"over installing" a tub?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by beachfront71, Nov 12, 2012.

  1. beachfront71

    beachfront71 New Member

    Jan 15, 2011
    newport beach, ca
    Hello to all and appreciate the feedback/advice ... great forum !

    Here is what I am looking to achieve..

    We have a Kohler Archer #1123 drop in tub I purchased for another bathroom that went unused .. I now have a guest bathroom and would like to use this tub in an Alcove setting even though it is a drop in tub. I know that is not ideal but it has been done.

    The problem is the tub setting, I tried to set the tub this weekend in Mortar and realized the floor is uneven just enough that the tub would rock with minimal pressure so I ripped it all out and am going for round 2 ..

    The tub can be set in mortar or you can use construction adhesive on the leveling blocks.

    Here is my plan for round 2 and would like any thoughts:

    1. Dry install the tub and shim to level
    2. Secure shims via adhesive
    3. Apply one larger 3" high pile of mortar to the dead center of where tub will go
    4. Apply construction adhesive on the 4 blocks
    5. set the tub, level and leave it alone

    I have read a few posts on using one method or the other (CA vs. Mortar) but have not seen any where both is used ..

    The goal on my end would be
    1. Support for under the tub and soundproofing (mortar)
    2. Tub locked down for no movement (CAdhesive)

    Any thoughts here?

    Also, since this tub does not use ledgers around the outside and I will be tiling over the lip, why would I not apply CAdhesive to where the tub and 3 walls meet in order to secure that area down as well to prevent any flexing ?

    THanks again.
  2. kreemoweet

    kreemoweet Member

    Sep 7, 2009
    Seattle. WA
    Leave the mortar out. Since the tub will be sitting on its 4 legs, it does not need mortar, and any mortar put under it will
    likely slump and shrink away from the tub, thus accomplishing nothing. Fiberglass is a better sound insulator than mortar.
    I do not understand your comments about tiling over the lip, since this tub doesn't have tiling lips, or the lack of ledgers,
    since this tub requires a deck/ledger under all four sides. Are we talking about the same tub?
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    You SHOULD use "ledgers" around the rim of the tub. In addition, you need something like the K-1179 tiling bead around the alcove's perimeter as a leak preventative. The front edge will have a "knee wall" to support it at the same height as the ledgers.
  5. beachfront71

    beachfront71 New Member

    Jan 15, 2011
    newport beach, ca
    Thanks guys,

    Regarding tiling over the lip .. This drop in tub has a small decorative lip around the outer edge that we hant to tile over so the tile ends up at the deck of the tub

    Regarding the ledgers and tiling bead .. this is the one tub that Kohler does not have a tiling bead for, I was thinking of adding some bitchathane aroudn the 3 walls area before having the moisture barrier installed.

    Also, the owners manual specifically states this tub should not use ledgers and should rest on the base only ..

    I thought the mortar might help with any flexing .. seems all the new tubs use a mortar bed now.

    Thanks again.
  6. kreemoweet

    kreemoweet Member

    Sep 7, 2009
    Seattle. WA
    The installation instructions say not to HANG the tub by the rim, which is not saying there should be no ledgers. Every plastic
    tub needs support under all four sides. Just plop yourself down rather heavily on the rim and you will see exactly why. The
    manufacturers literature DOES say, however, that this tub is not suitable for the kind of installation you contemplate.
    Maybe you will get lucky, though.
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