Drywall + Redgard okay for shower?
We are in the process of updating our master bath. My contractor has just installed the backing for the shower tile. He used USG 'Mold Tough' gypsum panels. He has been in business for 15+ years and provided several references.
However, everything I've now read online says that this product is not suitable for wet areas. He did apply Redgard (looks like three coats) over the wallboard. Will the Redgard adequately waterproof the gypsum? I'd rather not ask him to replace the drywall with durock, but if this is going to be a problem down the road, I need to address it now (before the tile is laid).