Flooring Tile - radiant heated floor under tile

I am going to install electric radiant heated floor in my basement bathroom. The floor will be tiled. I the radiant heated floor company recommended to use 1/4" or 1/2" cement board over concrete slab to reduce heat loss to the slab. I wonder if there is some liquid mortar that can be powered instead of using cement board. The mortar should be good heat resistant. Also what type of mortar should I use over radiant heated floor wires to seal them, level the floor and create a good substrate for tile?

Just courious which Radiant Co. are you talking to?(whos system)

WarmylYours

I had never heard of doing this before so I did some checking around..What I basicly found out is that doing this with cement board makes little sense however doing it with one of the foam backer boards is a good idea.-Mfg. of the foam boards are Wedi and Bonsal(pro panel)The feeling was that the board should be bonded to the slab w/ a latex modified thin set (not dry set) since without the fasteners, that would normaly be used, the bond is up to the thin set.

I've never heard of putting CBU on cement, either. There's no way to anchor CBU to take advantage of the properties of it, so you're just adding more of what you already have. It makes no sense why they'd suggest that. Perhaps they misunderstood and thought that you were going over a plywood floor instead.

I need to cover the basement bathroom concrete floor with something which is very good heat resistant to prevent large heat loss to concrete slab from radiant floors. Any suggestion would be appreciated.

The two foam boards listed above!

How large a space are we talking about?

Slightly less then 24 sqft (roghyly 6' x 4').

you need to float over the coils after you install them any way i dont see what the panels are for.Do they go under or over the coils?If under it seems to me they woulkd need to be some sort of reflective board and not just a foam board.I've put these systems in 4 season rooms and this has never been mentioned before at all.You put the coil in the tracks and float over them allow to dry and set tile.If thatwas the case i think they would make it a one sided heat transfer instead of 360 degrees.Just thought here no scientific basis to this just random thinking:cool:

Both of the mentioned boards are made from Dow blue board and would defenetly insulate the floor or help the system by not tring to heat the slab.I had never heard of it either and stuck my foot in my mouth before I had the facts .I talked to both Warm Floors and one of the mfg. of boards.

thanx for the info ee3:cool: