Should I put a moisture barrier between a concrete floor and ceramic tile?
You should already have a moisture barrier between the concrete and the ground. The only way to economically put a moisture barrier in is to seal the concrete floor which will keep moisture from seeping up and then install concrete board on top of the concrete floor. You cannot set the mastics whether they be thinset or some latex/epoxy concoction on top of a sealed floor. They will not properly adhere. So you have to glue and screw concrete board, tape the seams with tile tape and thinset; let it dry; then trowel your thinset and lay your tile.
