I have done it down to less than an inch and it works but I have a special
procedure to ensure that it is bonded to the old concrete.

"Steve DeMars" wrote in message
news:Q0AHe.4216$mu6.3085@okepread04...
I have a garage, 17' X 20' inside area. It is a converted carport . . .
There lies the problem . . . The carport was poured with a "hump" in the
middle running across the 20'. This was so the rain blowing in from front
are rear would drain. Well now I have decided to make this area into my
shop, I have a problem. I want it to be level. In the center the thickest
I
can pour is 1.5". Any thicker and it creates all sorts of problems, like
doors not opening. As I go down the slopes it will get to be about 3.5"
thick. The existing sloped slab is over 20 years old with no cracks.
I have been told that if I pour it this way, it will crack . . . Any
suggestions appreciated . . .