Undermount Sink Has Sunk Away from Tiled Counter

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by CircoTribe, Jul 2, 2010.

  1. CircoTribe

    CircoTribe New Member

    Messages:
    2
    Location:
    San Jacinto, CA
    The sink is set under a tiled counter top. The caulk is long gone from around the sink. Of course, without the caulk, the wood underneath got wet and I have a sink that is sunk. I know this is going to be a lot of work to fix.

    How do I put the undermount sink back in the original position so I can seal it again? Can we rebuild the frame? Build a new one? Would an undermount sink work on top of the counter? What are my options?

    Thank you for any help and ideas that you have!
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    You can look underneath to see how that sink is supported. Although access is tight, you can probably figure out how to get some kind of strut/bracket set up, across each end, to prop that back up. The size of the opening may not be right to just replace it with a drop in. Take some measurements.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,636
    Location:
    Cave Creek, Arizona
    An undermount sink would NOT fit on top of the countertop, but a topmount sink COULD have been used as an undercounter mount, in which case it could be relocated if you can get it out of the cabinet.
  4. mnzpasquale

    mnzpasquale New Member

    Messages:
    8
    Location:
    New York
    I actually do a couple of undermounts a month as I have a contract with solid surface company. Here is my best advice... remove all waste plumbing below, detach undermount brackets, drop sink down into cabinet.
    Sorry but now you hav some hard work ahead, try and remove all tile until you exposed plywood back to side panels of sink cabinet, once that wood is wet and the brackets give it is useless. Cut ply back to each side and replace with new piece (solid then cut-out in place dont patch with pieces, wish u could add some masonry board over ply but if its not there now that boat has sailed...you can however seal the ply top-bottom-edges with marine grade sealer(will help against moisture) then re-tile and re-mount sink. If it is a heavy cast sink you will need to upgrade to heavy duty undermount brackets and always caulk rim before you lift it in place. The main reason for this to happen is from dishwasher steam that wets underside of countertop, so do a good job sealing underside of ply, also keep that grout in good shape. Hope this helps...GOOD LUCK
  5. shacko

    shacko Master Plumber-Gas Fitter

    Messages:
    561
    Location:
    Rosedale, Md
    mnzpasquale:
    >>> The main reason for this to happen is from dishwasher steam that wets underside of countertop, so do a good job sealing<<<

    Can't get my head around that, how's the (Steam) from the dishwasher getting in to the underside of the sink? :confused:
  6. CircoTribe

    CircoTribe New Member

    Messages:
    2
    Location:
    San Jacinto, CA
    Thank you for your replies! I am taking them. I like to gather ideas and opinions before tackling a job. I'm hoping I don't really have to chip into that tile! I was figuring that whatever I needed to do, could be done from underneath. I'm not always orthodox in the my approach to problems. So I welcome even the wild ideas. They could lead to a real and do-able solution. I figure I will be ready to get at this job in a couple of weeks.

    Keep the ideas coming!

    Thank you all for taking the time to help me think this through!
  7. kitchenbathsinks.com

    kitchenbathsinks.com New Member

    Messages:
    5
    Location:
    Atlanta, GA
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,636
    Location:
    Cave Creek, Arizona
    Is the sink REALLY mounted under the tile or is there a "bull nose" trim around the inside of the opening? If so, that is on top of the sink and can be removed then replaced. Tiled in sinks are typically set on top of the plywood subsurface and then the cement is built up to its thickness then the tile installed.
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,006
    Location:
    New England
    If the wood got wet, and the plywood delaminated, or there's any particle board in the sandwich, the only way to fix this is to tear out a bunch and rebuild. If the wood is still intact and solid, you'll have to see how it was originally installed, and try to do a better job! Why it is separating is the biggest, most important question to answer. You may want to use something like RedGard to waterproof things prior to reinstalling the sink...it will do a better job than normal paint-on sealers.
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