I decided to go ahead and rip up the old vinyl floor in my kitchen (in progress...) and put down porcelain tiles. I had planned to put down a plywood subfloor but when I ripped up the vinyl I noticed that I had 3/4" OSB and 1/4" FiberFlor Supreme which is glued to the OSB and has all the seams filled.

My question is should I still put down plywood? If so then what thickness of plywood would I need if it is not adequate. Do the joints need to be filled as they were before?

Googling FiberFlor only had a few hits but
the one site seems to say that it provides an ideal substrate for ceramic floorcovering?! Thoughts?

In either case is it essential to get all the bits of vinyl floor off before starting?

Thanks for the advice!

Okay-- First, I have to tell you this is the first I've ever heard of FiberFlor. I also got almost nothing off Google, but I DID get a good hit on a Yahoo search. As you say, it DOES say that tile can be set over it. However, there's nothing else there. I don't even really know what this stuff is, or what it looks like, or what its main composition is, other than it's organic fibers and some kind of resin. Personally, I'd pull it and use either cement board or Ditra, only because there are alot of "charletons" out there that make all kinds of outrageous claims, and I've learned to trust nothing I haven't seen test results for myself on, or that isn't advocated specifically by the TCNA.

That said, IF I were going to leave it down, yes, I'd be sure to pull every last trace of the vinyl.

Thanks Bill. I decided to rip up all of the vinyl floor and it wasn't as easy as I thought it would be. Thanks to the guy at Home Depot, I ended up renting a tile lifter and it worked like a charm. Definetly recommend it if the vinyl is stubborn coming up.

The FiberFlor went underneath the cabinets so I decided that lifting it was not an option. I didn't trust it either so I decided to put down 1/4" plywood just to be safe. It brought my total floor thickness to 1 1/4".
I just finished grouting it and it looks great. Hopefully I won't have any problems with flexing or cracking. The tiles themselves are porcelain so they might stand up a little better.

I would describe the FiberFlor as fine grain particle board. Almost MDF'ish.

1/4" cementitious backerboard would have been better than wood to tile over.

Matt
Cupan Custom Tile and Paint
tile contractor