A layer of gravel and bitumen is first laid over which concrete is poured with or without reinforcement. The thickness of the slab is more at the edges of the slab, with reinforcement rods provided to strengthen the edges.