d wrote:

The contractor insist that a plywood layer is not suitable for my
case. He said when he does new constructions he uses 3/4" plywood
because the sub-floor is not as strong as older homes so the plywood
is needed for structural needs. The wood subfloor you see in the
pictures are pretty thick and these types of homes don't need a layer
of plywood (mine was built in 1960). On the adjacent rooms where there

How thick is the subfloor in your picture? Most subfloors are 3/4".
Hardwood flooring is usually put right on top of the subfloor, there
is no plywood underneath.

It looks like 2x6 cardeck which would be very solid 1/4 inch hardy
right over the top.

The subfloor is about 1.5" thick. This is how thick the subfloor is on
the cover to the craw space (on top of the 1.5" is the actual hardwood
floor on the cover).

Now my neighbor told me that the kitchen subfloor has been replaced
before due to termite damage, so it may not be as thick as the rest of
the house..

It's all done now. Subfloor + 1/4" hardyback + thinset + US made 13"
porcelean tile. It feels fine. The cabinets, frig, stove and
everything else is in, and the tiles didn't crack during the install.

With just the 1/4" hardyback installed, I walked on it and it feels
soft. I was quite upset thinking that it won't be enough. But after
the thinset and tiles are layed down, it feels much better now.

I didn't know the subfloor were not the original ones when I started
the job, had I know that, I would've insisted on either 1/2 hardyback
or a layer of plywood. Oh well. I am pretty careful anyway and walking
on it wearing slipper it feels pretty sturdy, for now.

Thanks everyone!

Raymond