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  1. #1
    Join Date
    Dec 2005
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    Michigan
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    Default No-caulk shower?

    Saw an interesting detail. Shower with plastic base and tile walls. Appears well done. There is NO caulk between the bottom tiles and the shower base. No caulk, no grout, nada. Empty space about 3/16".

    I'm thinking it's not a bad idea. Drains any water that gets behind the tile. Thoughts?

  2. #2
    Join Date
    Apr 2008
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    Kennett Square, Pa (chester county)
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    Default Re: No-caulk shower?

    Sounds like someone meant to go back and caulk but never made it. I would think I'd be a tough spot to clean and to me would look unfinished.
    Darrel Hunter

    "You can't build a reputation on what you are going to do." - Henry Ford

  3. #3
    Join Date
    Aug 2012
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    13

    Default Re: No-caulk shower?

    Some 4 peice tubs "fiberglass" are ment to have the gap for water to travel but not tile.

  4. #4
    Join Date
    Jun 2004
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    Los Angeles, CA
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    Default Re: No-caulk shower?

    Gunk will get in there. Caulk it.

    Actually, post a picture of it with the camera down real low and shine some flash into the gap, so we can see what is exposed.

  5. #5
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    Default Re: No-caulk shower?

    KG, I have nothing to do with that installation, I just noticed it in passing and made mental note of it. I don't have a picture and won't be going back there.

    Yes typically this is caulked. This detail has bothered me for quite some time. I have seen many tubs and showers (with plastic bases)that have drywall rot at the lower corners OUTSIDE the tub. Water behind the tile travels down and can't drain at the bottom (caulked). So it travels outward to the outside lower corner and wets the adjacent drywall. It has no other way out.

    What is needed is a bottom weep, but leaving voids in the caulk is not a good solution. We need a better mousetrap.

    In a sense, grouting that joint with real porous grout might be a better solution than caulk. The grout might crack, but it lets the water out.

  6. #6
    Join Date
    Jun 2004
    Location
    Martinez, California
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    14,829

    Default Re: No-caulk shower?

    Historically the water in the mortar bed drained down and out through the grout between the last tile and the prefab pan or bathtub, the problem is that the grout in that joint eventually cracks and falls out, when painters painted homes they always took a little bag of white grout and re-grouted that joint. The worst happened when the caulking manufactures started making and selling tile caulk, people thought it was a great idea to put something flexible in there that wouldn't crack and fall out, the problem is that it seals up that joint sealing in the water leaving no way to escape, then sealant manufactures jumped into the act making tile sealers in a futile attempt to seal the tile so water never got into the mortar bed, but it never has worked, at best sealers seal the tile from staining, not for water penetration.

    Some years ago I decided it a good idea to leave the grout out entirely to give maximum drainage to the mortar bed, but had trouble convincing customers that even though it looked unattractive it would provide better drainage, I had one tile setter who left the grout out of one tile in each wall, eventually I went back to the old fashioned way of using grout telling customers that it was natural and unavoidable to have cracks in the grout, maintaining the grout was routine maintenance like painting, the worst thing you can do is put sealant in there, PICT1177.jpg Note that this is a rental property of mine, the tenant put sealant in the joint between the tile and the tub, forcing all the water in the WonderBoard horizontally to cause damage, I stupidly let a tile setter "save me money" by using WonderBoard rather than a real mortar bed, but mortar bed or backer board, the water has to drain out somewhere.

    Edit: I just saw DG's post above, it took until the early 60s for the stucco industry to mandate weep screeds at the bottom of stucco walls to allow the stucco to drain, how long is it going to take fro the tile industry to realize that mortar beds need to drain just like stucco walls? A stucco weep screed wouldn't look good in there, I looked at a Schluter trim product some years ago but decided that it wouldn't work because of no drain holes.
    Last edited by Dick Seibert; 09-01-2012 at 12:30 PM. Reason: DG's post
    “It is not an endlessly expanding list of rights —the “right” to an education; the “right” to health care; the “right” to food and housing. That is not freedom. That is dependency. Those are not rights. Those are the rations of slavery – hay and a barn for human cattle.” - Alexis de Tocqueville

  7. #7
    Join Date
    Feb 2012
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    New York
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    Default Re: No-caulk shower?

    Dick I'm glad you posted that. I recall many years back (ten?)this very subject came up and you posted the same response.

    I agree with you about grouting the bottom joint. I never did it until I had one client calling me back every 6 months for one of three bathrooms we did for her. The bottom joint that was caulked (the most heavily used shower in the home) was blowing out and getting all crappy looking in a few small areas. After two clean outs and caulking I finally decided to grout the entire bottom joint.

    Haven't heard from her in two years since it was grouted. Was back early this year for other work and it looked fine.

  8. #8
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    Default Re: No-caulk shower?

    Yes I now vaguely remember talking about this a few years ago.

    Ideally what is needed in the bottom joint is something very porous. I'm thinking 1/4" backer rod made of open cell foam. You press it in, it breathes, you can easily replace it if necessary.

    Any inventors out there? Get to work.

  9. #9
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    Feb 2012
    Location
    New York
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    656

    Default Re: No-caulk shower?

    Quote Originally Posted by dgbldr View Post
    Yes I now vaguely remember talking about this a few years ago.

    Ideally what is needed in the bottom joint is something very porous. I'm thinking 1/4" backer rod made of open cell foam. You press it in, it breathes, you can easily replace it if necessary.

    Any inventors out there? Get to work.
    and comes in matching colors, you just invented it!

  10. #10
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    Apr 2006
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    Kiawah Island, S. Carolina
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    Default Re: No-caulk shower?

    Dick, if installers would use the proper amount of adhesive to eliminate voids behind the tiles, and if they mixed, slaked, installed, packed, cleaned, and cured the grout properly, there would be virtually no water or moisture within the tile assembly. That being the case, the industry requirement for flexible joints should be followed.

    The issue of weep screeds keeps surfacing, but even with weep screeds - or voided grout joints, if the adhesive and grout are not done correctly, moisture will still invade the tile assembly.

    By the way Dick, I am an outspoken proponent of mortar setting beds, but a mortar setting bed is not required for a top-end installation. As I have said before, I have inspected hundreds of thin-bed over backer board installations that were problem free, and I have seen hundreds, if not thousands of mortar bed installations that failed miserably. I began my tile career in the SF Bay Area ripping out mortar bed showers that failed - some of them less than two years old. What you install tile with is less important than HOW you do it.

    In closing, I have participated in many court cases involving voided or cracked joints. Both conditions create unhealthy and unsightly conditions. In a restaurant environment (and in many home kitchens) both conditions quickly result in a build-up of e-coli. We all have e coli in our guts, but when concentrations are high enough, people get seriously ill.

    No invention is needed to prevent moisture intrusion. Good tile installation practices reduce moisture intrusion to practically zero.

  11. #11
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    Michigan
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    Default Re: No-caulk shower?

    Quote Originally Posted by mbyrne View Post
    Dick, if installers would use the proper amount of adhesive to eliminate voids behind the tiles, and if they mixed, slaked, installed, packed, cleaned, and cured the grout properly, there would be virtually no water or moisture within the tile assembly.
    Michael, with all due respect, I no longer believe that and I think I might be able to prove it.

    Since I started this thread, I have become involved (as a spectator for now) with a very interesting case. Corner shower on plastic base. Cement backer, liquid membrane. 12" green marble installed with appropriate thinset and epoxy grout. Bottom and corner joints sealed with silicone. Tile was sealed with Miracle 511. There are in-progress pictures of the install, a few years old.

    The shower is fine, no cracks or voids. There was wet and crumbling drywall at the lower corners outside the glass enclosure. About 4-5 square inches at each corner. Wet drywall was dug out locally and area left open. Each time someone takes a shower, after 15 minutes you can see a tiny amount of liquid water weep out of the thinset layer at the lower corners, outside the enclosure.

    It is very clear that water doesn't get behind the tile through the grout, it's epoxy and intact. It must be going through the porous marble. Sealing the marble apparently is not preventing it.

    My theory is that sealing the marble still allows some water through, but retards back-evaporation. The thinset layer remains saturated because of twice daily use and the silicone at the bottom joint doesn't allow drainage/evaporation at the bottom. Water then weeps to the outside and soaks the adjacent drywall.

    After some observation and further inspection be several people, it is proposed to remove the silicone at the bottom joint and replace with regular grout (not epoxy). The drywall will NOT be fixed, so the area can be observed for some time. I will report on the results.

  12. #12
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    Suburbia (Washington, DC area)
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    Default Re: No-caulk shower?

    I have seen a similar situation with limestone walls in a steam shower, which has convinced me of the same thing, that sealed stone does allow moisture in but reduces drying.
    We had a shower built with both a CPE plumber's pan and also Kerdi on walls, curb, bench, and (because it's a steam shower) ceiling as well.
    ABout two years later, clients want us to fix the caulk at the floor/wall intersection. It's a bit moldy and gunky.
    One of our guys starts to cut out the old caulk, and water starts running across the floor.
    And keeps running. For over an hour.
    He leaves, we come back the next day, there's still some water coming out.
    There must have been a LOT of water in that wall. Apparently the caulk was holding it in.
    We put weeps in the caulk. Grout would be another idea, but we got away from it in the first place because it cracks at corners, usually in the first heating season.

  13. #13
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    Default Re: No-caulk shower?

    Doug, what kind of weeps did you put in the caulk? Just left some voids?

  14. #14
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    Default Re: No-caulk shower?

    dgbldr,
    If you are convinced that epoxy grout will stop water or moisture, where is the water going through? I don't know all the facts about your shower, but in my experience, the first place to look for an entry point is the attachment screws for enclosures. I have built hundreds, if not thousands of showers, some were slapped up, but when I learned about grout density and no adhesive voids, the end of mold, leaks, discoloration, moisture build-up/daming/trapping.

    When I lived in California, all of the tiles I installed were porcelain from Michelle Griffoul Studios; the stone tiles I used ranged from very hard and impervious black granite to very soft "Indian" slate - never a problem with moisture. My own bathroom is made from "Indian" slate, a relatively soft and flakey stone. About once a month, I pick up a chunk that has flaked off. Nevertheless, the setting bed has remained perfectly dry for three years of use: cut off a section 18-inches off the floor to install a leg-shaving perch and discovered the setting bed was completely dry, grout joint damp only to 1/4 of the depth.

    One of the reasons I harp on about grout density and adhesive voids is a study done at the TCNA labs with porous grout: looked good on the outside, but water rushed into the joints as if there were no grout at all.

  15. #15
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    Default Re: No-caulk shower?

    Michael, I can't speak to the porosity of all stones, but I have tested several kinds of marble in the past that were porous and would saturate clear to the backside.

    I also have a peculiar granite in my own house (on a non-bathroom floor) that is porous. It's light grey. You can put a few drops of water on it and watch it soak in. The tile shows a spot until it dries.

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