Shower Mortor Bed

Discussion in 'Shower & bathtub Forum & Blog' started by tazz3769, Dec 15, 2009.

  1. tazz3769

    tazz3769 New Member

    Messages:
    2
    Location:
    Philadelphia PA
    I installed a motor bed over the floor pan using a mortor cement mix and mixed to the consistancy so that the mix formed a ball in my hand.

    Check it last night and some areas where cracked and started to fall apart. Is this a sign that I did not use enough water or am I usin the wrong mix?
  2. krow

    krow Plumber

    Messages:
    906
    Location:
    Ontario, Canada
    Is there such a thing as "mortor cement mix" ? (i don't know, I'm just asking.) I have used mortor mix and I have used concret mix.

    If you placed a mortor mix, it won't stand up in the shower base.
    Most tilers use a "dry pack" which is mostly sand and portland cement. 4 parts sand, 1 part portland cement. Concrete mix will do just as good if mixed on a dryer side consistency
  3. frenchie

    frenchie Jack of all trades

    "mortar". Just sayin'.



    Cracked & falling apart, usually means you mixed it too wet - but if it was holding in a ball shape, probably something else.

    What did you use to mix it? I'm thinking too much entrapped air, maybe...

    Did you work "work" it into place, and make sure to get any bubbles & voids out, or did you just drop it in, loosely, & smooth out just the very top layer?

    Did you keep it damp as it set up, or was it allowed to dry out before it had a chance to set? You don't mention when you installed it - it should be kept damp for a few days.


    It's kinda hard to guess which of these it might be, without seeing it / being there.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    If this was put over a wooden subfloor, and you didn't put something like some plastic or roofing felt on the floor, it can draw too much moisture out of the mix, decreasing its strength. Excess water causes shrinkage cracks. Mixing up deck mud should let it hold shape if you squeeze a ball in your hand, but it should not drip water.
  5. Tileman

    Tileman Tile Man

    Messages:
    3
    Location:
    New York
    Exactly what mix did you use, and over what, a slab or wooden subfloor?
  6. tazz3769

    tazz3769 New Member

    Messages:
    2
    Location:
    Philadelphia PA
    I used Mason mix commercial grade concrete and I laid it over the gray PVC pan liner. Under the liner is a preslope of concrete over backerboard over subfloor.

    The mix seemed very dry, but was able to form a ball.

    I poured the mix and packed it with a wood float.

    The PVC liner is a little tight around the curb not laying flat in the corner, but I thought the weight of the mortar would push it down.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,937
    Location:
    New England
    Doesn't sound like you used the right stuff. Deck mud is a 4-5:1 ratio of sand to portland cement, and you should not have or need cement board underneath the preslope. For good help on building a shower, check out www.johnbridge.com Tile Your World website and check out the 'Liberry' section for a tutorial on building a conventional shower. Compare that with what you have and see how close you are to industry convention. They have a good forum, too. Lot's of tile pros, lot's more than here.
  8. Tileman

    Tileman Tile Man

    Messages:
    3
    Location:
    New York
    As stated, you used the wrong mix, that has lime in it, good for the curb construction, but not for a floor.

    4 parts mason to 1 part portland is ideal for mud jobs and shower pan floors.
  9. tilelayher

    tilelayher New Member

    Messages:
    35
    Any luck with this project? I am 20 minutes from Philly if you want it done right. Yo Richie!
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