i looked through your installation guide and didn't see an install setup with a traditional mudset on top of a plywood subfloor.  the closest i saw was the one with the cement backerboard.

our tile guy does traditional full mudsets (no cement board), and he likes to use wire lath.  is it possible for him to simply put in his mudset, and then to install step warmfloor in the thinset just under the tile, but above the mudset?

hmm, maybe i don't understand.  what i'm proposing is that he do his mudset with the metal wire mesh and let the whole mudset "cure".  i've seen him do this before in our other bathroom.  when he is done, the mudset just looks like a cement floor, no metal lath showing.  the metal is a good 1/2 in or so under the surface (old school tile guy).  i am thinking that step warmfloor gets embedded into the thinset on *top* of the fully cured mudset with the metal wire lath buried deep in the cured mudset. (and the tile on top of the thinset)

are you saying that even that far down away from the heating elements the wire lath would still pose a problem?

thanks