Wet Room - Mounting Toilet Flange?

Discussion in 'Shower & Bathtub Forum & Blog' started by baumgrenze, May 23, 2010.

  1. baumgrenze

    baumgrenze Member

    Nov 29, 2007
    We are in the process of having a ~6' x 6' accessible, curbless wet room shower/powder room installed. The installation is on a concrete slab floor, at grade. The wet room area was poured 2" below the rest of the slab, sealed, sloped, and sealed again. Half-inch radiant heating tubing has been installed. The remaining steps will be to cover the radiant heating tubes with sloped mortar and to install the slate flooring. The only provision that has been made for mounting a toilet is a black PVC drain pipe which has been sealed to the sealant below the radiant heating. I'm looking for wisdom on what I should expect my general contractor to do to provide for a securely mounted toilet flange. I trust that I am correct in concluding that the flange does need to be securely bolted down somehow. Does it make sense for him to bore holes through the sealed floor to epoxy in some bolts and then to seal the holes with Sikaflex? Would this be done after the flooring is installed? It seems a shame to damage a membrane that has passed a flood test, but then, there is only concrete slab beneath it all anyway.

    I've also encountered forum comments elsewhere that indicate that there may be code requirements for a 2" containment sill (just like for a standard shower stall.) Somehow this would negate the accessibility advantages. Perhaps the writer was working with 'old information.?'

    Thanks for any insights,

  2. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    With a concrete slab floor, the flange seldom needs to be anchored to the floor. Here, if there is no curb, there has to be a "grated trench floor drain" at the entry to intercept any water that tries to exit the shower area.
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    You made it hard on yourself. Multiple sealed layers is a problem, as if there is any problem anywhere, that middle layer won't be able to dry out. I'm an advocate of a surface applied membrane. That could have been fairly easily sealed to any penetrations. What I've seen is that there is a hump or ridge installed that is beyond the normal spray area that contains the water and directs it to the drain. ANything inside of that needs the wall area to be waterproofed via the membrane or liner. You would get some advice from people that make this type of shower at www.johnbridge.com. It depends on how far away the dry room is whether you actually need a curb or not. The hump or ridge doesn't need to be all that high, and is something you could roll over without major difficulty.
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