# Concrete slab with / without footings



## stadry (Jun 20, 2009)

if you don't mind, i don't either :no: however, i NEVER built that way when i lived in binghamton :no: 12 x 25 is too large for a 1piece slab as it WILL crack somewhere near the slab's middle,,, rebar appropriately placed in a 6" slab but, if it were me, i'd put the $$ into a thickened edge or excavate properly


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## myvalk (Dec 22, 2014)

Thickened edge?


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## Daniel Holzman (Mar 10, 2009)

Your question can have a number of answers. If you are asking if building code will allow, then that can only be answered by your local building inspector. If there is no code, or you plan to build without a permit, that is a different question.

With concrete, the minimum cover over reinforcing bars is generally taken to be 2 inches on the soil side, 1-1/2 inches on top. This puts your bars basically in the middle of the 6 inch thick slab, where they are close to the neutral axis, and provide minimal strength, and do little good except reduce shrinkage cracking of the concrete. More important to the durability of a thin concrete slab is the preparation of the subgrade (the soil supporting the slab), the quality of the concrete, the curing of the concrete, and the installation of control joints.

So certainly you can use a 6 inch thick slab for the floor. The slab is not suitable for the foundation of the building, for that you will either need strip footings around the outside of the building, or individual footings to support the posts that will hold up your building.


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## Bondo (Dec 8, 2007)

Ayuh,.... 'round here, alota floatin' slabs for garages 'bout that size are done with an 18" x 18" footer around the perimeter, jumpin' up to the 4" slab inside,...

Run 4 runs of rebar through the footer, 'n steel mesh in the 4" slab inside,...

J-bolts/ anchor bolts can be put in the wet concrete, or drilled later,....


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