I don't know that I agree with Malcolm.

Good subgrade prep and compaction - yes. Nothing wrong with the
right kind of dirt, select fill preferred. No sod, no loam,

Mesh does not reinforce concrete.
Rebar in a 4" slab does not help, actually hurts.

Avoid re-entrant corners.
Concrete wants to be square, not rectangular.
Never exceed 12' in any direction without at least a contraction
joint, closer preferred.
Cut all contraction joints a minimum of T/4, that is, 1/4 or more
of the slab thickness. Most lumberyard jointers cut 1/4" deep.
Make sure the keel is at least 1" or you're wasting your time, I
prefer 1 1/2. If the contraction joints are sawed into the slab
(my preference) they must be sawed the same day as the pour as
soon as the concrete doesn't ravel under the blade. You CANNOT
wait and cut them the next day.
Curing the concrete is crucial. If you use a curing compound,
make sure it is compatible with potential floor
finishes/adhesives. A 3 day minimum full wet cure is the best.

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______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




"** Frank **" wrote in message
. ..
Contractors and DIY use groovers or saw cut control lines so
that the concrete will break at the joints. That's the plan but
more lightly the concrete slab will crack everywhere except at
the joint lines. For the concrete slabs I saw on patios,
driveways and sidewalks, it seems pointless to have control
joints. Expansion joints excepted, off course.

So the question is, when concrete cracks then how do you make it
break at the control joints more often than elsewhere?