I'm going to be installing 12X12 marble tile in my bathroom next week. Any suggestions on the install? This will be installed over 1/2" Durock which is over 13/16" T&G fir and 13/16" plywood in places. Should I: - Put mortar on floor, or back butter the tiles? Either? - Use tape on Durock joints with mortar? Any other suggestions/tips/hints would be greatly appreciated... Oh, and thaks, Daryl for your insightful information!