After 2 years wire open in tapeMat

[therock]

We had a TapeMat installed in our master bath when the house was built 2 years ago under a ceramic tile floor. About a month ago, I entered the bath room and the GFI Breaker in the Thermostat was tripped or the red light was on so I assumed it had tripped. I reset the breaker and the floor will not heat anymore. After several attempts to locate the problem, the contractor changed out the Thermostat and had an electrician come in and check for the problem. First we checked for continuity between the white and black wire to the TapeMat and it read open using an Electronic Volt Ohm Meter. The electrician felt if there was an open it would most likely be at the factory splice so they dug up the splice, opened it and checked for continuity beyond the splice and still read an open. Now the contractor wants to tear out the bath floor and replace everything. I put a wire tracer (cheap one) on the wires but cant get a reading through the tiles. Is there a way to identify where the open is instead of tearing up everything and starting over? My email is [e-mail] and my cell is 3017306536