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Support under fiber glass tubs

BOILERMAN | Posted in Construction Techniques on March 21, 2006 04:38am

I just delivered a fiber glass tub to one of our customers. I asked him if he was going to ” mud ” the base of the unit. He really didn’t know…. My question to all who read this —-do you still mud the base or let it stand under its own strength?       Larry

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  1. BETRICKEY | Mar 21, 2006 04:48am | #1

    I still mud the bottom of all of the tubs and shower bases that I install.  It may be old fashoned but I feel that it gives the base a more rigid feel.   I also don't have to worry about movement between my base and the tiled shower walls.

  2. plumbbill | Mar 21, 2006 05:10am | #2

    Depends on the tub

    I usually mud the base, but I have seen many jetted tubs that have a osb base that would rot if you mud it in.

    "There are about 550000000 firearms in worldwide circulation. That's one firearm for every twelve people on the planet. The only question is...........How do we arm the other eleven?" Yuri Orlov

  3. User avater
    trout | Mar 21, 2006 05:11am | #3

    In college I can remember a fun party--dancing in someone's bath tub with three girls--it always makes me smile.  It also reminds me of how important it is to support a tub with grout to prevent cracks.

  4. User avater
    hammer1 | Mar 21, 2006 05:17am | #4

    All the tub/shower units I have used have good supports under them. If I install a whirlpool tub, the manufacturer often recommends mudding it in. Just in case you have a party or something. I'll bet 90% of the fiberglass combo units are not mudded. With some there is also a wall cleat that serves as an additional support. Some plumbers tip out or move the units to work on the drain. If you mud in, they may not be able to move it. I always insulate around the underneath. Helps keep the bath water hot a little longer and quiets the unit down. For the well made combo units, no mud.

    Beat it to fit / Paint it to match

  5. DanH | Mar 21, 2006 06:11am | #5

    RTFM.

    If ignorance is bliss why aren't more people

    happy?

  6. User avater
    Ted W. | Mar 21, 2006 06:14am | #6

    I always mud unless there's specific reason not to. At the very least it makes for a good, solid surface to stand in. Stuffing the sides with insulation ain't a bad idea either, keeps bath water warm longer and doesn't sound like a hollow core door when you knock on it.

    -----------------------------------------------------------

    FT Job Wanted: Chicago, north side/North Shore burbs.
    http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=70809.1



    Edited 3/20/2006 11:22 pm by Ted W.

  7. davidmeiland | Mar 21, 2006 08:09am | #7

    Struct-o-Lite plaster makes an excellent base for fiberglass and acryclic tubs and pans.

    1. User avater
      Ted W. | Mar 21, 2006 08:52am | #8

      Structolite? I never thought of that. Doesn't it have to be mixed with sand or some sort of aggregate? I can see how it would easily mash into shape with the bottom of the fixture. In fact, next time I set a fiberglass tub or shower I'm gonna remember that. -----------------------------------------------------------

      FT Job Wanted: Chicago, north side/North Shore burbs. http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=70809.1

      1. davidmeiland | Mar 21, 2006 04:21pm | #16

        Just add water, makes its own sauce. After mixing you get about 15 minutes to get it glopped out onto the subfloor and the unit in place.

  8. philarenewal | Mar 21, 2006 10:26am | #9

    Another vote for mud underneath.  Makes for good "heel" even if the tub is structurally strong enough to forego.  Have heard that it tends to make water cool faster during baths.  I don't take baths, so not my problem.  ;-)

     

    "A job well done is its own reward.  Now would you prefer to make the final payment by cash, check or Master Card?"

    1. User avater
      IMERC | Mar 21, 2006 11:16am | #10

      I don't take baths, so not my problem.  ;-)

       

      we could tell that from here...Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->

      WOW!!! What a Ride!<!----><!---->

      Forget the primal scream, just ROAR!!!

      1. philarenewal | Mar 21, 2006 11:42am | #11

        Maybe I'm not using enough of my favorite cologne?

        View Image 

        "A job well done is its own reward.  Now would you prefer to make the final payment by cash, check or Master Card?"

  9. FNbenthayer | Mar 21, 2006 12:02pm | #12

    We always place sand bags under tubs (steel & CI).

     

     

     

     

    The awful thing is that beauty is mysterious as well as terrible. God and the devil are fighting there, and the battlefield is the heart of man.
    - Fyodor Dostoyevski

  10. DanT | Mar 21, 2006 12:23pm | #13

    We mud anything but cast iron tubs.  Shower bases too.  DanT

    1. edwardh1 | Mar 21, 2006 04:02pm | #14

      I have seen people use the foam in a can

    2. DonK | Mar 21, 2006 04:02pm | #15

      Warning - To those of you who talk about insulation inder the tubs, be careful. Just did one and there was a warning on the can of foam insulation not to use it under those circumstances. Possible you can crack the tub? FWIW.

      Don K.

      EJG Homes      Renovations - New Construction - Rentals

       

  11. merlvern | Mar 21, 2006 09:36pm | #17

    my shower/tub is fiberglass and the previous owner who installed it did not mud under it. i assure you it makes all kinds of pops and cracks when your showering.

    is it possible that it will crack?
    anything i can do to fill under it now?

    1. User avater
      razzman | Mar 21, 2006 09:59pm | #18

      Got one to put in and I'll be using the Structolite mixed and placed in a large plastic trash bag that will be set underneath the tub base.

       

      be formed with no stickum

       

        

       

      'Nemo me impune lacesset'No one will provoke me with impunity

    2. DanT | Mar 21, 2006 11:15pm | #19

      On a few occasions we have used expanding foam under an already installed tub with good success.  You have to be carefull not to over do it though.  Generally we try to do just spots of it around the tub either by drilling up underneath the tub or using a long tub to get back underneath from the plumbing end.  DanT

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