comercial steam room

I have question about the commercial steam room
All walls of steam room are not attached to outside walls of the building.
we did ceramic tiles with epoxy tile grout, under we did a mastic waterproofing with fabric then concrete boards
my question, do we need any vapor brier foil under if we done water proofing ?, or do we need isolation or two concrete boards with vapor brier foil between two concrete boards ?

Thanks and i am waiting for your answer

What does the manufacturer require? You should consider consulting them first.