we had our kitchen + addition/family room floors ceramic tiled 5 mos ago. The floors are adjoining. There is backer board sub floor w/ appropriate overlap beteween the rooms. There is radiant floor heat in the family room + a kick plate heater under the sink in the kitchen to provide heat. The tile adjoining the two rooms has cracked. Would the different heating + resultant difference in tile temperature be the cause of the cracking? Would installing radiant heat in the kitchen solve this problem ?. There is no other structural defect that we are aware of. Please Help!!