Schluter Kerdi shower system...help!

secutanudu

So I am in the middle of a complete gut and renovation of my bathroom. I am doing a custom shower and my contractor put in the Kerdi membrane yesterday. Admittedly, it was his first time using the product. He and I both watched the instruction dvd and read the manual. We installed it over hardibacker concrete board.

The instructions said repeatedly (and their phone tech told me) to use unmodified thinset to apply it (there was a whole section devoted to it), which is what we did. We used latircete megabond thinset without the latex additive, we just used water. The mortar seems to crumble when scratching it with a putty knife (or your nails for that matter). The kerdi paper peels off pretty easily and when you look at the back of the paper, the mortar doesn't appear to have adhered to it at all.

I think we followed the directions exactly. I plan to call both schluter and laticrete tomorrow to find out what went wrong. Needless to say, I am furious and frustrated. The whole schluter system cost me almost $700.

Any advice? Thanks.

__________________
Andrew

Bud Cline

WHY are you trying to peel it off? Don't do that! You're fine.

JohnFRWhipple

Let the thin set set up and listen to Bill and leave it alone. Give it three days before checking. I find a shop vac held at a 45 degree angle to the kerdi (NOT FACE ON FULL POWER!!!) will let you know if the Kerdi is set properly.

Many people mix their thin set to stiff or have a bond breaker on the substrate. All most all ways I think this is the cause of these failures.

It's good practice to wet the walls with a little mist (after their cleaned) or damp sponge and scratch the non-modified thin set into the cement board. Use Schulter's Kerdi trowel to get the right amount of thinset onto the wall. When you press the Kerdi tight to the wall you will see little faint lines of where the thinset is making contact with the kerdi and the wall. You want to see this all over. If the Kerdi is still bright orange and no trowel lines (smushed) can be see you may have had a bond breaker or very thirsty wall board.

I try for full coverage on my seams and a nice tight fit...

Also work with with smaller pieces. This gives the cement board less time to steal moisture from the thin set.

Was it very hot that day?

Ron6519

The thinset mix needs to be on the looser side. If you mix it so the ridges from a 3/8" trowel back fill a bit, it should be good. As said, this needs to get put on the walls and covered quickly.
Ron