"samurai" sammer003 @ yahoo.ca.spam wrote in message
...
On Wed, 24 Oct 2007 09:38:16 -0700, Manster wrote:

Mikepier wrote:
A few weeks ago I asked if I could tile over oak floor area in my
foyer 4'X15' and everyone suggested using some kind of underlayment.
Recently my wife and I picked out a tile that is 1/2" thick and is 11
3/4" X 11 3/4". This tile looks a lot more beefy than ordinary tiles
and of course costs twice as much. Now the problem is because it's
1/2" thick it would be a problem heightwise even if I used a 1/4"
backerboard. So my question is will this tile be less likely to have
problems if I go over the wood floor because it's so thick even if I
screwed down the floor at every joist.
By the way my combined subfloor and hardwood thickness is 1 1/2".


An 1-1/2 is a pretty thick sub-floor already without adding a 1/4"
board. If the oak floor is roughed up a bit and the joists are not
spaced too far apart and there's no flexing between them, you should be
fine. Someone mentioned sealing the sub-floor first, but I disagree. A
sealer may interfere with the adhesive you use for the tile.

I would be hesitant to put over oak floor, as it may let loose or
float(due to heat and humidity), and result in cracked grout. Oak
floors are just nailed in, and will 'creak' over time. Ever had a
squeeky wood floor?? Especially in a high traffic area, you want it
strong as possible.

To do it properly, remove the oak, then you'll have laths which are
over the floor joists. Put 1/4 plywood, then a thinset, then 1/4"
Wonderboard (or whatever to meet the desired other flooring height),
then mortar and tile. Be sure to use screws to secure the Wonderboard
throught to the joists.

You could even remove the laths, then you could nearly match your
existing flooring. You'd need minimum 1/2" plywood, and 1/2"
Wonderboard.

That would be a rock solid finish.

samurai.

Laths on a floor? Where are you? 1/2" plywood is NOT enough under 1/2"
wonderboard, 5/8" minimum for joists on 16" centers. If you need to keep
height down, use 1/2" ply over the joists but first put 3/4" between the
joists level with the joist top, with 2x2" attached to the joists under the
ply, supporting the edges, then install the 1/2" ply subfloor, add the
wonderboard then you have a solid base.