Does Undermount bath sink need more support?

Discussion in 'Remodel Forum & Blog' started by Gardengal, Feb 26, 2013.

  1. Gardengal

    Gardengal New Member

    Messages:
    7
    Location:
    Los Angeles
    We had our marble bath counter installed yesterday and the guys used liquid nails to attach the marble to the plywood. They put these wood braces underneath for the sink for support. I looked under the counter last night to discover one of the braces is BARELY holding the lip. There are three other braces that look okay. My question is, will this be enough for that one side or do we have to add another support. My husband called the guy this morning and he became fussy saying the sink isn't going anywhere and the only reason for the wood blocks was to hold the epoxy into place. Is this really true or is he being a putz? Thanks in advance for the comments.
    barely_hanging.jpg IMG_2277.jpg
  2. CanOfWorms

    CanOfWorms Member

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    Location:
    New Jersey
  3. Gardengal

    Gardengal New Member

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    7
    Location:
    Los Angeles
    The top is on. This is the final product. There were undermount brackets with this sink, unfortunately the guys who did this took the box and used it as trash and the mounts were in the box.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    What may be a related problem to the install...liquid nails can stain marble...not always, but it can take awhile before it's noticeable, if it's going to occur. The undermount sinks I've installed, the stone fabricator milled T-slots in the stone, and supplied t-bolts to clamp the sink in place. Not sure if I'd feel comfortable with what you have, but can't see it fully. There needs to be a full seal between the top flange of the sink and the marble, and if held in place while that cures, may be enough.
  5. hj

    hj Moderator & Master Plumber Staff Member

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    IF that white "bead" is the epoxy then it is not holding the sink or anything else. If that is what it is, the it and the "support" bracket are where the sink was supposed to be, not where it is now.
    Last edited: Feb 26, 2013
  6. Gardengal

    Gardengal New Member

    Messages:
    7
    Location:
    Los Angeles
    The white"bead" is actually the marble top. The plywood hole is bigger than the sink. Let's just say I heard the guy cuss in spanish when he put the sink in his plywood cut-out. This picture was taken under the sink with the camera pointed up. You can see the bottom left wood block is the one that's really not even supporting it. This guy isn't coming back to fix it. What should I do? IMG_2280.jpg
  7. CanOfWorms

    CanOfWorms Member

    Messages:
    174
    Location:
    New Jersey
    You can probably buy some undermount sink brackets from home despot and attach them to the plywood surround then adjust them until they are snug with the sink. Bring your camera phone in and show them a picture.
    The only problem is that plywood might get soft and not hold the screws once it gets wet or after a few years of moisture absorbtion from humidity.
    You might consider a water sealant on those open edges of plywood. It is pretty thin stuff and if you laid a towel down you could use a sprayer bottle to apply it ( like an empty glass cleaner bottle, just wash it and dry it good first). It won't prevent everything, but it will at least do a little to preserve the wood.
    It looks like a pretty poor job as it is. Do something before someone leans on it and the adhesive separates.
  8. CanOfWorms

    CanOfWorms Member

    Messages:
    174
    Location:
    New Jersey
    Looking at it again. I doubt those little blocks are even touching the sink. Once you get a few of the undermount brackets in and adjusted you should remove those blocks and put more brackets in.
    The other option (the right way) is to redo the job and replace that plywood making the proper cut.
  9. Gardengal

    Gardengal New Member

    Messages:
    7
    Location:
    Los Angeles
    Here's the same image a little lighter so really see what's going on.
    Canoworms, the blocks are screwed in from the top. The two blocks on the right are definitely touching the lip, the block on the upper right is a bit, and the one in question is holding on by a thread (if that.)
    This is so frustrating and soooo unavoidable. IMG_2280.jpg
    Last edited: Feb 27, 2013
  10. Dr.Guacamol

    Dr.Guacamol New Member

    Messages:
    9
    Location:
    California, USA
    alternative support

    Perhaps an option is first
    to first spray or brush a sealer up along the block edges,
    then build support for that one corner - from underneath. This would take someone who could purchase and handle the materials of say, 8' of double wall 3/4 " tubing placed along the sink in that gap, and then another piece of plywood block screwed up onto the existing as well as the tubing.
    That should help support that corner.

    Funky. But much better than ripping things out.
  11. Gardengal

    Gardengal New Member

    Messages:
    7
    Location:
    Los Angeles
    Hi DR. What's "8' of double wall 3/4 tubing"?
  12. CanOfWorms

    CanOfWorms Member

    Messages:
    174
    Location:
    New Jersey
    On that note you could support what is there by screwing some pressure treated 1x1 on the right and left side of the sink against those wooden cutouts. Make sure the wood is dry and straight. Then buy heavy duty shelf brackets that are 12" long and attach those to the wall and the 1"x1" pressure treated.
    Really you need to support the sink so it doesnt fall down. There are several ways to do it.

    Good luck.
  13. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

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    Liquid Nails? Seriously??? What a joke.

    The braces for the sink are Mickey Mousse as well.

    We typically use some Strong tie strapping to support the sinks. And certainly not a water based product like liquid nails to install Marble!

    JW
  14. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

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    [​IMG]

    Our last under mount sink.

    Like a tank....

    JW
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,485
    Location:
    Cave Creek, Arizona
    That block has to be removed and a new one screwed in from the bottom so it presses against the sink rim. Normally, all of those blocks would have been screwed in from the bottom once the sink was in position.
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,485
    Location:
    Cave Creek, Arizona
    quote; Our last under mount sink.

    I really hope those chains were not the only thing holding the sink in place.
  17. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,937
    Location:
    North Vancouver, BC
    HJ we used a bead of clear silicone as well. The strapping holds the sink tight while the silicone sets up.

    These approach gives us slight adjustment of the sink and a two fold anchoring system (mechanical and chemical).

    Kitchen sinks the same way. Never used another system in the last 10 years. never gone back for a failure.

    I have fixed many other sinks that used clips and blocks before. This is so basic and so strong. Easy as pie.

    JW
  18. Dr.Guacamol

    Dr.Guacamol New Member

    Messages:
    9
    Location:
    California, USA
    oops

    CanOWorms idea seems to make sense (I'm assuming you meant about "L" brackets to support the sink.)
    But often the areas to mount to have thin "wood" material to mount to. - like the cabinet back often being 3/8" thick at best.

    It's great that JW's method has worked over time. But metal does stretch. But I guess not here?

    Before, when I was trying to write a possible solution, I erroneously wrote 8' of tubing when I meant 8". I also wrote "double wall" when I was just trying to describe some thick tubing that could bend, but once bent, would resist compression on the widest diameter from the bend (because of the bend). But really any material that would mold into that area but then would not compress or crack the sink would do. [I was trying to say like ones you see with a layer of synthetic fibers seemingly sandwiched between two layers of black rubber . - commonly for water systems that use pumps.]

    Tell us what you've ended up doing. .. or having contractor re-do.
  19. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,937
    Location:
    North Vancouver, BC
    The silicone is the holding power in this sink installation method. Silicone is incredibly strong and does a great job by itself. The mechanical strap tie is there as back up and not installed so tight that it applies any pressure on the marble.

    JW
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