+ Reply to Thread
Results 1 to 10 of 10
  1. #1
    Join Date
    Jun 2013
    Posts
    12

    Default Is caulking necessary?

    Hi all, today I removed some caulking from between the tile and tub on a tub/shower. It suddenly donned on me that when the water gets through the grout/cement board and goes back to the tub, how does it get back in if you have that interface caulked? Then I did some googling and found this.....

    "It doesnít need to be caulked at all. Caulking at the bottom of the tub is not a required step, itís more aesthetic than anything else. Although it does contain more water in front of the surface of the tile, you donít NEED it."

    Even if I left little area's uncaulked (weep holes) wouldn't the water get in behind the caulk and eventually get moldy?

    Thanks,

    Mike

  2. #2
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    5,438

    Default Re: Is caulking necessary?

    Mike, caulk it. I would.

  3. #3
    Join Date
    Aug 2007
    Posts
    6,617

    Default Re: Is caulking necessary?

    True, grout lines can fail and allow moisture behind the tile, however it is a falacy that it will find it's way to the bottom edge and seep out on its own. What it will do is loosen the grip of the mastic holding the tile to the wall, as well as mold/mildew behind the tile. If you leave the tub/tile joint uncaulked, it too will allow moisture behind the tile and cause mold/mildew and eventual tile failure. Caulking is more than aesthetic, use it and make sure that the joint stays secure. If you notice the caulking starting to crack or fail, remove it and recaulk.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  4. #4
    Join Date
    Sep 2012
    Location
    Boston
    Posts
    888

    Default Re: Is caulking necessary?

    spruce is 100% correct. who ever wrote what you read is wrong.

  5. #5
    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    1,004

    Default Re: Is caulking necessary?

    AArgh! You never put tub-surround or shower tile up with mastic! Thinset mortar only. Mastic-based failures are far more prevalent than successes.

    I think there is some truth to the idea that in the old days with 1 1/4" thick mud job tub surrounds, the caulk of marginal quality back then, it was a "wash".
    Remember grout lets moisture in AND back out again, it's a revolving door, so caulk at the bottom is not trapping vast amounts of water because it can evaporate via alternate routes.
    Casey
    Remove not the ancient landmark, which your fathers have set.

  6. #6
    Join Date
    Jun 2013
    Posts
    12

    Default Re: Is caulking necessary?

    Thanks everyone,

    Just trying to understand the water/moisture migratory path. I'm told that the water hits the tile, seeps through the grout to the cement board, seeps through the cement board and hits whatever barrier where it runs down to inside the lip of the tub or pan. If this is correct, then my confusion was how can the water make it to the drain if you caulk the exit (between tile and tub/pan)?

    Is this how the mold was caused under my caulk?

    Mike

  7. #7
    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    1,004

    Default Re: Is caulking necessary?

    There is never enough water in liquid, running form to move downward by gravity. Water migrates through the grout in small quantities, and moves from wet to dry, so if the bathroom is kept as the dry side, it will evaporate back out into the room through the grout. The purpose of the tarpaper is to ensure that the insulation doesn't get soaked.
    Your concern for this is a real consideration, only it doesn't occur in vertical tiling, it is fully addressed in shower pan construction, where the weep holes at the level of the substrate allow for liquid water to get to the drain, not the structural members. Shower floors see the amount of standing water and larger area of grout lines to make it an real factor.
    Casey
    Remove not the ancient landmark, which your fathers have set.

  8. #8
    Join Date
    Aug 2007
    Posts
    6,617

    Default Re: Is caulking necessary?

    Quote Originally Posted by tanner3155 View Post
    Is this how the mold was caused under my caulk?
    The only time I've seen mold behind caulk is when caulk or grout has failed and moisture got behind it. The only cure is to remove the caulk, clean the area really well with a bleach solution, and recaulk.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  9. #9
    Join Date
    Jun 2013
    Posts
    12

    Default Re: Is caulking necessary?

    Excellent! thanks for the knowledge everyone!!!!!
    Now I get it.

  10. #10
    Join Date
    Aug 2007
    Posts
    6,617

    Default Re: Is caulking necessary?

    Glad to have helped. Let us know how it goes.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

Posting Permissions

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