(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 7 of 7

Thread: Bathtub walls

  1. #1
    DIY Junior Member Johnny Drama's Avatar
    Join Date
    Jun 2008
    Location
    VA
    Posts
    15

    Default Bathtub walls

    I've removed the tiles and sheet rock from my bathroom walls and have the studs exposed. I've currently got 1/2" hardibacker ready to install and I have to fur out the studs to match the hardibacker up to the old 5/8" drywall. Questions:

    1. Where the hardibacker meets the old drywall should I use the regular drywall tape or the fiberglass mesh type tape?

    2. Will regular joint compound adhere to the hardibacker?

    3. Should I return the hardibacker and get a 5/8" mold resistant drywall to make my life easier?

    Thanks

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,405

    Default

    Use the Hardiebacker. Put a vapor barrier behind it, lapping the bottom edge over the tiling flange of the tub. The sell shims at some lumberyards that make it fairly easy...tack them up, put up the vapor barrier, then the Hardie.

    Often, the tile extends beyond the outside of the tub itself. Since that area is typically dry, you can end the cbu there, and put the outer row of tile on the drywall. Use the mesh tape.

    If the studs are not plumb, sometimes it is easier to add in sisters to get the whole wall plumb rather than shimming th eold ones out. Keep in mind that with the thinset under the tiles, you may not need as much of a shim as you think. That outer edge only needs a small amount, and the thinset over the Hardy should be plenty. If it was on a floor, that'd be a different thing, but you're not walking on the walls. You don't want that last row to bow out, though.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  3. #3
    DIY Junior Member Johnny Drama's Avatar
    Join Date
    Jun 2008
    Location
    VA
    Posts
    15

    Default

    What exactly should I use as a vapor barrier? I've looked on the web and everyone talks about a vapor barrier under flooring and in attics, but no one mentions it behind bathroom walls (oddly enough). Also, there was no vapor barrier behind the original walls, so is it really needed?

  4. #4
    Plumber jimbo's Avatar
    Join Date
    Aug 2004
    Location
    San Diego
    Posts
    9,001

    Default

    Cement board products are not damaged by moisture, but they are not water proof. Dampness seeping through a grout crack can cause mildew BEHIND the cement board.

    4 mil poly sheet is OK. I like 15 pound roof felt.

  5. #5
    DIY Junior Member Johnny Drama's Avatar
    Join Date
    Jun 2008
    Location
    VA
    Posts
    15

    Default

    Got it. So 4 mil poly sheet...that's just a think piece of plastic basically, correct?

  6. #6
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,405

    Default

    0.004" thick...not very much.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  7. #7

    Default

    Hi all,

    I agree with jadnashua 0.004" is not too much.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •