"Dante M. Catoni" wrote in message
...
My bathroom floor is constructed as follows from the bottom up
2" X 8" joists 16" on center
3/4" X 7" boards running perpendicular to joists
1/2" x 7" boards running parallel to joists (very wavy)
3/16" plywood?
ceramic tile

Within a few weeks of buying this house the tiles started cracking and the
grout popped out. I just took out most of the tiles by hand.

I was planning to remove the 1/2" boards and put down
5/8" exterior grade plywood
thinset
1/4" Hardibacker
then tile again

The floor will end up a little higher than it is now which is about even
with the hall, but it might still be ok. Would it be better to go down to
the joists and start with 1" ply? If I put thicker plywood on the joists
can I go directly to cement board or are there two layers for a reason? Is
there anything else I should consider? I want to do the job right and make
it last.


*It sounds as though you have a decent subfloor. What I would look at is
the joists. How long of a span do they have without support?

Something else to consider is that the previous owner may have put down a
fast and cheap tile job to sell the house. The tiles may be popping up
because they were not installed properly.