Bathroom Project: Tiled floor and Shower

[enduring]

Hello, a new bathroom project underway. My last one was a success, thanks so much for the help on that one. The tutorial on laying wire and SLC was very helpful too.

This new shower will be in an alcove that will be built to accept a Kohler Salient cast iron pan with center drain. I will tile the walls (or hire it done) to the ceiling which are 8' high. These tiles will be porcelain 12x24. Prior to tiling I will line the walls with CBU, tape all seams with fiberglass tape and setting type joint compound, and apply 2 coats of Hydroban as a moisture barrier. I will install an exhaust fan/light in the shower ceiling area. I want to put in 80" glass shower door and mount my shower head at 80" for my tall family. There will be a pocket door on one of the ends of the shower tiled area. I am wondering how to stiffen the wall enough for the tile. I called Johnson pocket door people and they told me that they recommend a sheet of 3/4 ply before adding CBU on the pocket wall.

Questions:
1) Is the lining of the pocket wall with 3/4" ply then the CBU adequate to create a safe tiling surface?

2) If I use the 3/4" then CBU how do you deal with the edge? Where do I stop the thicker wall material? My tile selections does have a piece that can turn a corner. It is Atlas Concorde Marvel Calacatta Extra line. But I have no idea what the dimensions are to that turned edge.

3) Where do I stop the CBU and start the drywall at the periphery of the other alcove wall; outside the shower door or just inside under where the last tile will go?

4) what is a good amount of extension beyond the shower door area to bring the tile? Do you typically stop at the outer edge of the shower pan?

5) Do I use CBU on the ceiling of the untiled portion or drywall (and what kind is best)?

6) With Whatever goes on the ceiling, can I Hydroban then paint over it ? Or do I just paint?

Thanks for your attention (I don't know what this means but I love popcorn)

[Giuseppex]

Pocket doors behind showers need mud screeded to at least 3/4 thick in my opinion. I have done a few that way but not tried the cbu and ply approach. No probelms yet with the screed walls so far.

[enduring]

Giuseppex, thanks for your reply, that is good to hear. I wont be doing mud because of my lack of experience. But I think I can see how that would work.

My carpenter and I are working out a plan to put a thicker wood frame system up for the pocket door. Such as a frame that is Kregged together with the 2x4's flat. So the top and bottom rails with 3 uprights all flat, 16" oc, and Kreg screwed together. Or something like that. I have the extra inch or 2 to be creative to strengthen the wall. With this 2x4 frame I wonder if I will need the ply. Though I know that this wall will still be more flexy than 2x4 in the traditional installation.

What about painting over hydroban?

[Tool Guy - Kg]

Originally Posted by enduring

Prior to tiling I will line the walls with CBU, tape all seams with fiberglass tape.......

Alkali-resistant mesh tape, to be a little more specific.

Originally Posted by enduring

setting type joint compound,

Hopefully, you're referring to the same thinset you'll be using to set the tile.

Originally Posted by enduring

I will install an exhaust fan/light in the shower ceiling area.

Make sure it's a fan that is "wet rated" if you're going inside the footprint of the shower, as almost none of them are. Most fans are only "damp rated".

Originally Posted by enduring

1) Is the lining of the pocket wall with 3/4" ply then the CBU adequate to create a safe tiling surface?

I would completely remove the 3/4" horizontal slats that form the pocket door wall and replace it with 3/4" BCX plywood. At this point, it's not stiff enough to "cement board and tile". It's been done, and some folks have gotten away with doing so. But you indicated you have some thickness you can afford and I'd recommend putting a second layer of 3/4" over the first layer. Especially if you laminated the two layers together with white glue (full spread over entire surface with a small notched trowel) and took precautions to pre drill for screws, you'd be able to screw them tightly together and end up with a fairly stiff wall.

Originally Posted by enduring

3) Where do I stop the CBU and start the drywall at the periphery of the other alcove wall; outside the shower door or just inside under where the last tile will go?

Typically, you'll stop the cement board just inside of where the tile will stop. If you need to stop it outside the tile, you can use drywall joint compound over the surface of the cement board to make it smooth enough to paint.

Originally Posted by enduring

4) what is a good amount of extension beyond the shower door area to bring the tile? Do you typically stop at the outer edge of the shower pan?

I'd run the tile out at least a couple inches past the outer edge of the pan, as the vertical section where the pan meets the wall sees a fair amount of moisture and is a prime spot for moisture damage to plain drywall.

Originally Posted by enduring

5) Do I use CBU on the ceiling of the untiled portion or drywall (and what kind is best)?

Drywall is fine for a ceiling of a regular (non-steam) shower. Besides, if you really want cement board up there (overkill, but okay), you'll need 12"O.C. support, which you are unlikely to have. On that note, how far apart are your ceiling joists?

Originally Posted by enduring

6) With Whatever goes on the ceiling, can I Hydroban then paint over it ? Or do I just paint?

Just paint.

[precison_tile]

Here is an option:
I had the same situation recently, pocket door was one wall of the shower...
I built a pony stud wall from 2x4's between the pocket door frame and the shower. This gave me a buffer to the door, allowed me to install backing for the bench seat and grab bars and it only used 4.5" of space.

[JoeBoxer]

I recently did similar to Pete, and put up a normal 2x4 wall between the shower and the Johnson pocket door. This allowed me space for plumbing, niches, and a confident place to mount the heavy glass door.

I used redgard as my vapor barrier floor to ceiling.

For ceiling, I used GP DenseArmor+ which is a fiberglass impregnated gypsum drywall with a fibreglass skin instead of paper. It's heavier, but I was planning to have a lot of water sprayed into the ceiling while I shower with the powerful body jets. For paint, I had some left over exterior grade white paint ...

So far, is rock solid.

Look below for pics.

[Pete1972]

And same here as Pete and Joe; I framed in a pocket door wall next to a 2x4 studded wall that would have been difficult to move. It makes for thicker door jambs but I can live with that. The existing 2x4 wall was load bearing and would have required rerouting some things so it would have been a real headache to rework to incorporate the pocket door.

[pgc555]

Originally Posted by Barbara

My last one was a success, thanks so much for the help on that one. The tutorial on laying wire and SLC was very helpful too.

What tutorial are you talking about????

[dhagin]

She may be referring to the threads in the Liberry?

[enduring]

Oh My, I have been away and just now checking this post. Thank you all for the very thoughtful feedback!

We are slowly progressing, and the walls are just installed. But there might be some wiggle room to work in some of these suggestions.

Tool Guy, great information thank you so much for all of your details. the numbers relate to your listed entry items (not mine in the OP):

1&2) yes, I will use the thinset and alkali-resistant mesh tape as you suggested.

3) My fan will be a vent with remote inline fan. So the only thing in the shower will be the bulb/vent. The Fantech techical support is who helped me design the fan setup to match their dual location kit, that is wet rated but too big for my smaller bathroom. I assume the vent/light he specified for me are the same as in the dual kits but I am not positive. I did tell him I was going to put one of the vents in the shower. Their online info on the dual vent kit says they are wet rated. I wont have body jets, so hopefully not a lot of flying water. There will be a hand held spray and that water could get the ceiling on a rare occasion.

4) We wont have the preformed pocket door kit. The framing it is being build into a 2x6 wall space and 2x4 laid on their sides with a rabbeted 3/4 edge on each side taken out to accommodate the 3/4 ply, so it can lay flush with the stud wall. Then the CBU will be flush with the drywall. I think this sounds like a strong wall. What do you think?

5) thanks, I will plan the CBU to stop just under the outer edge of the last tile location.

6) The plan now is to stop my pocket door wall tile at the edge of the pan. The shower door will be stationary at that location. The other end near the door opening and shower head will be wrapped around this plumbed wall and around to the other side where there will be a cabinet housing my W/D stacked set. So this will protect from the water that you mention. I don't think I need to be concerned with the back end of the shower because it will be sealed glass. Am I right in thinking this?

7) Thanks for the CBU on ceiling information. I will just do the drywall or what ever and skip the CBU.
You have been a great help with your detailed information.

precison_tile, that is a great idea with the extra wall. See above in item #4 to Tool Guy, for my carpenter's plan.

JoeBoxer, I will look into that wall material for the ceiling, GP DenseArmor+, thanks for the information!

Pete1972, sounds like the 2x4 stud wall next to the pocket kit is the way to go if I ever do this again

pgc555 & dhagin, yup, in the Liberry! Very helpful

[enduring]

New question about the floor and 12x24 tile plan. I would like to tile with 12x24 porcelain. I have a deflection of L / 544. The diagonal boards are pictured below and are 3/4 thick, nailed to the joist. I will be using self leveling compound with warming wires over my subfloor installation. Then Ditra and tile. My concern is the type & thickness of plywood I should use as my subfloor, to go over this initial layer in the pic below.

My plan is for plywood laid over the diagonals, perpendicular to the joist. 1/8" expansion joints between pieces of ply. Screwed down 6" oc throughout the floor, into the diagonal pieces only, avoiding the joist. Caulking the expansion joints before the warming wire, primer, and SLC.

1) will a single layer of 3/4 ply be enough of a layer for my 12x24 tile plan? This will total 1.5 inches of wood, over the joist, a layer of regular wood and a layer of ply.

2) does the ply need to be exterior grade?

3) there is a T&G ply that my carpenter said he was going to get, is that ok or should I nix that plan and ask for something else?

4) any other thoughts or problems seen in my plan?

5) I had planned on installing the 12x24 floor tiles myself. I am capable of doing these types of things but I am getting older and need the help of others to do lifting of the SLC and the pour. I can direct. I wonder if I will have trouble setting the tiles flat. I have seen the leveling systems that are out there but the expense might be prohibitive. Of course I have no idea what it would cost to have a tiler install it for me. But I might go that route. Any thoughts on this last item #5 would be helpful.

[Lou_MA]

Hi Barbara -

I'd feel comfortable with 1/2" exterior-grade, square-edge (i.e. non tongue and groove) plywood with no face grade less than "C". If you have room for 3/4" though, whether tongue and groove or not, all the better.

I'd recommend fastening every 4" on the perimeter, but every 6" is fine in the field. Use fasteners that are long enough to fully penetrate both the plywood and planks, but with minimal penetration into the floor joists.

Re: #5, the SLC pour should get you a flat, level surface for setting. A system like LASH from Home Depot may help in setting though.

[aboynamedmoose]

I ordered the pocket door kit from Johnson Hardware with the metal studs. I sandwhiched 1/2 plywood to that whole wall with liquid nails and screws on ALL the studs. For the shower entrance I built out some 2x4's all the way to the ceiling for a place for the shower bar curtain and allow the curtain to go inside the shower some to prevent water spray from getting out. Then on top of the 1/2" plywood inside the shower on the pocket door wall, I glued and screwed 3/4" plywood on top of the 1/2" plywood. I put a gazillion screws in it and even put about 40 bolts all through the wood and tightened them on the other side to prevent screw jacking. I waited about a day then removed all the bolts, nuts and washers. On top of the 2 layers of plywood I used Ga Pacific's Denseshield and I'll use Kerdi on top of that. My sheetrock guy said it was the sturdiest construction he'd ever seen, not to brag but it's rock solid. The only problem I've had thus far is I had to make my own split jambs for the pocket door because the side with the plywood is thicker than the side with just sheetrock. Not too much of a problem, just ripped some 1by on the table saw and primed and painted them. I did the same thing in my laundry room with just the 1/2" plywood and sheetrock on top of that.

[Tool Guy - Kg]

Hi Barbara,

1) Especially since those boards are on a diagonal, I'd use 5/8" plywood at a minimum.

2) The plywood itself isn't exterior rated. Rather, the GLUE is exterior rated. It means that this plywood can get wet and the GLUE won't degrade in the presence of moisture. The wood itself that makes up the plys of this plywood is not exterior rated...it is typically southern yellow pine and I can assure you that it would rot if left unprotected outdoors or in the presence of continual moisture.

(What gets confusing is that sometimes folks accidentally think we're trying to get them to use a pressure treated plywood (because this plywood is specifically meant for exterior use) which is NOT what you want. That's a different animal altogether and doesn't play well with tile assemblies.)

3) If your carpenter is planning on purchasing something like BCX plywood, that would be great. In this example of "BCX", the "B" stands for the grade of plywood on the top surface. The surfaces are graded from A (best looking) to D (pretty rough with lots of knots and cracks). The "C" in this sample stands for the grade on the bottom side. The "X" stands for exterior glue. But not all lumberyards and big box stores use this system. Sometimes it won't specify the grades. If you're clear to them that you need: at least a "C" grade or better on both faces, plugged and sanded, with an exterior rated glue, you're good to go.

[Lakee911]

Very nice framing work, Andy!