Thin backer board for installing tiles...

hi, i'm doing a complete kitchen remodel project right now and have a question about the kitchen floor.

the floor in the rest of the house is engineered oak. with the underlayment and the wood it's 5/8 inch thick above the plywood substrate.

the old kitchen floor is vinyl. it is installed on top of a 3/8 inch particle board backing "glued" onto the plywood substrate.

i have 2 questions:

1) how do i remove this flacky, glued on particle board? i was thinking of cutting it up with my circular saw set at 1/2 inch depth. will that be hell? how else to clean that crap out?

2) after i do this, is there a way to lay the tiles so it's the same thickness as the hardwood? or will i have to put down the concrete backer boards and have the tile be about 1/4 to 3/8 higher than the hardwood floor?

this is driving me insane... please help!

thanks!

 

Unfortunately, there are few ways to get that particle board out without sawing it. Your idea to use a circular saw is a good one, but I'd also get a reciprocating saw to get the corners, too.

How does the floor line up now? By the sounds of it, the oak/vinyl transition must have a wood or metal reducer there presently.

Although I don't think you can get flush if you replace the 3/8" particle board with new plywood, you can come very close. Most tiles have a cushion edge on them, which will help. You'll have to put un-cut tiles along the wood to do this. It'll be close as far as measurements go. It's rarely a good idea to tile directly on wood, so if your mind is set on it, do a dry run first. Keep in mind that the thinset will take up about 1/8".

If you had to, you could always use a good-looking profile there. Schluter has the RENO transition, which would be installed the same time as the tile. Here, you'd use the 3/8" plywood, cover it with DITRA underlayment (which would make it flush with the wood) and then tile over top, including the RENO profile. It's made to accomodate various tile thicknesses.

For curiousity's sake, how thick is the subfloor under the wood and particle board?

 

i will try to clear up my posting a bid...

the substrate of the house is plywood, so that's perfectly level and on the same height for the dining room and kitchen. the dining room is not covered in oak hardwood, including the underlayment, it's about 5/8 inch thick.

the kitchen now has particle board on top, about 3/8 inch, then two layers of vinyl, maybe 1/8, so total about 1/2 inch. it's just a hair lower than the dining room. i have a oak T-plate covering the transition, so it looks pretty good.

so my question really is can i lay tiles/stones so that the wonderboard, plus morter, plus tile/stone all add up to only 5/8 inch thick? or will the end result of the tile/stone job will always be thicker than 5/8 inch and i'll have to use a reducer?

are there 1/4 inch wonderboards? so 1/4 + 1/8 + 3/8 = 3/4 inch total thickness... just a little over 5/8 of the oak floor???

thanks again friends!

 

Thanks for the clarification.

To get it perfectly flush, install DITRA and set your tile on it. It should come out perfect, since DITRA is only 1/8", not 1/4" like CBU is.

Installing DITRA is easy. You'll only need thinset and a box cutter knife.

I noticed that you added 'stone' to your post. The above arrangement is good for ceramic, but you would have to beef up the floor with more underlayment first if you wanted stone instead.

Stone requires a minimum 1.25" of subfloor+underlayment and a much stronger support structure underneath.

 

I think I see what your getting at.

But regardless what goes where, you need to leave expansion for the hardwood floor at the tile transition. A reducer or "T" molding needs to be used.

Butting the tile to the hardwood, is asking for a failure.

 

Very true.

There is the tried and true method of installing silicone or latex caulk that matches the grout at that juncture. Any gap from 1/8" to 1/4" will suffice. If you use a 1/4" gap there, try to put foam backer rod in there before filling it.

You can use the Schluter RENO-T as well. It installs the same time as the tile and isn't as obtrusive as a wood reducer.