Tile Job

[BlueBee]

Are there any tiling experts out there?  I’ve got some tiling work to do and I’m confused by the advice I read about tiling over a wood subfloor.  I have completed a few tiling jobs in the past, but they were on concrete.  The only real problems I’ve had to deal with on the concrete was potential crack movement over time.  I’ve used Ditra to deal with that concern.  No failures on those jobs after many years.

So now I want to do some tiling on a wood subfloor.  16” center floor joists.   Solid wood planking for a subfloor.  Probably a 1950s built house.  Pretty solid floors, no bounce.  What is the best way to proceed?

As I understand it, there are 3 major problems tiling over wood.  Flex in the structure, different coefficients of expansion between wood and tile, and adhesive bonding of the different materials. 

I think I’m OK on the flex, but how do you really deal with the different coefficients of expansion?  A product like Ditra would work, but its $1.50 a sq foot just for the Ditra!  Cement board is cheaper, but how does cement board account for the mismatch between coefficients of expansion when it’s screwed to the wood floor with a hundred screws?

I saw some strange new cement board at Menards (Midwest home improvement chain) tonight that was made of a mixture of cement and balls of Styrofoam!  It was as floppy as a pan cake!  Pretty strange stuff, indeed.  How do you use that stuff?   

[carlfaba10t]

What i would recommend is the cement board glued down with regular panel glue over the sub flooring.Seal all seams where cement board comes together. First check complete floor for loose nails or warped boards,use a large nail punch to reset any loose nails or use counter sunk screws to tighten up flooring before laying tile.The other thing you might consider is using smaller tile,you can buy 4" or 6" laid on Fiber screen to make 12" tile pieces.And if you are good at grouting it will not take that much more time to Finnish. 12 and 16" tile should be used only on solid concrete floors.

[kathyp]

ditto the cement board.  it makes the project so much easier.  didn't seal our seams but it was a tight fit on all pieces. 

not an expert on this other than my own projects, but over the cement board we have used the 12 inch tiles without problem.  don't know that i'd do that right on sub flooring because of the warping/flex/uneven issue.

we just finished a room that had a kind of crappy wood floor.  put down the cement board.  tiled with 12 inch tiles.  sealed it.  it turned out great.  it was about a 12 X 13 room and it didn't take that long. 

[BlueBee]

Thanks for the tips Carl and Kathy. 

I concur that you need a good surface to bond the tiles to and cement board certainly fulfills that requirement.  My concern with cement board was my belief you had to screw the stuff down.  Screwing cement board seems to defeat the idea of matching the coef of expansion between tile and cement board AND it makes any future repair/replace an absolute NIGHTMARE. 

I LOVE the idea of just gluing down the cement boards!  That really solves all my concerns if it works.

You know, the DIY forums are a lot like the bee forums.  The experts swear there is ONLY one right way to do things and if you don't follow them EXACTLY you will fail!  I've laid tile before and I know it isn't brain surgery and I'm not trying to build a taj mahal.  I just don't see any point of going to some of their extremes (1000 screws) for something that will probably be replaced in 10 years anyways (due to fashion changes).  It's funny because I've got a place where the previous guy tile right on top of luan....and it's still in good shape.  If the DIY gurus could only see that job! 

Again, thanks for your more sane advice.   

[Michael Bush]

I agree with the above.  I've had the best luck on cement board.  Flex, though, seems to be the biggest issue.  You can also beef up the floor from underneath if you have access (like the basement) and you can put extra boards in there.  You can either cut 3/4" plywood and put between the joists up under the floor, or put extra floor joists between the existing ones, or put 2 by 4s across between the spacing of the joists.  Some of it depends on where the flex is.  If the flooring is thin and gives between the joists or the joists are on the small side and spring when you walk...

[AllenF]

Backer board first then tile.   We see backer board even on metal stud walls and 3/4" advantech flooring.   

[BlueBee]

OK, thanks for all the good input.  I will go with cement backer board for the kitchen floor tile and I think I will forgo screwing them down; and just use the glue (or latex thinset) to secure them in place.  Well, I should say the glue and the WEIGHT of the board + tile.  

What about for the bathroom floor?  I’m kind of leaning toward a membrane product (like Ditra) since it provides waterproofing.  Don’t know how many spongy (water penetration) bathroom floors I’ve seen recently.  A lot.

[asprince]

We have have installed acres of tile.  On a wood floors make sure the sub floor is sound and tight. We then use thinset mortar between the subfloor and Hardibacker fiber board. Screw it down with treated screws per manufacturers recommendations. Apply tile directly to Hardibacker using Ultraflex thinset mortar. The only time we had issues was with 36 x 36 tiles. No more large tiles on wood floors.


Steve