Tile Install underlayment questions

[BIGGU]

So i'm getting ready to put new flooring in my laundry room and looking for some advice. Right now the flooring in the room is some cheap vinyl roll over 1/4" plywood which is outside glued. In the hallway transitioning to the laundry room is 3/4 thick hardwood. Subfloor is 3/4" and joists are 16" oc.

 

I was looking at putting Schluter Ditra down which is 1/8 thick but I really don't like putting that straight on the sub floor because its thin-set'd to the subfloor and if you screw it up you basically have to pull the subfloor. Inset me into thinking I should just put an underlayment. Reading the Ditra manual they say thinnest underlayment is 3/8th that can be used with Ditra. So if I put the 3/8 underlay down, then the 1/8 ditra and the tile which is 3/8 im looking at 7/8 physical thickness + the thickness of the thinset. Which means just the materials is already 1/8 thicker than the hardwood. add thinset probably gets to 1/4 taller.

 

So with all that said, do I just drop the 3/8 thick plywood underlayment and replace it with 3/8 cement board and drop the ditra? I know the subfloor needs to be 1 1/8" thickness minimum for tile so the 3/4" with the 3/8" cement board makes that happen and the tile will be basically the same height as the hardwood. Problem is finding 3/8 cement board, I can only find 1/4" and 1/2" so ill have to do the 1/2" which will get me the same height as the plywood and ditra.

 

Problem with cement board is its supposed to be thin setted down to plywood however I know people are saying they dont do that anymore and its fine. if its only 1/4 inch taller I can probably get away with a transition piece and it wont be to noticeable.

[STEVE-O]

Toss hardi board down and use backer screws then mortar and tile over that , can easily use a transition strip

 

Now matter what if you ever go to rip it all up it’s not going to be a fun time

[cstmg8]

Remember, 1/2" hardie is actually 3/8" anyway.

 

I've done lots without bedding it in.

[Green Bastard]

When the tile was installed in my bathroom my wife's uncle just screwed the cement board to the subfloor then put the tile on top of that.

[zeitgeist57]

Same as these guys above: we tiled the only bathroom in our starter home back in 2003 with cement board screwed into our 1953 subfloor, then tiled/grout over top. I can't remember the details but a close friend who does renos/flips helped me with the steps. Then a metal transition strip to the wood floor in the hallway.

 

17 years later the house is our rental and still holding up well.

[STEVE-O]

Should have mentioned you only need to use the ditra style underlayment if you have concrete To go over not a traditional wooden subfloor.

[BIGGU]

Thanks guys, I think im going to return the ditra and go hardieboard. even through the fiberboard is taller overall its going to be a closer fit height wise to the hardwood and less work to install.

 

Steve-o you can use the Ditra on traditional subfloor but they really want you to go directly onto the subfloor. if you do that you can get tile that is much lower. I just dont want to do that because I dont want to risk damaging my subfloors if it doesn't turn out.

[STEVE-O]

Thanks guys, I think im going to return the ditra and go hardieboard. even through the fiberboard is taller overall its going to be a closer fit height wise to the hardwood and less work to install.

 

Steve-o you can use the Ditra on traditional subfloor but they really want you to go directly onto the subfloor. if you do that you can get tile that is much lower. I just dont want to do that because I dont want to risk damaging my subfloors if it doesn't turn out.

 

Yes you absolutely can but it is not needed, hardi will be just fine . I only use ditra over a slab as it works as a vapor barrier as well