I plan to use 12X12 granite tile for our kitchen countertops. We have installed a 3/4 MDF top over the counters. I have since heard that Type I mastic is not recommended over masonite, etc. Others have told me that Kilz as a primer or scarifying the MDF will allow the mastic to "hold" the tiles. Also, can the tiles be butted and grouted only in the chamfered edges or should there be a tiny gap?
Thanks for and help.
Tom