Why does drywall work in a Kerdi Shower?

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

  1. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    A failing shower is one that leaks...there is no evidence that it is leaking. If that area is where the majority of the spray hits, it may just be that that tile is saturated, which is no reliable indication that there is a leak anywhere. Not all tile is equal, especially with natural stone.
  2. eurob

    eurob In the trades

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    Not all waterproofing membranes are created equal , especially a sheet membrane -- Kerdi -- . Different rates of absorption and combine with the unmod mortar -- another thirsty one when dry -- , the drying time is ....like natural stone . Add a sealer on top of it , water will just accumulate .

    If leaks are the only thing that matter in a properly build shower , then I think the mirror is needed...........
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    The Kerdi is waterproof. If that tile is hit by the concentrated shower spray on a regular basis, the tile itself could become saturated. If this were say a conventional shower with cbu behind it, it would wick water more, and a larger area would be wet. Some stone absorbs a fair amount of water, and it can take it weeks to dry out. The choice of the tile may be suspect, but it has nothing to do with whether the shower is defective from a functional viewpoint. All the membrane does is prevent moisture from getting behind it...what you put on top of it can get wet. With a dense porcelain, the tile would not change color. If the showerhead were moved a bit, that one may not get wet. It does not indicate a leak in the shower with the information provided.
  4. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

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    I wonder if this is why spot setting tile is not allowed.

    Post(s) deleted by John Whipple
    Last edited: Mar 15, 2014
  5. eurob

    eurob In the trades

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  6. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

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  7. Vegas_sparky

    Vegas_sparky Eat kitty

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    Well good morning to you too, a-hole. LOL
  8. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

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  9. pete c

    pete c New Member

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    Good to see the battle is still alive!!!!

    As you may recall, I wandered into this forum months ago after the horse was already out of the barn, so to speak.

    i had just spent a good deal of time and money, installing a drywall/kerdi walk in shower. I did this after being sold on the idea by the tile store salesman. As iIput up the kerdi, I realized that i might be in trouble. Being a DIY homeowner and not a tradesman, my application technique was questionable. That is when i came in here looking for advice. John told me to cut my losses and rip it out. i probably should have listened. i ended up taking some of his advice and did an ardex 8+9 application over the kerdi. good stuff that ardex and wayyyyyyyyyyy cheaper/easier to apply than kerdi.

    i am now in the finishing stages of tiling. i am keeping my fingers crossed that i will be OK, but, looking back on it, it's a no brainer. ardex over CB is the way to go. much cheaper, easier to do AND if, somewhere there is a breach and water does get through in small amounts, it may be just fine, especially if there is any sort of air flow at all.

    i have just one question. why use a drywall/kerdi system over CB ardex? it is much more expensive and if it fails, even slightly, it will turn to shit in short order, whereas the CB/ardex may be just fine.

    OK, I have one other question. why didn't i find this thread before i bought the kerdi?
  10. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

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    Post(s) deleted by John Whipple
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  11. pete c

    pete c New Member

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    at best, material cost is a wash. i think the kerdi is more, personally. as for speed of application, i guess drywall night go up a bit quicker, but, not much. with the kerdi application, i have found out the hard way that you better know what the hell you are doing. ardex? mix and roll. an f-ing caveman could do it.

    advantage, ardex, especially if you are an amateur. and as you say, if water does find a way through, and it very well may, the CB has a fighting chance. the drywall, not so much

    damn, i wish i could rewind a year and do this over. that shower would have been done a long time ago.
  12. dhagin

    dhagin builder:anti-builder

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  13. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

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    Post(s) deleted by John Whipple
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  14. dhagin

    dhagin builder:anti-builder

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    Remember folks, a photo of wet tile is not a Kerdi failure. Need more info: to begin, what does the structure consist of - wood, concrete, steel, other? is the shower floor sloped? how much? is their a mortar bed or foam shower pan? etc... these are just a few of the first questions we need to evaluate a shower failure. Any shower failure. Just trying to help you all understand a simple, professional installation where drywall has been used successfully for decades.

    Folks can choose to ignore facts, that drywall as a substrate in a Schluter shower system is a fine professional and code approved installation, all they want. I choose to live in a fact based world where long term successful results inform current and future trends. Have fun all. :)
  15. DonL

    DonL Banned

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    Yes you are correct, May I get a Bump Please ?

    Thanks in advance.


    Pissing_Contest.jpg


    Have Fun Everyone.
  16. eurob

    eurob In the trades

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    Drywall in wet area ..........as post above.

    Pissing over drywall.JPG


    and this is from a supplier

    Quote : '' Why PANEL REY Drywall?

    "Tainted drywall has flooded the North American market. How does this affect our investments, let alone our health? Tainted drywall emits reactive sulfur gas at levels strong enough to damage copper wiring and pipes, undermining the quality of your renovation and putting your heath at risk for the sake of saving a few bucks. At Drywall Depot it is our goal to provide safe, reliable products to the marketplace; products that are safe for your family and safe for your customers. So we went looking for a drywall made here in North America that was tested safe. Panel Rey Drywall was the clear choice. As part of the Consumer Product Safety Commissions (CPSC) ongoing investigation into tainted drywall the Lawrence Berkeley National Laboratories conducted independent testing to determine among the different drywall suppliers what exactly their levels of emission were. Those results can be found here and here. The Panel Rey Drywall Product results were outstanding, surpassing commonly used product lines. Panel Rey Drywall is strong, light, and safe, as well as ULC & ASTM listed. Why take chances on cheap budget drywall when Panel Rey Drywall is already an affordable choice proven safe. So when it comes to your home, your business, your customers, remember: price isn't everything.â€

    And of course CBU is just not comparable to drywall , ever.
  17. dhagin

    dhagin builder:anti-builder

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    b

    *
    u

    *
    m

    *
    p

    *
    !

    :)
  18. DonL

    DonL Banned

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    LMAO

    That is Great.
  19. Vegas_sparky

    Vegas_sparky Eat kitty

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    I hope you got it under control now, Pete. I have another bathroom to do, and 8+9 is going to be what I use(over CBU of course).

    Share pics if you have em. :)
  20. pete c

    pete c New Member

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    I hope I do too. I have one concern. That is the drywall to kerdi bond. I thought I would be smarter than the install video and put up large pieces around corners rather than do separate flat pieces with taped corners. When I was applying the kerdi, there were a few spots that pulled away as I rolled the sticky ardex on. I ended up cutting these pieces open and using ardex to glue them to the wall.

    So what I have learned from all this is that if you are a DIYer, I highly recommend ardex over CB. It is pretty much idjit proof and even if you goof up, odds are pretty good that you'll get away with it as the CB will stand up to occasional moisture.

    So, there is definite advantage to CB/ardex. Install time may favor drywall/kerdi. I don't know enough to guess if it does. Price, it seems to me is on the side of CB/ardex, assuming the shower is large enough to use the entire ardex mixture. If the shower is very small, perhaps there is a price advantge with kerdi/drywall. But, it ain't much.
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