Installed curb tile doesn't align with slope of shower floor [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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12-13-2016, 01:53 PM
First bathroom remodel ever, be gentle! :-)

I used a KBRS Shower Slope and followed their video installation for that portion of the job. I installed an Oatey style drain. However, when I lay out my floor tile, it is a the full thickness of the drain lid lower than the top of the drain. Recognizing there will be some height added to the tile by the mortar, but I'm not convinced it will be quite as much as is needed to make it flush. The drain is screwed all the way down and can go no further. Is it a simple matter of applying thicker mortar to the tile near the drain to ensure that it is at a proper height?


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12-13-2016, 05:54 PM
Rob, I don't know how much I can help, never having used this product. I was curious enough to go to their website and watch the video. Their drain assembly appears to be recessed into base significantly more than your photo would indicate. Would there have been some mechanism for doing this?

I think a call to KRBS would be in order. No way you want to try and build up mortar to make up that difference. There's gotta be some other way.

12-13-2016, 06:23 PM
Good question about recessing the drain. The KBRS installation video talked about not recessing the drain into the subfloor which I think might have resulted in the drain throat therefore being recessed. I'll give them a call, good advice.

May I ask why building up the mortar is not a good idea? I'm not familiar with the qualities of mortar enough to understand the pitfalls of that.

Thanks again,

12-13-2016, 06:33 PM
Thinset mortar is designed for a max total depth of about a 1/4". Setting small tile on that much depth would surely be an exercise in frustration. If done in two stages, you'd have to have a extremely deft touch with your trowel to get an even application.

12-21-2016, 10:28 AM
Thanks Carbidetooth, for the help. Turned out, there was a specific model number of low profile Oatey drain that solved the problem. KBRS had that info when I called them, per your suggestion (Occam's razor and all :-)

01-03-2017, 11:55 AM
I am installing my first shower and have completed the shower floor. While working on the inside curb wall, I did not account for the slope of the shower floor, and am now faced with the dilema: do I attempt to remove the offending tile that has been mortared on, and recut and reinstall OR do I leave well enough alone and caulk the offending gap on the bottom (picture attached). My concern stems from damaging the floor tile or waterproofing that is painted on the curb during the removal process. What are your thoughts?


01-03-2017, 12:06 PM
1. What type of waterproofing was painted on?
2. Was it installed on shower walls and floor?
3. How was curb constructed?
4. How long since the offending tile was installed?

Another factor would possibly be your visual tolerance level for having that wide gap. It might be your path of least resistance.

01-03-2017, 12:06 PM
If you caulk I think the gap will still be noticeable - and annoyingly so because one end touches the floor tile, but you could put a piece of quarter round trim along the bottom. I think it would look quite nice and hide the gap.

01-03-2017, 12:16 PM
Welcome, Rob. :)

It'll help if you'll 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.

01-03-2017, 12:20 PM

1. What type of waterproofing was painted on? TEC Skill Set Yellow and Gold Indoor and Outdoor Barrier
2. Was it installed on shower walls and floor? It was brushed on with a paint brush
3. How was curb constructed? 3 stacked 2x4s then covered by Durock, waterproofing fabric, then TEC waterproof.
4. How long since the offending tile was installed? Tile was installed last night (about 20 hours)

epalmer: Good thought, unfortunately, I looked at the tile mfr (Daltile) and they don't have a quarter round tile.

01-03-2017, 12:31 PM
I've never used that TEC product, so can't speak to that specifically. In fact, I didn't know it existed!

Have you tried popping the tile? The longer you wait the more likely substrate damage will happen.

Surest integrity option would be to leave it... I couldn't in good conscience, but I'm not you, so factor that in...

01-03-2017, 12:42 PM
I did not try to pop it off, so just tried and frankly, it came off waaay too easily from my perspective. The mortar is still wet (and it wasn't 20 hours, it was more like 16, now that I think about it). That doesn't seem right to me. We used mixed TEC powder mortar for porcelain tile on the floor, but we used TEC Type 1 Mastic Premixed tile adhesive for the curb tiles simply because I didn't want to mix up a batch of powdered mortar for 5 tiles at 8pm last night. Did we use the wrong product?

01-03-2017, 12:56 PM
Ummmmm, not good. Even though they say it can be used on shower walls, I, and most all pros here, would avoid it.

Mastic has to dry, where the cement in actual mortar hydrates (cures) chemically. Very different products.

Were I you I'd get to removing all that you've set with it and cleaning it off what ever you're going to reuse.

Yep, mortar's a pain to mix, but it's what you want. I'm beginning to hate mastic, not for what it is, but for the way it's marketed. Boo, hiss, bad manufacturer, bad.

01-03-2017, 01:01 PM
Well that's a fine "how do you do!". Thanks for the feedback, lesson learned, but not too expensive of one! When we do the curb and shower walls, will we just apply mortar to the walls or will we also backbutter the tiles too?

On a related topic, what would I be able to use that product for? I now own a tub of it that I can't return, so if I can use it for something else, that'd be better than throwing it away.

01-03-2017, 01:04 PM
FWIW, mastic stays usable in a closed bucket on the shelf for typically, at least a year. You added waterproofing then slapped a porcelain tile on top of it, so essentially, it was closed off from drying fact, it could have taken months, if ever in a shower if it got lots of spray, to ever dry out and be firm. Many of them do not allow their use on larger tile, either, mostly because it would take too long for it to dry out via the grout line.

01-03-2017, 01:05 PM
I sometimes use it on backsplashes. Kept away from wet areas and big tile, it's OK, if not ideal.

Concerning back buttering; at the least, I'd burn the backs or the wall with thinset. It's a critical area and you want as close to 100% coverage at possible.