Subfloor base for bathroom tile

StevePax · 12-21-2009, 05:40 PM

The first layer of floor in my bathroom is 2x6 tongue in groove planks over 4x6 joists spaced 48" on-center. Under the bathroom, there has been some reinforcement done as well between the joists, especially around the toilet, etc. On top of that currently is 3/4 inch plywood, and then the current sheet vinyl is directly adhered to that. Well, that top layer of plywood is coming off (due to water damage), and the remodeled bathroom will be tiled on the floor. Here's what I'm thinking: First, 1/4 inch plywood over the 2x6 planks. Then, 1/2" plywood under the shower pan area, and the pan over that. 1/2 inch Dur-rock over the rest of the floor, and tile flooring over that. That means that the shower pan will sit at exactly the same level it used to (the 2x6 first layer, and 3/4 inch above that), and the rest of the flooring will be the 3/4 inch above the base that it was before, plus the thickness of the tile and mortar. Does that sound good? Does anyone have a better idea of how to do this tile floor?

firehawkmph · 12-21-2009, 08:05 PM

Steve,
Sounds like a pretty beefy floor. What type of house is it that you have the unusual floor framing, old post and beam or something like that?
Just from your description, the only thing I question is why bother changing to 1/2" ply under the shower pan? I would just run the durock wall to wall and be done with it. Thinset it in and use their screws like they recommend and you should have a tight water-resistant floor.
Mike Hawkins

StevePax · 12-21-2009, 08:54 PM

I can put durock under my shower pan as well? OK, so one layer of plywood over the 2x6 planks, either 1/4 or 1/2 inch, then 1/2" durock over everything, then shower pan over that on one end, tile over everything else, and vanity on top of the tile. Does that all sound okay?

The house really isn't super old - built in 1978. But when I look down in the crawl space, I see some posts sticking up, and the beams are all 4x6.

StevePax · 12-21-2009, 08:55 PM

I don't really want to put the durock right on the 2x6 planks, because I want to be able to thinset it down, and I don't want to apply thinset directly to the planks. Then, 15 or 20 years from now, the floor will be impossible to tear up to remodel the next time around.

firehawkmph · 12-22-2009, 09:32 PM

Quote:

Originally Posted by StevePax

I can put durock under my shower pan as well? OK, so one layer of plywood over the 2x6 planks, either 1/4 or 1/2 inch, then 1/2" durock over everything, then shower pan over that on one end, tile over everything else, and vanity on top of the tile. Does that all sound okay?

The house really isn't super old - built in 1978. But when I look down in the crawl space, I see some posts sticking up, and the beams are all 4x6.

Now I see said the blindman as he picked up his hammer and saw.

Are the posts sitting on a concrete pad, or are they buried in the dirt? Although you should have a scratch coat of concrete in the crawl area.
Anyway, I would do like you are saying above, screw the plywood down, thinset, durock, tile, done. Should be nice and solid. The durock under the shower helps to keep it water resistant. Why worry about plywood being right underneath the shower base?
Mike Hawkins

Mike Hawkins

Mop in Hand · 12-23-2009, 12:28 AM

What you have is called "car decking" in my neck of the woods. I would go a little different route. First I would screw 3/4" ply over the decking. I would use 2" screws. Then I would thinset Ditra over the ply.(except in the shower area) http://www.schluter.com/6_1_ditra.aspx and then set my tiles. Forget the durarock.

firehawkmph · 12-23-2009, 10:41 AM

MiHand,
I'm glad you posted the link for the ditra. I haven't seen that much in my area, but have been seeing it on Mike Holmes' show. Looks like a very good product. I am going to check with the tile warehouse I deal with and see if they stock it.
Mike Hawkins