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The typical way of doing a concrete patio floor is to excavate soil at least 9", pour & compact gravel, then pour concrete.

I was wondering, what will happen if:

  1. Excavate post holes, past the frost line, in each corner of the planned concrete floor.
  2. Set rebars vertically in the holes
  3. Add horizontal rebars "connecting" the posts rebars.
  4. Add some more rebars, forming a "mesh"
  5. Set the concrete form (2x4's)
  6. Pour concrete, level and seal.

Basically, a concrete slab sitting on top of soil, with post foundations.

Will the concrete floor shift in level in no time? Will the ground crack and break it sooner than later? I live in Canada (Southern Ontario) where the ground goes through a freezing cycle.

  • The gravel bed is incredibly important. I have seen concrete footers like you describe used in areas where the soil doesn't pack. The thick gravel bed tho does the mist for you. – Tyson May 13 '16 at 19:36
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As long as the total contact area of the footings in consideration of the load bearing capacity of your soil exceeds the total dead & live load of the patio, then it won't settle into the ground.

As long as the footings are below the frost line, they themselves will not frost heave.

However - if the slab is still in contact with the ground, then it will still be susceptible to frost heave. The entire contact area of the slab with the ground - except the footings - will be above the frost line and can get damaged.

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