Floor Slab Thickness

Joists in home construction are usually made with 2 by 10 or 2 by 12 lumber.
Floor slab thickness. 6 8 inches 0 15 0 2 m side walks barn and granny floors. The floor joists comprise the bulk of the floor thickness. 5 6 inches 0 125 0 15 m porches home garage floors. Typically a project specification will reference aci 301 specifications for structural concrete which in turn references aci 117 specifications for tolerances for concrete construction and materials.
The actual width of those boards however isn t identical to what their name implies. Capillary break layers under floor slabs are typically comprised of 6 to 8 inch thick layer of 3 4 inch granular material that is gap graded to increase drainage rates. A 2 by 10 joist is really only 9 1 4 inches wide and a 2 by 12 is only 11 1 4 inches wide so depending upon. Ubc recommends minimum thickness of concrete floor slabs supported directly on the ground to be 89mm whereas bcgbc4010a apply structural principles to residential low rise constructions determined minimum thickness to be 100mm.
Slab thickness tolerances has long been a point of contention between contractors and specifiers. 1 3 minimum thickness of slab on the ground. Standard floor joists are usually 2 by 10 or 2 by 12 dimensional boards installed on edge. The granular material serves as a capillary break and a place to store the water until it can be absorbed back into the surrounding soil.