I‘m looking to replace a ceramic tile floor in my kitchen with a different style ceramic tile. The contractor says I have two options. He can either lay the new ceramic tile on the old, which will be cheaper than bringing up the old tile but then the floor will be raised 1 to 1 1/2 above current level. Or, he can take up the old ceramic tile but then he‘d have to remove the old layer of plywood and put down a new layer, which will be more labor-intensive and expensive. Is there any other issues regarding these two scenarios that I should take into account?
it is never a good idea to overlay anything, but it is your choice... myself i would remove the floor tile, check to make sure that the underlayment is well attached, if not you can screw down all the joints, put down luan board (screw and glue) which is 1/4 inch thick, using the correct thin set for what you have relay the tile floor. if there is any height differences around the cabinets simply use a small 1/4 round around the kick plates at the bottom of the cabinets, this will help with any cosmetic looks. when you get someone to lay the floor make sure they are bonded and insured and get any permits if needed for your area.
The largest advantage to taking up the old floor and replacing the sub floor is that you get a chance to see if there are any underlying problems (i.e. rot, unevenness, cracks). When I had my floor tiles removed and replaced, it was found that the original sub floor was improperly installed, was rotted by the kitchen door, and was hiding some structural issues. Sounds scary I know, but I would rather find out about these things and fix them before laying a new floor than having to rip up said new floor later to fix them.
Best to rip it out and start new. And start with a new sub floor made for and the proper thickness for tile.. NEVER, EVER use a thin 1/4 luan or ply wood.. This is totally inadequate for tile and goes against all tile hand book guides such as the ATC and TCA guide book.Minimum substrate thickness for tile is 1 1/4 not the 1 as suggested.Thus you must use 1/2 board or backer board ( properly installed) to meet minimum standards for stability for tile.There are other methods to install but this is very common way. Going over the old with new tile is a possible option but tile setter need to know what their doing. Thus raising floor only thickness of the tile and thin set. I d never go over it raising it that much. Any questions you can e mail me through my avatar and check my qualifications there. GL
