I am planning to place 3/8 in. thick ceramic tile on my 80 sq ft kitchen floor over an electric heating element.. I would like some feedback on the proper underlayment support for this project while keeping the additional floor height to a minimum. The joists are 2x8s placed 16 in on center. Next comes sheets of 5/8 in. plywood with an additional 1/4 in. of plywood on top. The tile store recommended taking up the 1/4 in. plywood and laying down 1/2 in. cement board. Then install the Flexterm heating elements to the cement board and spread the thin set adhesive to accept the tile. Is anyone familiar with this process?
Ralph