Soon the tiles will likely also begin to crack.
To rehash what you probably already know:
DITRA requires a minimum of a 5/8" subfloor. Minimum, minimum, minimum. The floor also must meet deflection minimums of L/360. Again a minimum.
With information about joist size and joist spacing and joist spanning you can determine the deflection criteria of the existing structure and what the "MINIMUM" thing to do would be since we are obviously talking about a minimum kind of customer.
There is no grout that will hold up under the circumstances you suggest you have to deal with.
Using caulk is just plain a stupid idea for a floor.
The simplest path of least resistance is going to be to go below and start installing some beams and lollies.
I suppose down below is a "finished area" and he won't allow any modifications.
:sad:
To rehash what you probably already know:
DITRA requires a minimum of a 5/8" subfloor. Minimum, minimum, minimum. The floor also must meet deflection minimums of L/360. Again a minimum.
With information about joist size and joist spacing and joist spanning you can determine the deflection criteria of the existing structure and what the "MINIMUM" thing to do would be since we are obviously talking about a minimum kind of customer.
There is no grout that will hold up under the circumstances you suggest you have to deal with.
Using caulk is just plain a stupid idea for a floor.
The simplest path of least resistance is going to be to go below and start installing some beams and lollies.
I suppose down below is a "finished area" and he won't allow any modifications.