What does the subfloor consist of? What is the overall thickess of the
subfloor? If I remember right, the subfloor needs to be ay least 1.25"
thick to provide a stiff floor to avoid tile or the grout cracking.
If it is wood, the wood could/will absorb the water out of the thinset
before it properly cures. The result will be a weak bond between the
tiles and the subfloor. This will lead to cracked grout and loose