wrote in message
oups.com...
pouring a slab foundation on top of existing 4 inch concrete patio.
code calls for 2 inches of sand on top of 10 mil visqueen.what do you
guys think? should i just roughen it up and pour on top? Visqueen is
there as a vapor barrier.


using your words

foundations are not poured on top of patio's.

With out a LOT more SPECIFIC information , can not see it from here