Last row of tile above shower base

Discussion in 'Shower & bathtub Forum & Blog' started by MarkHash, Oct 3, 2007.

  1. MarkHash

    MarkHash New Member

    Messages:
    60
    Location:
    Wisconsin
    I have a single threshold rectangular shower base with the tile-lip on three sides. I have done this once before and have had great results except for the silicon caulking instead of the tile grout I used per advise from base manufacturer. It of course turned grey than black and has been an eyesore for years despite the rigorous cleaning it receives once a week. Would a grout with an extreme flexible admixture be a solution rather than caulking where the two dissimilar materials meet, or is there a more mold resistance substance I could use? I have been considering just leaving it bare and just letting it breath also since there will be cement backer board flush with the tile lip anyway.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,950
    Location:
    New England
    Go over to www.schluter.com and look at their Dilex line. This is a tile-in expansion joint that will allow you to eliminate the grout in that area, and there is a different one that can be used in the corners so you'll have no grout in the shower at all, at least for those junctions.

    Prior to installing the cbu, you should run a vapor barrier down the walls and overlap it onto the tiling flange of the pan. there are several alternatives, too. RedGard by www.custombuildingproducts.com is a paint on surface waterproofing material or Kerdi by www.schluter.com is a waterproofing membrane (sort of like wallpaper, but waterproof) that would keep moisture out of the backing. Putting waterproofing immediately under the tile has great advantages since there is so much less to dry out inbetween showers.
  3. MarkHash

    MarkHash New Member

    Messages:
    60
    Location:
    Wisconsin
    Wow....great answer. Similar to a flashing problem I am dealing with on the outside right now......great solution, and it looks like the big orange retailer near me is a dealer. Thanks!
  4. 100% silicone, not siliconized latex caulking, is the right stuff to use, in case you are willing to try that first before retiling.

    GE 2000 is one of these 100% silicone products.


    david
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,950
    Location:
    New England
    HD can order the stuff, but you may have to tell them they can! They do stock some profiles, but I don't think they stock the Dilex line. You may have better luck at a local tile store or on-line. One place that has good service is www.tileexperts.com (if the link doesn't work, google them) at a lower price. Shipping can be messy unless you can use shorter pieces, since those trims come in 2.5M lengths (about 8'), and you pay a premium for pieces that long while shipping, not because they weigh much, but the shape. If you can use shorter lengths, they can cut them prior to packaging for shipment and save you some money that way.

    There is an ongoing discussion in the industry about how to best finish the joint at the bottom of the wall. Understanding that grout nor tile is ever 100% waterproof, some moisture will get behind it (not much, but if it can't escape, it can accumulate). How to allow it to escape is the problem. 100% silicon is essentially waterproof and can act like a dam for any that might try to accumulate behind the surface. This is one reason why I like the surface membranes, in the process of waterproofing the backing (cbu, or other material), it limits water penetration to the thinset immediately behind the tile and maybe the tile and grout itself, rather than the entire thickness of the cbu. thus, any moisture that does get in, can't go far, and is more likely to evaporate and not accumulate.
  6. Road King

    Road King New Member

    Messages:
    1
    how to correct without tearing out

    We have the same problem with black mold in the joint where the tiled side wals meet the tiled floor. :mad: I'm fairly sure the guy used 100% silicone on that joint. What can we do to eliminate this? Using a barrier behind the tile is obviously no longer an option for us.
    We're going to replace another shower and I want to go back with tile, but my bride says no dice until we figure how to get rid of the existing problem we have. Help! :confused:
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,950
    Location:
    New England
    The shower may not be constructed per codes. It is wrong, but not uncommon to put the waterproof layer flat on the floor, then build up the pan for tile. By code, the waterproof layer must be installed on a slope (and the tile ISN'T the waterproof layer). If yours is constructed that way, over the years, the pan will retain moisture, and it is really hard to get rid of. Mold needs moisture and food. killing the mold then sealing the grout might help, but grout sealant isn't waterproof, either.

    IMHO, a new shower built with a surface membrane, such as Kerdi from www.schluter.com puts a waterproof layer right under the tile all over, including the pan. Therefore, there's little underneath that can absorb moisture (i.e., no deckmud on the floor or cbu in the walls), so it dries out much quicker and is easier to maintain. If you tile with a good porcelain tile (which has typically much less than a 1% absorbtion rate), it's pretty bulletproof. Then, if you use an epoxy grout and the corner details (expansion joints) from schluter, there'd be NO caulk in the shower to get funky, either.

    Try wiping the shower down after use, and running the vent fan during and after the shower to help dry things out. No moisture, no mold. A mix of water and bleach will help kill it. Then, you must keep extraneous soap scum and crud off, so a good cleaning doesn't hurt periodically. That kills the two things easiest to manage - food and moisture.
Similar Threads: Last tile
Forum Title Date
Shower & bathtub Forum & Blog Plastic shower base with tile walls? Oct 10, 2009
Shower & bathtub Forum & Blog Plastic Oddities Bolt-on Tiled Shower Drain Aug 2, 2007
Shower & bathtub Forum & Blog Shower/tile backer board on old plaster - NEED ADVICE May 25, 2007
Shower & bathtub Forum & Blog Delta R10000 installation...leave plastic screen in during soldering?? Aug 14, 2013
Shower & bathtub Forum & Blog help with identifying plastic stem May 23, 2013

Share This Page