Kerdi gone wrong - or perhaps my Schluter is slipping!

16 years ago

This site is impressive - I've gleaned massive info that's been invaluable - THANK YOU!

Wrapping up old house remodel and engaged couple of carpenters that have done a really good job, however, having issue with shower tiling and would appreciate feedback.

Purchased the Schluter Kerdi shower base kit. Shower approx 36x42. Used the cheap ceramic AO wall tiles from Lowes(6x8) and the AO glazed ceramic 2x2 tiles - for the floor.

I didn't research how to use the Kerdi system and have no experience tiling, however, have been impressed with my carpenters' skills and after they opened the kit I inquired if they felt OK with it and they replied it was a quality system - although they'd never used before. OK .. so now I realize big mistake on my part.

Long to short - the shower is completely tiled. Today they tell me the base allows too much give and the grout is breaking between the 2x2 tiles. There is an area they replaced last week and another they replaced today. These are areas approx 6x6 inches. They think it will be OK but are telling me could be a problem in the future.

They're explaining that wherever the membrane is not adhering to the tiles - the grout is breaking.

They're letting the grout dry and returning next week to check it - then sealing.

Did I get them an overly complicated system? Where do you suppose we went wrong and any advice at this point?

Appreciate thoughts and advice !!

Featured Answer

MongoCT

16 years ago

A couple of issues have already been addressed. If the subfloor was inadequate, it should have been beefed up prior to setting the Kerdi base.

Other than that, it's pretty much installer error.

The Kerdi system is pretty much bullet-proof if you follow the instructions.

If the base is flexing, it's due to an inadequate subfloor, an improperly set base (no thinset, wrong thinset), if the membrane isn't adhering to the sloped top of the tray again it's installer error (wrong thinset, operator error, etc).

Do you know what specific adhesive they used to adhere the membrane to the base, and what specific adhesive they used to adhere the tile to the membrane? Mastic? Thinset? Premixed or powdered? Modified or non-modified? Brand name?

I highly recommend calling Schluter's tech line. They're very helpful and if it's a Schluter problem, they're quite willing to fall on the sword and accept responsibility. Even when it's installer error they help out.

Mongo

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Comments (9)

Stacey Collins
16 years ago
You might want to try posting this over at the John Bridge tile forum. There are lots and lots of Schluter/Kerdi experts over there who might reply more quickly, although you will likely get good answers here too.
pepperidge_farm
16 years ago
John Bridge is a great resource, definitely tap into their experience over there.

In the meantime, here are a few thoughts:
Is the floor structure under the base firm, deflection ok for tile? Is the floor under the base flat- not just level- if you may imagine that irregularities in the floor would certainly give movement where none belongs? Have you had a chance to read the installation instructions and watch the video and go over with them how they installed it?

And of course, Schluter is very helpful on the phone- give them a call.

FWIW, I installed the shower system after painstakingly getting our sub-floor up to snuff, used self-leveling cement to get it flat (it was sooo not even close) and level. Our base is 42"sq. We used pebble, so there is a fair amount of grout- we have no problems about 6 months out.
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bill_vincent
16 years ago
One thing lonepine left out that was in the email I received is that it's not known whether or not they overlapped the sheets of Kerdi as it went in.

Kinda makes everything else moot.
lonepine711
Original Author
16 years ago
thanks everybody!! appreciate the info and trying to hook up the carpenter with someone to chat with - is on new construction - but as Bill notes - i'm not thinking membrane was overlapped and I don't know other questions/answers but at least have directions and resources to tap into. Truly, you guys are the best for taking your time to share ideas on here. THANKS AGAIN
lonepine711
Original Author
16 years ago
thanks everybody!! appreciate the info and trying to hook up the carpenter with someone to chat with - is on new construction - but as Bill notes - i'm not thinking membrane was overlapped and I don't know other questions/answers but at least have directions and resources to tap into. Truly, you guys are the best for taking your time to share ideas on here. THANKS AGAIN
MongoCT
16 years ago
Not overlapping the membrane. Good lord, this ain't rocket science. And I know because I used to be rocket scientist!

Schluter, maybe more than any other manufacturer, has readily available guidance on how to install their product.

Not overlapping a waterproof membrane it too sad to contemplate. Not reading instructions or watching an installation DVD/video prior to using a product for the first time, again, pathetic.

It's a fine product, sorry to hear that yours got messed up.
PRO
O. Tile
11 years ago
We have done around 50 or so Kerdi showers, and I would guess the membrane de-laminated from the foam pan. I've seen it happen on one of ours, I think it was from stepping on the pan before the unmodified thinset had cured. It takes a bit longer for the thinset to cure between the kerdi and foam vs. kerdi and deck mud, especially since its built up a little bit with the 1/4" trowel. We always run our hands over the kerdi before we install the tile, so that we can feel if any de-lamination has occured. It's an easy fix at that point, just cut out the de-laminated section and re-install with a 2" overlap and your good. If there's tile on it, you pretty much need to take all the tile and kerdi off, and start over.
millworkman
11 years ago
Hopefully they figured it out O. Tile as this was 5 1/2 years ago now.........