Harold-- is the rebar @ 18" centers in addition to mesh or instead of?

I don't know what Harold did, but I laid mesh, then decided that adding
~1000 feet of 1/2 inch rebar was quite inexpensive ($250 or so at the
time) and it helped to keep the mesh more like flat. I had fiber mix
poured, too. I used up extra bits of mesh by putting a double layer
(above and below the rebar) at the doorways. I also have 750 feet of
radiant heat tubing in place (near the bottom of the slab), but have not
got heat hooked up to it, so I'm not chiming in on how well it works
yet, though I expect it to work well. Pay attention to the edge
insulation - I have a tiny bit of uninsulated face showing at each door,
but all the edges, including the edges at the doors, are insulated. It
wasn't too hard to convince myself that insulating under the slab,
around the edge of the slab, and also insulating the outside of the
stemwall all the way to the footing (which, naturally, has a drain all
the way around it) made good sense. Walls are SIPs, place is _well_
insulated all around, or will be when the ceiling is in place and
insulated above. You cannot go back and add more insulation or
reinforcement after the concrete is poured, so slight overkill, within
reason, is better than underestimating. Massive overkill wastes money.

Rebar is easy enough to put in yourself, if you have time/inclination.
Pouring & finishing the concrete is better left to an experienced crew,
IMHO, having done it both ways.

Take the time to bend corners (so that corner re-inforcement is a nicely
radiused bent rebar, tied into the rebar grid with adequate overlap, not
just crossing rebars held by tie wires). No reason you can't do that all
the way to the middle, but at least 3 grid spacings in from the corner
should be tied in that way, IMHO. Corners are stress concentration areas.

--
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