subflooring for tile in small bathroom [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : subflooring for tile in small bathroom

01-29-2017, 08:51 AM
i currently have 1/2" ply + 1/4 ply and vinyl tile in 60x60 section of bathroom.
i want to put down 12x12 ceramic tile. joists are 16oc

If i rip up the 1/4ply and put down 1/2ply + 1/4" cement board will that be strong enough to support the tile? thanks

Sponsored Links

01-29-2017, 08:59 AM
i originally had some type of thick plastic sheets on bathroom wall. before i ripped them out i put a square in each corner and they appeared to be very square.

i'm putting up a tile wall so the underlayment is going to be 1/2 cement board. i'd like to assume that when i put up the boards that the wall will be square? Is there a best method for figuring this stuff out before putting up the wall? it seems that every 2x4 in the wall isn't perfectly flat against the next, so i'm starting to get concerned. thanks for any suggestions.

01-29-2017, 10:40 AM
Welcome, Owen. :)

Please keep all your project questions on one thread so folks can see what you're working on and what's been previously asked and answered. We can give it a more generic title any time you'd like to suggest one.

No, your subfloor is not sufficient for a ceramic tile installation.

First thing you want to do is use the Deflectolator in the dark blue bar near the top of the page to evaluate your joist structure.

If that proves to be sufficient, you have a couple choices for your subfloor.

If you find your existing subflooring is in sufficient condition to allow a wood glue bonding, you could glue-laminate a second layer of nominal half-inch plywood over what you have using a full spread of wood glue and lots of screws.

Second option would be to pretend you don't have a subfloor at all (effectively that's true) and install a layer of nominal three-quarter-inch T&G plywood as your single layer subfloor.

Third would be to remove the existing subfloor and install three-quarter-inch T&G subflooring on the joist tops. That would satisfy the requirements of all the tiling substrate manufacturers' requirements, including for your quarter-inch CBU.

As for square walls? Long straight edges and a framing square are the most common tools to determine that your stud walls are in plane and square with adjacent stud walls. You can also measure across the diagonal to ensure they are perpendicular to one another.

My opinion; worth price charged.

02-12-2017, 06:24 PM
1. what size towel do i need for installing 3x6 subway tile w/ 1/8" spacers.

Is 3/16 x 5/32 V groove the correct size?

2. will pre-mixed thin set mortar be ok to use. this was suggested in some forums.

Tile is going over CB.

02-12-2017, 07:01 PM
Is this for the shower portion of your bath project, Owen?

02-12-2017, 07:12 PM
yes it's for shower walls

Houston Remodeler
02-12-2017, 07:15 PM
Never use pre-mixed thinset inside a shower or tub area. WHen it get wet it will emulsify and turn back into goo. Then start to mold.

Use a dry powdered thinset you mix with water that costs more than $11 a bag.

Use a 1/4" square notch trowel. The tiles will suck the water too fast from the thinset if there isn't enough thinset.

03-27-2017, 01:30 PM
currently have 1/2 ply on 16center in bathroom. if im reading it correctly, ditra products recommends a minimum of 19/32 subfloor + the 1/8" ditra sheet. is that accurate?

03-27-2017, 02:17 PM
Yep, you need another 1/2" or 5/16" on the floor and then the Ditra. :tup2:

03-27-2017, 08:26 PM
your saying add 1/2" on top of the 1/2" + ditra

ditra products website says 19/32 or .59 is adequate + ditra

03-27-2017, 09:00 PM
Owen, again, please keep all your project questions on one thread. Duplicate threads with the same questions result in confusion and duplication of effort on the part of our all-volunteer staff of helpers, eh? :)

See post #3.

Not at all sure what 5/16ths" material Laz has in mind in his posts above.

11-14-2017, 10:09 AM
Can i use regular versa bond mortar mix (same as installing tile) to adhere dura rock to floor? and will a 1/4" trowel work?


11-14-2017, 10:22 AM
Owen, I strongly recommend you visit the USG Products web site ( download the Installation Guide for the Durock (I'm guessing) product you intend to use.

As with all CBUs in floor applications, you do not adhere the CBU to the subfloor with thinset mortar, you apply the thinset mortar to create a 100 percent footprint for the CBU and attach it with mechanical fasteners as required by the board manufacturer.

As you'll see in the Installation Guide, Versabond would be a suitable product for that application.

There are other requirements for the CBU installation as you will note in that Installation Guide.

That all presumes that you have done something to provide a suitable subfloor for your ceramic tile installation.

My opinion; worth price charged.

11-15-2017, 06:38 PM
thank you

Sent from my iPhone using Tapatalk

11-16-2017, 07:02 AM
Is it necessary to let the mortar dry after laying down the seams on durarock before tiling?

11-16-2017, 09:06 AM
No. You can do the seams with mesh and mortar as you tile. Is actually preferable as it reduces the chance for humps at those seams.

11-16-2017, 09:10 AM
thank you

11-21-2017, 07:51 AM
Looking for suggestions on how to abut tub tile with baseboard.
I'm guessing the easy way be to use the matching bullnose tile and run it under the white tile to tub?
I'd really prefer a 3 1/4 white baseboard but not sure how i would have the two abut? what are the preferences out there?

11-21-2017, 09:31 AM
I'm assuming when you say 3 1/4" base you're talking conventional baseboard.

I like to keep wood base, especially MDF away from tub/floor/wall intersection. It's a vulnerable area and seems to always see water some way or another.

in your case, I'd replace the white tile to floor and cut a 45 return on baseboard. One could do a 90 return as well. Either looks better than what I typically see, which is a clipped end without return.

11-21-2017, 11:05 AM
i like the illustration. is there a link that shows how to cut this? thank you.

Sent from my iPhone using Tapatalk