Kerdi Shower leak test Fail

[Amatuer2015]

I put in a kerdi shower kit and followed the directions to a T. Doing my leak test and 3 hrs in and I have a leak coming from under the curb. Cant see anything from underneath and cant find where it is leaking from. Any thoughts?

[cx]

Welcome, Sam.

My only thought is that you'll at least hafta show us some photos of your installation, during and finished, and even then it's not real likely we'll be able to see what you can't. But we'll certainly try.

Use the paper-clip icon above the Reply dialog box to attach photos from storage on your computer.

My opinion; worth price charged.

[Houston Remodeler]

Pics will help, at least 4, one in each direction.

How long did you wait between installing the last piece of kerdi and the flood test water being added ?

[Tiger Mountain Tile Inc]

Welcome Sam and thanks for checking out the forum. No matter how much is sucks now you'll be glad that you know it leaks now as opposed to after it's all tiled.

Did you use the preformed corners and are they all installed tight in the corner?

[Amatuer2015]

I did use the preformed corners when I installed the shower system, trying to figure out how to post pics. I waited 48 hrs after completing before I attempted the water flood test. Yes it sucks now but I would rather know now than to find it after it has ruined my floor and I have mold, that would not be good. I did speak to schluter this AM and she recommended that I take the corner seal out and re accomplish it.

[Amatuer2015]

I forgot to mention when I got up at 430 this AM the leak under the curb was dry but when I went downstairs and checked underneath there was water at one corner, so I believe that corned is bad and I am going to reaccomplish it after I remove what is there. Hopefully that works.

[Houston Remodeler]

Got a pic of the suspicious corner ?

[jadnashua]

Probably the biggest sources of leaks is related to one of five things: improper mix on the thinset, letting things dry out before embedding, excess thinset, improper embedding of the fleece, or an actual pinhole. While the membrane is fairly tough, and once covered in tile, pretty much bullet proof, prior to that, you can poke a hole in it.

If you're using the corners, you should get at least the minimum overlap. If you could isolate the actual point of the leak, a dab of KerdiFix may solve it without tearing things apart. Tearing off Kerdi will destroy the fleece, and you can't then put it back. Thinset does NOT stick to the membrane, it works by curing around the fleece fibers, so the thinset must be fluid enough to do that without excessive buildup and the fleece must still be intact.

[Amatuer2015]

Thanks for the advice I still cant get the pics to work. How do I remove the mortar that was under the corner pieces without tearing the membrane? I have removed the corner pieces and will be putting new ones down. Just need to get rid of the mortar and it was very wet under that corner, so I am pretty sure that was the source. Gonna let it set for a day and dry out then remove mortar and reaccomplish. Any thoughts on removal of mortar?

[Houston Remodeler]

My first choice would be to rub the area with the edge of a margin trowel.

Whatever you do, the sooner you do it the better.

[jadnashua]

FWIW, if you were able to pull off the corners, I'm not sure what kind of bond you actually had there! Again, the way mortar holds two sheets of Kerdi together is by flowing while embedding the stuff around the fleece's fibers. It's then mechanically locked in place as the mortar cures. Compared to how mortar 'sticks' to a tile, the bond is more like that on steroids because there are so many nooks and crannies for it to wrap itself around. But, the fibers are a lot weaker than the cement crystals, so the fleece looses verses the mortar.

You said you waited 48-hours before the flood test...how long has it been now? If you put a straight edge in the corner, how much thinset buildup is there? It really should not be much at all. It's the interference of the fleece on the two sheets that stop the water wicking through between the two...the two sheets need to be close together, not standing apart with a lot of thinset between them.