we've got several issues with our ceramic floors in the kithen and adjoining laundry room. Approximately 30% of our 12X12 tiles have cracked. Most of the grout has loosened and in some spaces we can see the thinset as a result of just sweeping the floor. In addition, the floor in the laundry room is not level--it drops 1.5 inches over a 5ft run. We must replace it all. Our concerns: are the floor joyces (2X8 16" OC conforms to local code) strong enough to support the tile or must we strengthen them? If not strong enough, how could we strengthen them--the basement is finished and under the kitchen arethe mechanicals. Would replacing the subfloor with 5/8 inch cement board solve the problem? We want to maintain the level of the ceramic tile with the adjacent finished floors.
appreciate any suggestions.