OK, one last followup (I hope).

Can I use thinset as a leveler over the 2-by subfloor? There is some
uneven-ness between the boards, maybe 1/8" at most and I'd like to use
the 1/4" wonderboard if possible (the subfloor is very solid, btw).

If I sand down the subfloor a bit, will the adhesion be sufficient for
the thinset? Then I plane to use tile mastic on top of the thinset
skim coat, wonderboard (durock) nailed on top of that and taped with
fiberglass tape and thinset. Lastly, the floor tiles.

Sound OK?

- Casey

(KS7J) wrote in message . com...
Hi All,

Bathroom project coming up. Part of it is to replace a wood parquet
floor with ceramic tile. Parquet is 3/8" thick over 1/2 or 5/8"
particle board over 2x8 T&G subflooring (nominally 1-5/8" thick). I'm
concerned about achieving the same level on the new floor.

Can I remove the particle underlayment and screw concrete backer board
(Durock aka Hardi-backer, etc.) directly to the T&G subfloor? My
instinct says it is stiff enough without additional plywood
underlayment. If I have to put a plywood base on top of the T&G I have
no hope of getting the tile floor to the same level as the current
floor.

TIA,

Casey