OH NO! Leak in new tile shower! [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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08-04-2004, 07:41 PM
I don't know how, but it seems I have a leak and I don't know how to fix it. I built a tile shower using 1/2" cement board on studs, used Kerdi for all seams, corners, the floor and a minimum 6" up the sides, and over the curb. Thankfully (I think) the wall that holds my plumbing is still exposed from the other side and I can see that there is a water problem at the floor below the plumbing. I have checked and triple checked the copper and there is no leak there, but a bit of condensation. Nobody used the shower for 2 days and so it dried up a bit (though the sill plate was still quite damp). Tonight, after two showers, it's wet again. It looks exactly like water is seeping through the joint between the floor and the wall. How could this be? More importantly, WHAT DO I DO TO FIX IT??????

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08-04-2004, 07:47 PM
You shouldn't have condensation,could be a tiny leak there,but you could get a plumbers inflatable diaphram to put in drain pipe,inflate and put 1" of water in shower floor,mark water level and check after a day and see it it goes down.Also check the plumbing with the shower on to see if it's leaking there while water is running.

08-04-2004, 08:02 PM
Thanks for the hint about stopping up the drain. I'll try that tomorrow. I did watch the plumbing when the kids were in the shower and there is no leak there that I can see. Condensation was on the cold copper pipe on a really hot day; I had hoped that was the only trouble. No condensation tonight.

08-04-2004, 08:25 PM
did you waterproof all the way up the wall? is water runniing down the wall behind the membrane? using Kerdi on the wall you need to go all the way up!!(not just 6")

08-04-2004, 08:57 PM
Hi Amy,
Eric's right, Kerdi does need to go all the way up. Do you have your Kerdi pan liner on top of the cement board where it meets up with the wall? Water gets through the grout & into the cement board. If your Kerdi doesn't go all the way up there is no way to funnel that water inside the pan & out to the drain. Did you use the Kerdi drain?

08-06-2004, 06:53 AM
Eric & Tom, no I did not put Kerdi all the way up on the vertical walls. There was a lot of debate about it here whether I should or not and in the end I didn't. Lots of pros don't and lots of pros do -- next time I would use it all the way, but for now this is what I have. And, no I did not use the Kerdi drain. I found the same thing for only $15 instead of $50 and have no trouble there whatsoever. Your answers didn't give me any advice on how to fix the problem, just how to do the whole D* job over and I'm not doing that.

Actually, in the end, the first response I got for my inquiry seems to be the right one: there IS indeed a very small leak in my copper that I didn't find before. As much as I hate doing over that copper joint, it's a heck of a lot better than redoing the entire shower! Thank goodness!

08-06-2004, 08:04 AM
The differance is with Kerdi installed in a thin set method it MUST go all the way up the wall.If A conventional pan is used under the mud bed it is then turned up the wall (behind the wall board) only needs to go up 3" above the curb or flood plane.As you installed it you have a problem! You might get away with removing the first row or two of tile and bottom 12" of wall board.Install the membrane to the studs then replace the bottom 12" .

dave on his knees
08-06-2004, 10:04 AM
Hmmmmm: I would love to buy $15 kerdi drains, instead of 89 bucks. Sounds like this is a unique use of kerdi. Kerdi used to make a traditional pan. Did you use a two part drain and clamp the kerdi between or just thin set it to the top of drain flange. Can't believe it will last more than a year. Good luck

08-07-2004, 06:41 AM
The drain I bought was indeed 2 part and the s/s seive part is removable after installation for cleanout and yes the Kerdi is clamped between. It is exactly the same construction (as in how to put it together) as the Kerdi drain but the drain on top is round instead of square which made no difference to me. I really couldn't see putting out the extra $ for the Kerdi drain. I couldn't use the shower pan kits because everything is an odd size.

In a year email me at alexbiz at on dot aibn dot com and I'll let you know if it's still dry. I sure hope to God it will be and frankly I don't think it will be a problem. I was completely flubbered when I saw the dampness, but it is now fixed and all is well.

08-07-2004, 06:59 AM
We'll hope for the best, Amy, and your shower should have no problem lasting a year - that's not really much of a test for a shower.

One problem I see is still that drain. The Kerdi drain is not a clamping drain and the Kerdi is not made to be clamped in such a drain. The actual Kerdi drain system requires the Kerdi pan to be attached to the special surface of the drain with thinset just as it is to the rest of the floor and walls.

I'm curious how you thinset the Kerdi to the floor an still were able to clamp it into a clamping drain. And did you then tile directly to the Kerdi, or did you make a mud bed over it as in a standard membrane-type installation?

The two pan systems are substantially different in construction and I'm wondering how you merged the two.

Enquiring minds alla time wanna know. :)

08-08-2004, 09:49 PM

I don't know that I can answer your question very well without photos (which I only took film photos no digital and the film isn't developed yet) but I will try.

I didn't use Kerdi anything except for the orange Kerdi waterproofing membrane. We are on an extremely tight budget and a VERY small bathroom. The shower could not be a standard size so I didn't use a pan, just the membrane. I was assured this was OK by several sources. So, here is what I did:

I laid down cement board on all of the floor and on all the vertical walls. I made a sloped shower floor on top of that with cement and actually went steeper than the 1/4" per foot, more like 1/2", which doesn't seem to be uncomfortable at all. Part of the drain was screwed in place at this time. This was an adapter that could connect to 3" or 2 1/2" ABS drain pipe below the floor. After the cement dried, I put the Kerdi membrane in place using tile mortar. To install the membrane around the drain, I cut a 20" square of Kerdi, cut an "X" in the middle for the drain, and slipped it onto the underside of the next piece of the drain which screwed into the lower drain piece. The threaded portion was quite long, about 3" or so if I remember correctly; I assume it could be used for height adjustment, but I was lucky and could screw it right down tightly. After that piece of Kerdi was in, I finished the rest of the floor (and part way up the walls) coming as close to the drain as reasonably workable, so in the middle of the shower floor I basically have a double membrane.

Putting in the tile on top of that was a breeze, except that I foolishly decided to custom cut a whole bunch of 8 1/2" tiles to get a cool Aztec/Mexican type look (with tiles I already had enough of to do the entire bathroom floor in eventually). I say foolishly, because it took me an hour just to come up with a pattern and another 4 or 5 hours to put it all down. However, it is totally awesome looking and it was done on the extreme cheap! I didn't have to buy a single tile. I was going to do the floor in mosaics, but when I found them to be $4/ft, decided to make do with what tile I had on hand.

All in all, it is a decent job, IMHO, for an amateur, for cheap and in a small bathroom with limited options. BTW, we were going to splurge and install a frameless glass wall on one side, but after trying the shower out, we decided we wanted to be able to open the "wall" after all and opted for a very cool looking plastic accordion closet door with translucent panels from Home Depot! Currently I am trying to figure out how to make a curved track for it. Now my husband says he wants a shower in every bedroom when we build a new house! Yikes!

08-09-2004, 06:05 AM
Amy, before you go charging off to build any more showers using Kerdi, please visit their website www.schluter.com . I'm not saying that your shower will leak. I'm saying that Schluter won't say it won't.

OTOH, you may have found a new way to use their product.

Kirk Downey
08-09-2004, 06:18 AM
Amy -

How did you attach the 20 inch piece to the kerdi below it?

Kirk out

08-09-2004, 07:50 PM
Kirk, I put the 20" piece down first and then put thinset on it before placing the remaining pieces over it. Same idea as the 2" overlap needed if the Kerdi isn't the right size.

Bob, I found the schulter site and used a lot of their info to "McGuiver" what I ended up with. We are a household of "making things work when they really shouldn't".