A slab is always monolithic, which means it is made from a single pour of concrete. Usually when the term monolithic is used, it is because the concrete footings and slab are poured at the same time. Sometimes footings are poured separately, but when you pour the footings and slab at the same time, it is always stronger. A monolithic pour eliminates a cold joint (or a break) between the footings and the slab.
Things You'll Need
- 1-by-12 inch forming boards
- Double-headed nails
- Rebar stools
- Wire mesh
- Bull float
- Screed board
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Prepare the area for your monolithic pour. Clear out all grass, weeds and other debris at least 3 inches beyond the area set aside for the slab and footings on all sides. This will allow adequate room for the forms.
Dig footings that are 18 inches wide and 18 inches deep. This is the area around the perimeter of your slab. Use 8 feet of 1-by-12 inch lumber to build your forms.
Place the form boards all the way around the perimeter on the outside of the footings. Hammer metal stakes behind the form boards every 12 inches. Use double-headed nails, which are easy to remove, to attach the stakes to the boards.
Put a 2-inch layer of sand on the slab floor. Water the sand and then rake it smooth. Place rebar in the footings on rebar stools. (If rebar touches air or earth, it will corrode.) Place rebar rods on stools around the perimeter of the sand and roll out wire mesh to cover the entire slab area.
Use a monolithic pouring system to pour the concrete from a pumper into the footings and slab area. The entire project--footings and slab--are poured together at once.
Smooth the poured concrete with a screed board (large squeegee) to smooth the surface and remove air pockets. Use a bull float, which comes on a long handle, to smooth the surface of the concrete and push the aggregates under the surface.