Hello,

Had a few questions with regards to installing tile for a new shower I am installing, since I am finishing my basement. The basement was already plumbed for a bathroom, but it was plumbed for a tub, I am installing a shower, so I used a fiberglass pan, 34x60, already installed.

I was going to use Schluter-Kerdi Backer board on the walls for the tile.

My questions are as follows:
1. How far past the edge of the shower pan should the tiles go, is there usually a minimum? (I was thinking about 3-6 inches past the shower base)
2. Do I need to place a stud at the location of where the Kerdi board ends, and drywall starts, so the ends are nailed/screwed into a stud?
3. Do I tile right up to the joint of the kerdi board/drywall, or do my edge tiles actually end up covering that joint, so a portion of the edge tiles end up being installed on the drywall?
4. When installing the kerdi board, should it go over the shower flange, and leave about 1/4" above the lip and caulk that, or do I stop it short of the flange, and caulk the gap between the board and flange?

Thanks,
Steve

Any takers? Is this line of question in the wrong thread?

Thanks,
Steve

1. Normal distance is usually a cap tile past end of shower base.

2. Yes

3. Tile covers the joint.

4. Over edge of flange.

Chuck

Thanks, those were pretty much the answers I was expecting to have.

With regards to placing the board over the flange.

I have a small gap, maybe about 1/8" or so between the stud wall, and the shower pan at the back wall of the shower, and then the flange is thick by about another 1/8" or so. So that means I need to place about 1/4" shim to get the face of stud to be flush with the face of flange, and then if I place 1/2" kerdi board, the total wall thickness there is 3/4", while the adjoining drywall will only be 1/2"

Do I need to shim every stud in the bathroom then, so the face of drywall and face of backerboard are the same, or can I use 1/4" thick kerdi backer board? Is there a certian thickness backboard I need to use, is 1/4" to thin (do they even make 1/4" backerboard).

What would be the best way to go, so that my drywall and backerboard come out in the bathroom in the same plane/flush with each other?

Thanks,
Steve

If this is a shower stall you will have 3 walls. Shim back wall from base to ceiling and install water resistant at top.

Chuck

Yes its stall with 3 walls. But I am talking about the vertical joint between the backerboard, and the drywall that will be on the rest of the walls, outside of the shower. The shower walls will have the shim, plus backerboard, but if I do not shim the drywall everywhere else, the faces of wall will not line up properly.

That's why I was wondering, if I use 1/4" shims, and then 1/4" backerboard, that will then be flush with plain old 1/2" drywall. I was not sure if I can use 1/4" backerboard, do you need the 1/2" stuff for strength to hold the tile?

Thanks,
Steve

If you are talking about the wall I think you are talking about, the wall opposite the shower head, chisel out a 1/4" notch about 4 or 5" high of each stud so the interior surface of the shower pan is flush with the surface of the stud.

BUT, you are going to say, that will make my opening to large. Put a 1/4" filler strip on the face of the studs of the shower head wall. That at most should be 4 studs.

Each job is different, for sure, but in most cases we set the pan in a structolite or mortar base... level front to back and side to side (some manufacturer's want you to use a notch trowel and adhesive or even just plain silicone... read instructions!) and secure the base to the studs if required by the manufacturer.

Install vapor barrier to studs (use silicone or staples to adhere to studs) being sure to overlap the flange of the base.

Install cement board to within 1/8" of the shower base, and do NOT touch the base (water can wick up the wall if cement touches the base). Here, there is no need to shim the wall....cement board sticks out 1/4" past base flange. Fill the 1/8" gap between the cement board and the base with silicone if you want (vapor barrier needs to be smoothed out here).

Let all dry, install cement board leaving 1/16" - 1/8" gap between boards and tape and seal seams with appropriate thinset adhesive.

The rest is tiling work... ;)

Mark

Quote:

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Originally Posted by massplumber2008

Each job is different, for sure, but in most cases we set the pan in a structolite or mortar base....level front to back and side to side (some manufacturer's want you to use a notch trowel and adhesive or even just plain silicone...read instructions!) and secure the base to the studs if required by the manufacturer.

Install vapor barrier to studs (use silicone or staples to adhere to studs) being sure to overlap the flange of the base.

Install cement board to within 1/8" of the shower base, and do NOT touch the base (water can wick up the wall if cement touches the base). Here, there is no need to shim the wall....cement board sticks out 1/4" past base flange. Fill the 1/8" gap between the cement board and the base with silicone if you want (vapor barrier needs to be smoothed out here).

Let all dry, install cement board leaving 1/16" - 1/8" gap between boards and tape and seal seams with appropriate thinset adhesive.

The rest is tiling work...;)

Mark

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So similar to the attached sketch? Drawing is exaggerated a bit, but it is more for the idea. Place silicone though, in place of where it calls out thinset?

I Would leave gap between backer board and flange, and also gap between tile and shower pan, and I would place silicone in those gaps (not drawn on here).

Thanks,
Steve

Attachment did not show up for some reason. Was able to finally attach the sketch, its on the next page of the thread.

Lets try this one more time

I don't see the vapor barrier in your drawing... real good idea to add this (must go over the flange of the base).

Silicone goes between the base of the concrete board and the top of shower base flange. Thinset goes under the tile.

You could use thinset between the concrete board and the base flange IF you use an alkaline tape to "tape" the seam.

Be sure to keep tile 1/8" off the base itself (when finally get to tiling this)... fill in between tile and base with color matched caulk instead of grout for best result!

Make sense?

Yep. If I go with schluter kerdi backerboard, do I still need the vapor barrier? I thought that product was made to be a vapor barrier?

Thanks,
Steve

Hi Steve

Yeah, lost focus a bit there in that, most of the time, that vapor barrier is so important I tend to push pretty hard on them... ;)

Quick research on the subject says no vapor barrier needed here, but I would still make a call over to tech. support (or at least review the specs at their website) to be 100% sure for your job... can't hurt, right?

More questions, just let us know, OK?