Tile floors are heavy and tile is a hard material.
Proper subfloor for ceramic tile.
For this reason ceramic and porcelain tile floors can be considered somewhat delicate despite the inherent strength of the material.
Wood building materials contract and expand at different rates from natural humidity and exposure.
However you re not out of the woods.
Proper preparation of the subfloor is critical to the success of your ceramic tile installation.
Because of issues of moisture movement and adhesion ceramic tile will work well with certain types of subfloor underlayment systems and can go dramatically wrong with other subfloor materials.
It will break or dislodge if the surface bends under the load.
Concrete expands and contracts and that type of movement can also crack the tiles and the grout.
This guide will show you how to prepare your subfloor for a tile installation project to ensure that it s fit to support ceramic or porcelain tile.
It sounds like your joists are well within the acceptable limits of l 300 so your main concern is the deflection of the subfloor between joists.
Preparing a subfloor is an essential step for installing floor tile it provides a level surface that will allow the tiles to properly stay in place.
Cement backer board can provide a solid flat surface to install tiles on if you have a wood subfloor.
Laying tile on plywood.