Install tile over oak floor with plywood over it?

[anne1]

We would like to install some sort of tile over our kitchen floor. The house was built about 1920, very solid home with an oak hardwood floor underneath in the kitchen and plywood over that (I think 1/2" plywood). The joists are about 16" under the floor. Currently there is vinyl flooring over the plywood. Could we rip that up and then put down some sort of moisture barrier and then put say 1 ft. square tiles over the plywood and oak floor underneath?

[anne1]

From the basement looking up the boards there are 6 in. wide. Could that be a sub layer under the oak flooring?

[LazyPup]

If your house is circa 1920 most likely the boards you are seeing in the basement are the underside of the oak flooring. The concept of installing subfloors did not gain great attention until post WWII.

[floorman]

What you are seeing is the subfloor.That is what was used as subflooring up until the 60's sometime,maybe on a diagonal as well?No matter,you can set tile over the hardwood with a layer of min.1/2 plywood screwed and glued.Space the sheets 1/8 of an inch where the sheets meet and at the wall line too.Screw the sheets every 2" on the seams and every 4 to 6" in the field.You need to tighten this floor up as much as possible.You may even want to screw the planks before you lay the plywood.
Make sure you use a thinset that is rated for use over plywood cause they are not all the same and you need to read the bag.
Of course you know the best alternative here is to remove the hardwood down to the plank use 5/8 ply and then 1/2 c.b.u. then tile but you can tile the way i just mentioned without fear[8D]

Floorman
floorlayers union local 1310

[anne1]

Thank you for the help on my questions!

[Tom McNall]

Does your florr vibrate if you jump up and down? Do you here the china in the cabnets tinkling? If so, strengthen the floor before adding tile. For ceramic the formula is L (for load)/360 and for natural stone L/720

Have Fun eh?
Tom McNall
Great Northern Stone
www.greatnorthernstone.com
www.marblecleaning.net