Finishing up a Kerdi shower questions

Discussion in 'Shower & bathtub Forum & Blog' started by MikeQ, Apr 6, 2014.

  1. MikeQ

    MikeQ New Member

    Messages:
    87
    Location:
    Washington
    Sorry, double post!
    Last edited: May 16, 2014
  2. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

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    4,167
    Location:
    North Vancouver, BC
    Mike - sealing the tile is tricky. Using a tiny wire brush (brass) is often the only way to remove this grout from the tile. It needs to be done while grouting and at the tooling and clean up stage.


    Yet another reason why a tile mock up board is so important.

    When sealing floor tile it's so important not to get the sealer on the tile's edges. This creates a bond breaker and can I have seen help efflorescence weep up through the setting material along the sealed tile edges.

    So much can wrong with tile, grout and sealing. Your bathroom shower looks awesome - you should be very proud of your hard work.

    Don't sweat the blank stares - often the men answering the question there rely on manufactures recommendations. The real pro's there rarely help out on the general discussions. Lame wanna be posters seem to control the info mostly. Just look at the post counts of some of these ya-who's.
  3. MikeQ

    MikeQ New Member

    Messages:
    87
    Location:
    Washington
    I had asked about this issue on the John Bridge Tile Forum but, as usual, was greeted with blank stares. I do not believe a normal tile/grout sealer would have prevented the grout from embedding in the stone pits (some of the voids are like miniature jagged "caves" with openings smaller than the insides).


    Fortunately, I am the homeowner and I'm a reasonable person. But I know what you mean!

    In the end I decided to prioritize getting a consistently good bond in the grout joints over aesthetic issues of residual grout residue. If perfect aesthetics was a higher priority, I would use masking tape over the entire floor and tediously cut out every grout joint with a utility knife. Alternatively, I could have used a mosaic product without surface pits. But I'm happy with the result.
  4. MikeQ

    MikeQ New Member

    Messages:
    87
    Location:
    Washington
    I did share ballpark numbers there, around $6K material cost plus a lot of hours.

    The tile cost was very high because I could only approximate the colors I envisioned by ordering tiles glazed to order, full boxes only. So I have a lot of the 3x3 colored tiles remaining.

    Time spent was excessive due to inexperience and the desire to fully research every detail before proceeding. Contributing to the time/labor was the very precise planning required due to very tight clearances and the fact that the floor and walls did not start out square and level. The extensive curbing detailing (top and bottom) added more than expected to the imaginary time sheet. Also, I thought the tempered glass wall would reduce labor (vs. framing/tiling) but I think it was no easier. A simple, minimalistic, ultra modern shower would have been much quicker.
  5. MikeQ

    MikeQ New Member

    Messages:
    87
    Location:
    Washington
    For future reference, the bi-fold added considerable cost/installation time compared to a swinging door. Typically, they are installed to open inwards in order to eliminate door drippage on the floor, post-shower. I obviously didn't have room to do that but my floor has a membrane extending up the baseboards so I wasn't too concerned with that.

    Certainly. I'm confident the performance of the Bostik Dimension urethane grout on the shower floor will outperform traditional cement based grout. It's rated water absorption is <1% and it has Microbial protection built in. Also, the joints are less than 1/8" wide but are a full 5/8" deep and fully packed. Because I didn't pre-seal the mosaics or use anything but a slightly damp sponge during clean-up, there should be a good bond.

    What is your concern with the Ditraset thinset?
  6. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,167
    Location:
    North Vancouver, BC
    Effloresence

    I stopped using non-modified setting materials for my shower floors years ago. Do many turn white. I chaulk it up to low end thin-set.

    A few of the premium setting materials do not contribute to efflorescence at all. Printed right on the bag.

    Sadly one supplier does not allow this with their products. So - change suppliers is my motto.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,019
    Location:
    New England
    This TCNA document describes what efflorescence is, what causes it, and how to deal with it if it occurs. Note, that in a properly installed surface membrane over a proper slope (no birdbaths or flat areas), and the fact that there's very little mortar there, and most all grouts are modified and typically sealed...in a well built shower, this is usually a non issue - it can become much more of an issue over a typical liner and thick mudbed. Also, the purity of the cement and how well the sands and fillers that are used were washed can make a big difference. One reason why white thinset is more expensive, is that the materials must be purer, which helps in the whole situation (iron and magnesium are the primary things that make the cement grey - removing them gives you what is called white mortar and also removes some of the salts). https://www.tcnatile.com/faqs/32-white-residue-on-grout.html

    There must be enough water going through the cement based products to dissolve the salts that produce efflorescence, and in a surface membrane, with proper slope, modified grout, and sealer...it becomes mostly a non-issue. But, keep in mind, the TCNA studies have shown 75% of the tiled showers are not done correctly, so the fact that it rarely happens to any degree in a properly done one is somewhat masked - the majority in this is not a good example.
  8. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,167
    Location:
    North Vancouver, BC
    Jim - have you ever spoken with Schluter's Head Tech. You most know him. The man's name is Dale Kempster.

    Next time your at work ask him what he told me about Effloresence. In regards to what he and the TCNA or what ever group he referenced spends most of their time looking into. What type of common problem does Dale have to deal with.

    I'll give you a clue.

    The first and last letter of the word has an "E".

    When you have spoken directly too him. Then get back to us. Tell every one that John has some legitimate concerns and then go back to selling Kerdi and Ditra for your office.
  9. MikeQ

    MikeQ New Member

    Messages:
    87
    Location:
    Washington
    Looks like I really screwed up royally. I had no idea this was so common!

    Sad. All that hard work down the drain. :(
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,019
    Location:
    New England
    If it happens to you, or even if it doesn't, report back in a year or so. This is much more common over a full mudbed and a conventional clamping ring drain and liner. Most grout used is modified, and that limits any salt migration. A surface membrane with a properly installed thinset, doesn't have much salt to dissolve (the reason it is called thinset method). A premium mortar with well-washed sands and fillers, has limited salts.

    Don't lose sleep over this.
  11. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,167
    Location:
    North Vancouver, BC
    You mentioned earlier you had nice clean tile edges. Your grout might save you...

    But if the grout turns white. And your translucent grout looks creamy white. And you have a powdery substance on the surface of the tile edges then it might just be effloresces.

    Over the years I have asked why this was happening on my Kerdi showers. I was told things like "You might have over watered the grout" "You might have use expired grout" "Your sponge was to wet" - I've been told a lot of crap over the years.

    I wish I had been told "Use a better setting material" "Use a better grout" - but at the time manufacture's printed instructions (which by the way have to be on site at all times) conflicted with this.

    Kerdi - Ditra : Never Again
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