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krrose27

Kerdi/Redgard Questions

krrose27
9 years ago

Hey Everyone.

This site and a few others have been a real help in educating myself; however, I am having trouble finding some answers.

We have been working with a company to redo our bathroom and they started about a 2 week ago. We finally are doing the shower and it's been down hill since.

They redgarded the durrock the other day and that's when I completely lost faith in their knowledge. There is issues with the redgard but I've got a grasp on it. (Gaping holes, paint on the slab before prelsope, pin holes, super thing, etc. etc.)

Yesterday when one of their guys showed up to do a little more work I started questioning him. He ended up saying it was a problem for the plumber and he'd talk to the pm. So this morning I got a call that they are removing this installer and putting someone else on it.

So as of right now we are not doing anything until Monday.

As such this question may be out of line but looking at their setup I am taking a guess at their plan and want to be able to call BS on it on Monday if it is not correct.

(I understand they really shouldn't mix redgard and kerdi and plan to discuss this monday, but again I have a grasp on those issues.)

My current question is can Kerdi be used as a pan liner below a mud bed?

The reason I ask this is they have a standard clamping drain installed atm. They've yet to preslope the floor (old house had deep mud pan, and we have extended the shower) and I have this nagging feeling that they plan to place it below the mud bed and on the prelsope once it is laid.

I don't know why we would be spending the money on Kerdi to use it like any other basic liner.

(Sorry if I am confusing anyone, let me know if I can clarify anything.)

Comments (13)

  • StoneTech
    9 years ago

    If they are doing Kerdi....do ONLY Kerdi! Redgard has no place there! With Kerdi, you need to use ONLY their proprietary drain....NOT a "clamping drain." There is NO preslope needed with Kerdi as the water cannot go beyond the fabric.

    You don't even need Durock in a Kerdi shower.....regular drywall is factory recommended. When you use TWO different waterproofing materials, you run the risk of a "moisture sandwich," which is NOT good.

    I recommend you get someone conversant with SAM's (Surface Applied Membranes) and tell these guys to pound sand.....in other words....GO!

  • PRO
    Joseph Corlett, LLC
    9 years ago

    If there were a "like" button next to StoneTech's post, I would be hitting it now.

  • krrose27
    Original Author
    9 years ago

    Thank you for reaffirming that. I am in agreement. I've more or less have been able to gather that from a ton of other threads.

    I guess what I am trying to ask is "why can't you"? I understand you can't(or shouldn't) but "why not"?

    I understand Kerdi is degsined to go on top of the final mud/foam pan; however, why couldn't you use it as a pan liner on the preslope into a clamping drain?

    What would be the possible issues? Would it fail, why?

    (I am completely against it but I have a feeling I'm going to have toexplain my reasoning and "because it's not manufacture spec" may not be enough.)

  • millworkman
    9 years ago

    It's the wrong way to do it period, your paying the bill and either they do it right or they take it all out and you hire someone else who will. Remember you have to pay for it an live with it!

  • StoneTech
    9 years ago

    You could always buy a Chevy and modify it to put a Ford Motor in it.....but WHY? Go with what works.

  • MongoCT
    9 years ago

    It simply comes down to installing the material as it was designed to be installed. When you go outside the box, you;re sailing off into unchartered waters. And with unchartered waters comes an unwarranted installation.

    Clamping drains are also designed for use with certain sheet materials. The clamping action of the clamping drain could shear the thin polyester film within the Kerdi, potentially creating leaks.

    Your installers will be using the drain with an unapproved membrane (Kerdi). Why?

    Your installer will be using the Kerdi in an unapproved way. Why?

    Your installers are choosing to marry two products (RedGard and Kerdi) that are not designed to go together. Why?

    Do understand that building code specifies that the floor membrane itself needs to be sloped. It can't be put flat on the subfloor with sloped mud over it. The membrane itself has to be sloped.

    If they are doing a mud slope with a clamping drain, and they are already using RedGard on the walls, they might have better luck with the divot method.

    Some things I simply don't get. Your installers are taking fine materials and buggering them all up to make the materials less effective and to make the installation more difficult than it has to be. And in the process the way they are using the shower materials will violate any manufacturer's warranty. I'm not big on a manufacturer's warranty. But I do use materials, especially materials like membranes, in the way they were designed to be used.

    I recommend you read the RedGard installation pdf. Pay attention to gap widths allowed in the substrate (cement board) and if fabric is needed to bridge those gaps, or if the RedGard can bridge those gaps with no fabric.

    This post was edited by mongoct on Mon, May 19, 14 at 8:52

  • krrose27
    Original Author
    9 years ago

    Thank you mongo for the info.

    Will touch in later after they stop by today.

  • krrose27
    Original Author
    9 years ago

    Just a little update.

    They're pulling the durock. Ordering some additional kerdi supplies (drain & a niche).

    We are going to go full Kerdi.

    Thank you everyone for the information and help.

    I'll post some pictures as it moves forward.

    (Also Mongo thank you for "buggering". It was used in our talk today.)

    This post was edited by krrose27 on Tue, May 20, 14 at 18:40

  • PRO
    Cabot & Rowe
    9 years ago

    You can visit the Schluter web site to see some excellent videos on the installation of Kerdi to see how it is done properly. Paying special attention to the seams and inside corners.

  • StoneTech
    9 years ago

    I agree. An excellent resource. There are also numerous You Tube videos on "Kerdi Showers."

  • krrose27
    Original Author
    9 years ago

    New question. (This will be asked to the GC/Designer later today/tomorrow but I thought I'd see what you all think).

    We are doing a 12x24 FUSION Pearl Tile (http://www.happy-floors.com/brands/fusion/) in our bathroom.

    They of course recommended not using it on the floor. So we picked out a little 2x2 that matched in the show room. When is was delivered yesterday we realized it really didn't match. We went up to the show room and looked at what they had and the only decent option there was a stone mesh. We also looked elsewhere and aren't coming up with anything we are loving.

    So while doing a little reading I found a thread here in which annkathryn cut down 12x24 into 6x4. (http://ths.gardenweb.com/forums/load/bath/msg080345558263.html).

    So I've done a little more reading and from what I can tell is that you can do this but you will run into sharp/weird edges? Should this be a concern? Do you all think it is feasible/reasonable to do this?

    I was going to ask about friction but the tile is 0.62 Wet ASTM C1028 and from everything I am reading that is acceptable for a shower application. (It's more then the 2x2 we had ordered.)

  • MongoCT
    9 years ago

    I cut down larger tiles into smaller for use on shower floors quite often. I do have a few photos buried about halfway down on this Kerdi thread. A few things to be aware of, one which you already mentioned:

    1) Cut edges being sharper than the factory edges. Some tiles are cut to size at the factory after being fired, so if you have those, then matching an on-site cut to the factory edges may not be a concern. For the tiles I used in the above-linked thread, I simply eased the sharp cut edges that I created with a couple of vigorous swipes with a carborundum stone.

    2) If you have glazed tile, with the tile glaze being a contrasting/different color than the tile body. A cut edge may show for example a dark glaze on top of a light tile body color. When grouted, if the grout doesn't completely fill the joint you might be able to see the white tile body in the tile joint. The tiles I used in the link were through-body, where the surface of the tile is essentially the same color as the tile body.

    3) Tile sizes not matching. Meaning that the whole tiles are not cut perfectly in half or thirds, so the sizes vary a bit. Normally not an issue. Depends on how careful the person in the wet saw is with the cutting.

    It's not terribly critical on a shower floor though because of the compound slopes on a shower floor.

    Your best bet can happen if your tiles are through body rectified tiles. Meaning that the show surface of the tile is pretty much the same color as the tile body, and that the factory edges are cut edges made after the tile is fired versus the tiles being pressed or molded with rounded over or chamfered edges, and then the tile is fired.

    Neither is a deal breaker. Just things to be aware of depending on how particular you are.

  • krrose27
    Original Author
    9 years ago

    Mongo/Others

    Our contractor more or less said "NO" to cutting our 12x24. Says they come out to sharp and he has redone a whole floor once because of it.

    He also doesn't want to use our big 12x24s as the floor tile.He says they'll be to slippery. They have a 0.62 ASTM C1028 Wet Neolythe rating. Which from what I am reading should be high enough for a shower floor application. (http://www.happy-floors.com/images/fusion.pdf)

    He says that really doesn't matter nor does it compare to the 3x3 he wants to use that also has a 0.60 cof. He claims the grout adds traction and with the large tiles you will "hydroplane".

    I really... am just at me end. I've lost a lot of faith in them since the start of this project and probably need to find someone else in my area; however, it was hard enough finding them.