Moisture barrier issue

Discussion in 'Shower & bathtub Forum & Blog' started by tanner3155, Jun 15, 2013.

  1. tanner3155

    tanner3155 New Member

    Messages:
    4
    Location:
    Ca
    Hi all,

    Newb here, hope someone can help. Ok, here's situation.... I live in a townhouse. I have started the process to begin tiling a small shower. I removed an old acrylic modular type shower. I was left with broken up drywall, which I removed from all 3 walls. As it turns out, theres something called a "party wall" which has to exist between two units of a townhouse. The neighbor has to have this party wall, and so do I. It has to be 5/8" type X fire grade drywall.
    Here's where my dilemma comes in. I have installed an acrylic shower pan which I intend to tile around. Since the back wall has to be the type X drywall, how can I waterproof this ????? BTW, this particular drywall is also mold resistant (purple). It's called Gold Bond XP.

    Can I Red guard the drywall, then screw the CBU to it and also Red Guard the CBU?

    Right now the only thing installed is this purple party wall and the shower pan.
    Thanks for any help

    Mike
  2. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,782
    Location:
    North Vancouver, BC
    Moisture barrier issue - with a party wall

    So that is an excellent question! A party wall is very common in multilevel or multi unit housing. You need to first repair the FireWall with the 5/8" FireBoard. You need to tape the seams and ensure there is no voids anywhere so that air can not move from your unit to theirs.

    Then you install for example some Concrete board over top.

    If you are replacing the fiber glass shower unit it would go in after the firewall is repaired.

    Do you have neighbors that live below you? If so you will also have fire blocking issues around the drain.

    If you can post a few pictures of the set up there might be another issues that needs looking at.

    DO NOT SCREW THIS UP - these codes are designed to save people's lives.

    If you can not post pictures send them to me and I will do it for you.
  3. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,782
    Location:
    North Vancouver, BC
    Was the framing in the shower build over the firewall? Often this is the case in these types of builds. It can complicate the repair.

    JW
  4. tanner3155

    tanner3155 New Member

    Messages:
    4
    Location:
    Ca
    No, there was just drywall on the framing. Funny thing is it was just regular drywall that was smashed in from when they probably installed the modular shower. It didn't even go all the way up to the ceiling. This is an old building. I would be surprised if any of the units are done the way they would be if newly built. I have a contractor coming out to have a look. I was just looking for some advice about once the firewall is fully finished, how would you make sure you have a good moisture barrier. What about the interface between the firewall (drywall) and cbu? What's the best way to make sure it does down the drain instead of back to the studs.
  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,236
    Location:
    Land of Cheese
    There should always be a firewall between residences in a multi-family unit or between a residence and attached garage.

    Whatever tile backerboard you choose goes over the firewall, the seams taped and mudded with whatever the mfg specifies, and then the backerboard must be waterproofed before tiling. The vapor is a concern it you are placing the shower on an outside wall. Properly waterproofing the shower is was is required always.
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,802
    Location:
    New England
    You could apply a waterproof membrane over that wall. Kerdi is one, Noble makes one, and there are others. Personally, I like the membranes better than a paint-on which requires several coats and a consistent coverage (not too thick, not too thin) with no pinholes to work right. Schluter has approvals to do it right over the drywall, but you could add a layer of cbu which is also an approved surface material for Kerdi. A second layer of something has the advantage that you might get it off and not destroy the party wall, but I wouldn't count on it with the fasteners - I think you'd rip it up, regardless. Thicker also means less noise transmission.
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