Why does drywall work in a Kerdi Shower?

Discussion in 'Shower & Bathtub Forum & Blog' started by jadnashua, Jan 26, 2014.

  1. Vegas_sparky

    Vegas_sparky Digital Billy

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    I used Hardi on all the wet side walls of my shower. Green board is on the dry side of the same walls. I covered the Hardi with Regard, so mines still shit anyways.

    Can someone pass me the popcorn please?
     
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    It's not like they don't tell you this upfront - IF you look at the company's website, it's right there on the first page. The reason for an authorized dealer is that you have a chance of someone there being able to guide you in the proper use of the material...just like when you buy a grey market item (a camera, watch, etc.) the company, I don't care if it is Nikon, Cannon, Rolex, etc...they will not warranty the item.
     
    Last edited by a moderator: Jan 28, 2014
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    The only company that has a tested and approved method of building a shower with drywall as the substrate is Schluter with Kerdi. NO other methods have been tested and approved. Depending on how long and how big a leak that might occur, neither Hardie nor drywall may be enough...the underlying wood would rot out. Drywall doesn't immediately fail, you have to soak it. If there's enough to soak it, your structure is at risk.

    How many people build their house to be tolerant of a pipe leak? Nobody. Think of all of the water pipes in the walls and ceilings, beneath kitchen and bathroom sinks, toilets, etc. You test that as well before you close it up and you don't waterproof the walls and ceiling around where they run, either.

    If you cannot tolerate the possibility that something could break, build it a different way and protect yourself...but, a properly built Kerdi shower does not leak, now, or in the future. Any shower, improperly built can lead to structure damage and necessitate a tearout and rebuild.
     
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Custom Building Products has specific instructions on how to use RedGard as a waterproofing layer in a shower. If you follow their instructions carefully and have good workmanship, it can work. Personally, I prefer a sheet membrane. RedGard applied too thin or too thick or with a pinhole is less than ideal.
     
  5. DougB

    DougB Member

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    Hey man - it's not a camera, not a car, it's some damn fabric that comes off a roller in a factory.

    So I'm supposed to go to a web site? A warranty is a warranty. If it's installed wrong, then it's on me.

    However, if I have installed the product many times, I still have to buy it from an autorized dealer to get the warranty? - which I assume nobody has ever met their spec - thus they have yet to pay a single claim. The only way for the product to fail is if the material is deffective.

    It's a scam Mr Red Sneaker!
     
  6. DougB

    DougB Member

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    I considered it with the three showers I have built. I considered that there is a possibility that perhaps the shower arm (threaded into the drop ear ell) could leak, same for tub spout connection, or a mixing valve. Cement board won't be a problem. Also I was fortunate that I could put an access panel behind the shower valves.
     
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    If the leak happens long enough before you notice it, you'll have wood rot, and probably damage to the ceilings below. The ceilings below will probably be the first you notice it if it doesn't leak out onto the floor of that room. And, that does not mean you'd have a failure in the wall assembly...most of it would run down to the floor, and in between, there's a chance it would evaporate...drywall sitting in water damages it faster than a bit of spray while you're actually showering.
     
  8. DougB

    DougB Member

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    Look - I don't question the effectiveness of Kerdi. I'm sure it's a quality product.

    The rub is that there are products (like cement board) that are inherently moisture resistant - that cost very little more than drywall - which has no moisture resistance. So you sorta have an extra level of insurance - risk advoidance.

    You want to take the risk - fine. But for me, the 'ease' of drywall is not worth my percieved risk.
     
  9. eurob

    eurob master tile and stone installer

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    Yeap. -- combined with other threads on the same subject ---> what a waste of time < ---- .
     
  10. dhagin

    dhagin builder:anti-builder

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    Regarding this site being frequented by DIYers- I agree. These days, anyone with a computer or phone can access any of this info and learn from it. Hopefully, the main thing they leave with is this:

    Always follow the local building codes & laws, and the manufacturers installation instructions with whatever product you use. If there's a conflict between any of these - and there frequently is - ask or hire a pro to sort it out for you.

    At least some of us are Pro's here and have been in business for decades. Some pro's maintain their edge through continuing education with the manufacturers, local code authorites, forums like this, etc... Most times, we can help folks sort the wheat from the chaff... but not always. The other thing folks should take away is that many here have their own opinions of things formed through direct experience over the course of many years or decades, and that each opinion may be different from others' opinions, AND valid as well. This last part is often the most difficult to grasp, yet is most important to remember. :)
     
  11. eurob

    eurob master tile and stone installer

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    The condensed answer to the Op thread is - Kerdi is providing a reliable , efficient and constant protection against water in liquid or vapor state , regardless of the approved substrate.--

    The substrate is in question here , not Kerdi. Experience and other technical documentations say drywall is NOT to be use in a wet area.

    It is just to easy -- the word easy is like a plague -- to rely on other trades for the safety of your tiled shower or wet area and say I am protected because I installed the Kerdi.

    Properly build conditions exist only when you monitor the build constantly, which is not possible most of the time.
     
  12. eurob

    eurob master tile and stone installer

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    I guess John , is like only looking at one mfg recommendation, without considering the other ones.

    Selling a high priced membrane over the cheapest product -- as substrate -- is the " winning " combination!:rolleyes:
     
  13. jim mills

    jim mills New Member

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    I still beg the question: If I install Kerdi over CMU, and the shower develops a leak, what have I gained by using the CMU? I'm not necessarily on the side of using drywall, I am just curious.
     
  14. loudgonzo

    loudgonzo New Member

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    The way I'm looking at it is if my valve leaks, and I realize this due to a puddle on the dry/opposite side of shower, I can access the leak from the back side and repair it, the hardi will have gotten wet/damp, but could still be OK after it drys, where as if the sheetrock got wet, it's more likely that it is damaged beyond repair and require complete teardown tile and all.

    leo
     
  15. eurob

    eurob master tile and stone installer

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    No debonding or major dammage to the integrity of the assembly .

    If debonding at the connection of the membrane with the CBU happens, then there is really no point in using the membrane ! A question to be asked to Sch.Tec.Dep. if curious.

    Dammage due to a faulty valve or etc. can be more costly than the cost of the CBU-- read difference in between--.
     
  16. loudgonzo

    loudgonzo New Member

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    Debonding of membrane to substrate is a different issue not discussed in this thread. I'm actually waiting for input on this very topic at this thread

    http://www.terrylove.com/forums/showthread.php?54202-Inspection-Check-List-for-Kerdi-Shower-Builds&p=407181&viewfull=1#post407181

    A faulty valve or a bad connection is just that, but the point I'm asking is that using cbu can mitigate OTHER problems that drywall can't.
     
  17. eurob

    eurob master tile and stone installer

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    Drywall will be dammaged beyond the point of safety for the assembly.

    CBU will keep the integrity even if fully soaked, which probably will not happen without visible signs or leaks.
     
  18. dhagin

    dhagin builder:anti-builder

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    Don't get me wrong fellas, I think backer board under Kerdi is a fine idea - AND, backer board is an approved substrate by the manufacturer, as are many other options. Don't tell anyone, but I've done it myself. Backers like Permabase/Dalbase install similar to drywall and don't cost that much more if you're inclined to go that route. I got no problem with that. :)

    Carry on. :)
     
  19. jim mills

    jim mills New Member

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    All good answers as to why use CMU as opposed to drywall. Interesting that it is so promoted by Schluter & JB forum. I see my local Home Depot now carries
    Schluter products. I see that as a negative towards the company & their products. The DIY'ers will ruin their reputation IMO. Interesting fact that in Europe, modified Mortars are used to seam Kerdi.
     
  20. DonL

    DonL Jack of all trades Master of one

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    You guys Crack me up.

    This is the kind of backing to have in the shower.

    Crack_.jpg


    Better when Wet.
     
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