You will have to make sure your joists can handle the addition of considerably more weight from the plywood subfloor and any floor coverings.
How to fix uneven tile floor.
When you are dealing with uneven floors one option that you have is to use self leveling compound.
Reader photo by jeanne huber.
This compound can potentially be utilized on a concrete slab or a wood subfloor and it works well when you are dealing with dips in the floor.
Dig the grout from the edges of the uneven tile using your tile saw to break the grout surface and scrape it out without damaging the tiles.
How to fix uneven ceramic tiles.
Self leveling underlayment products can be used on concrete floors wood subfloors that are uneven but still in decent shape and even over ceramic tile floors eliminating the task of tearing.
How to fix an uneven tile floor.
Tile laying tricks for uneven surfaces.
A plywood subfloor will bridge any minor waves in the existing floor and leveling compound would help too.
An uneven floor or wall surface can lead to several problems in a tile job.
Tiles may crack pop loose or lip a condition that occurs when the corners.
Quite often the reason for uneven tiles is an uneven layer of thinset.
A reader would like to even out these travertine tiles.
Step 2 hold the tip of your chisel in one of the spaces around the uneven tile where it meets the wall.