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carole2000_gw

Installing Undermount Sink without Using Brackets???

carole2000
14 years ago

Hi,

I'd like to hear you opinion about this so-called standard practice in the Bay Area, CA.

I'd like to install a 2cm slab over a plywood. The fabricators said they will cut a hole into plywood, put my ss sink over the it, then some silicone on the rim of the sink, then put the slab over the sink. That means the sink rim will be between the plywood & the slab. When I raised a concern about replacing the sink later, they said that it's rare to replace a stainless steel sink down the road. It's partly true because my old ss undermount sink installed in between plywood & tiles survives over more than 20 years.

The fabricators said he never installed a sink with brackets in the past. However, if I insist, they can do that. I need your advice before making a hole in my plywood.

Thanks,

Carole

Comments (24)

  • azstoneconsulting
    14 years ago

    Carole2000-

    The application thet you are describing - 2CM over plywood with a SS sink
    and no brackets - for THIS application - is fine IMHO....

    We do this all the time - with Stainless Steel type sinks ONLY.

    The ONLY negative to this method - is thet "IF" you ever have to
    remove the sink for any reason (damage is usually the only one here)
    you'll be "S.O.L" (sorely out of luck).....

    Sounds like your fabricator is willing to work with you on this -
    just make sure that he's using 5/8" and NOT 3/4" plywood, and the
    plywood itself is ACX grade -and NOT a cheaper grade - like CDX (it
    tends to warp really easy and has been known to effect the flatness
    of the stone once everything is installed.)

    hth

    kevin

  • carole2000
    Original Author
    14 years ago

    Hi Kevin,
    Thank you so much. WeÂre very impressed with those pictures. Very informative!!! It looks like you use those pictures to teach us how to install the sink by ourselves. I wish this website has some kind of archive to store the useful information like that. Thanks again.

    I also think that itÂs OK with this kind of installation but my DH still wants to install the sink after seeing the Undercounter Mounter Braxton Bragg that you posted in this website.
    Could you please, spare some time to post the pictures explaining how to install kitchen sink with this? IÂd like to make sure that it will be installed correctly. Do we still cut a hole to put the faucet in? With this kind of sink setter, will the sink stay till in the future? In the pictures above, I saw that you put some adhesive to keep the sink from moving.

    If it was you, which way you prefer to install your sink & why?

    Thank you,
    Carol

  • writersblock (9b/10a)
    14 years ago

    > I wish this website has some kind of archive to store the useful information like that.

    It does. Where you see clippings on the right side at the top of a post, click "clip this post" and it will get saved to your clippings, which stay accessible even after a post has archived off.

  • azstoneconsulting
    14 years ago

    Thanks Carole for your very kind remarks... I post stuff here on GW to HELP
    consumers, and help them have more freaking tools at their disposal - so they can
    make good decisions as to their countertop projects go.... That's also where
    my NaturalStone101 webste comes in to play - it's there - NOT to sell ANYTHING
    (sounds crazy - huh?) it's there to help folks in an unbiased and
    objective way...

    anyways - are YOU installing this yourself - because if you ARE - I'd really
    caution you - slab Fabrication and Installation is not for the newbie - and I'd
    ONLY recommend stuff to you if you and your DH had the skill sets to do this
    kind if work..... There's PLENTY of Fabricators doing this for a living right now-
    and I'm sure you can find SOMEONE that could do the install for you.

    As far as "what would I do in MY home?" I will answer this way - EITHER method
    will work well - the "advantage" of using the "Undercounter Mounter" from
    Braxton Bragg ....
    is that IF you EVER have a problem with your sink - any kind of sink for that matter..
    you can remove it if you have it mounted using the Undercounter Mounter.

    for the money - I think is it sells for between $20 and $50 dollars - I think
    that it is a GREAT form of insurance for a homeowner - what happens when
    "Little Timmy" starts juggling monkey wrenches, and drops one on the stainless
    steel sink, and makes a HUGH JAZZ sized DENT in the steel? IF the sink
    has been sandwiched in between the stone and the plywood - you'd better
    get used to seeing Hugh's DENT in your sink..HA!

    BUT...... With the Undercounter Mounter - all you'll have to do is loosen the nuts
    that hold the sink in place, lowering it away from the stone until you can litterally
    remove the sink and replace it with a new one (that you'll charge Little Timmy's
    folks for)
    This is - if the cabinet space under the sink will allow you to maneuver the sink
    out of the sink base cabinet and replace it with the same style and size..

    here is a pic of the Undercounter Mounter:

    With this type of mounting option - the sink can still move around, but when you
    turn the "set screws" to raise the sink up into position - after the stone is set in place -
    the sink will "snug up" to the stone - then you back down the screws a turn -
    squirt in your silicone, and tighten the screw back up and - voila!! (SP?)
    you're done..

    I will try to do a podcast on this that shows how the Undercounter Mounter
    works - using video... watch for it soon at Naturalstone101.com

    hth

    kevin

  • dawn_t
    14 years ago

    Do you mean the Sink Setter?
    I just installed mine yesterday and it's pretty nifty (using mine under butcherblock).

    {{!gwi}}

    {{!gwi}}

  • dawn_t
    14 years ago

    Ahhh - Kevin beat me to it :)
    I am such a s-l-o-w typist!
    Dawn

  • azstoneconsulting
    14 years ago

    Ladies and Germs -

    There are a couple of variants of this system - it's kind of like:
    When you have to sneeze - you reach for a box of....?
    "Kleenex", "Tissues", "Puffs", etc - bottom line - you blow your nose in any
    of them the same way..... regardless of what they are called....

    that's all.....

  • carole2000
    Original Author
    14 years ago

    Dear Kevin,
    Don't worry. I didn't intend installing anything. I'm not good at it. In addition, my fabricator is willing to do that for me without extra charge, except for the material that is not expensive. The reason I asked is that I feel that you know the product so well while my fabricator never installs it, so I just tried to help him.

    Dawn t,
    Thanks for the helpful pictures. I guess that my fabricator is able to do that without difficulty.

    However,I just wonder that without adhesive, does the sink move? If we fasten the clamps tightly to the counter top, do we have room for caulking? I guess that we need time for the adhesive cured & the slab settled down, does he have to come back the next day to fasten the sink up & put the caulking??

    He'll come to my house tomorrow so I tried to gather the maximum information so that we can talk to him.

    Thanks again,
    Carole

  • azstoneconsulting
    14 years ago

    Carole2000-

    It sounds to me (so far) like you have a really good guy who will be doing your countertops -
    many guys are very closed minded about A. New Ideas, B. New techniques,
    and C. taking a suggestion from a customer and running with it (without a lot
    of resistance)

    Many Fabricators are very egotistical, and resent anybody trying to offer THEM
    any new ideas or advice,

    There are those though - on the other hand -
    and it sounds like you may have on of the real good ones
    that actually DO listen to new ideas from their customer,
    try new concepts and keep an open mind in trying a new approach -
    other than the old "That's the way we did it back in the 40's and 50's" like
    I'd always hear from my master journeyman - during my own apprenticeship
    in the late 70's.

    The Natural Stone industry has it's share of "instant wonders" - guys who -
    ten years ago were flipping burgers or still in grade school - they get a few
    years of Granite Fabrication under their belts, and they think they know EVERYTHING....

    Sounds to me though - like your Fabricator - AIN'T one of those ... I think he's
    going to make an effort to make you happy - and in my opnion - he's off
    to a good start by being open minded on this UMS issue...

    just my .02 cents worth - I think you have a real good guy there for your Fabricator....

    hth

    kevin

  • karenm_2010
    14 years ago

    To azstoneconsulting: I want to install a 2 cm granite counter top over a plywood substrate. In reference to the Undercounter Mounter, can this be used in this situation? I see your photos of sandwiching the sink lip in between the plywood substrate and the granite, but in case I ever do need to replace the sink, the Undercounter Mounter sounds better. But I can't picture how the Undercounter Mounter would work with substrate. It seems the plywood would show at the sink cutout. Thank you for your help.

  • sheila99
    14 years ago

    Karenm, I have the same question. Please let me know if you find out how to mount the sink using 2cm granite and plywood layment.

  • davidro1
    14 years ago

    Cut a larger hole in the plywood, instead of cutting it just large enough to match the sink.
    Large enough to allow you to use a mounting device, that one can then remove when desired.

    There is no need to have plywood under the entire surface area of the stone.
    The stone won't disintegrate.

    h.t.h.
    --

  • azstoneconsulting
    14 years ago

    I will kindly go ahead and.... disagree with Davidro1 on the point of
    support and plywood - for a 2CM application - it's better to have the entire
    cabinet covered (subtop wise) with a single layer of 5/8" plywood. This offers
    more support for the entire stone assembly, and lessens the chance of a
    weak spot fracture - where there is no plywood suptop - and the stone
    has pinpoint pressure at impact. WITH the plywood underneath - it
    will take more force to fracture the stone - that if there is no plywood
    under the same spot when the same amount of force is applied.

    I go through this as an expert witness all the time, and this is a fact for
    a Natural Stone application. Yes - many Solid Surface manufacturers only
    require strips of subtop material as Davidro1 has mentioned - but for
    a Natural Stone application - I am pretty sure that MIA specs still call out
    100% support from subtops - this means no strips.... anyways - that"s how
    I have been doing it for the last 25 years without failures or complaints...

    hth

    kevin

  • sheila99
    14 years ago

    question for azstoneconsulting, the brackett ends will have to go under the plywood right? won't that change the height of the plywood as compared to the rest of the counter top underlayment around the area? The pictures you have above show the sink being place on top of the plywood using the plywood for support. What happens if we use bracketts? Or do the brackett ends go on top of the plywood? in that case won't they push the stone up? If possible would you please post a picture, it really is worth a thousand words!

  • azstoneconsulting
    14 years ago

    Hi Sheila99-

    What do you mean by "the bracket ends" - OK... I read into your Q a little more...

    Here's the deal-eo on the corbels/brackets. The plywood subtop (and I am
    presuming that this is a 2CM overhang scenario you're talking about) extends out
    PAST the edge of the cabinet - so that the plywood will be under the
    full extension of the "overhang". The corbel or counterbalance plate sits
    UNDER the plywood and is attached to the pony wall or solid wall section with
    screws, and is glued and/or screwed to the underside of the plywood.

    This has to be done so the "plane" of the plywood is not raised or lowered -
    affecting the stone. the corbel or counterbalance plate is there for support
    to the entire assembly (plywood & stone) and supports against downward
    force and resulting travel that would cause flex in the plywood, and fracturing
    in the stone.....

    This is proper & kosher! - the corbels or counterbalance plates go UNDER the plywood,
    so you have stone, then plywood, then corbel or counterbalance plates.

    does that make sense? You are right though - pictures ARE worth a thousand
    words - especially when I blather on and on.... ;-)

    i will try to find a pic to post on this thread - but I have to go right now....

    hth

    kevin

  • davidro1
    14 years ago

    Kevin, this is what will say it better: in the ideal case, a sink would be almost as wide as the cabinet and the area to cut out (larger) would have to be 1" on both front and back sides in order to accommodate the brackets. Not that big a deal. Sorry to have made it sound worse than that. I didn't ever mention "strips". Hope this helps.

  • davidro1
    14 years ago

    Sheila99,

    Another thread about MDF made me think of bumping this one.
    The need or "application" here is to have a horizontal plane support.
    Plywood is good for this.
    Metal is good too, when made for this. Angle iron, C channel, tube, etc.

    My response above got no action, so far.

    Sheila99, think of your overhang in front of your cabinet edge. It can easily be more than an inch, and it takes a lot of weight when people lean on it.
    On the other hand, nobody ever suggests that your granite will not be strong enough to hold together at that edge. And nobody ever will.

    Around the sink hole, removing 1" from the plywood to give room to place brackets will not hurt the plywood support under your granite. With brackets your edge is supported, very well.

    If your sink is a whole lot smaller than the cabinet on which it is placed, and if the brackets only support two sides of the sink, then there is an ever-so- slightly relatively weaker support on the unbracketed side of the sink that is farthest from the cabinet side; just saying this before anyone else does; however it's not worth much attention, it's not a big deal, it's one inch less plywood, and I doubt anyone is going to tell us that this single inch will make a difference.

    hth
    -d

  • azstoneconsulting
    14 years ago

    Sorry Davridro -

    I couldn't see this thread there for a while, and I have been busy
    with other stuff here in AZ.... not diss'in ya Bro - OK??

    As far as this whole debate goes - here's the dealeo as far as I'm concerned:

    The smaller you make the stone around a sink opening (ie; 1" vs 2")
    the greater you increase the opportunity for fracture - Davidro - you are
    correct in your argument about the application, etc.

    The important thing to remember (and I think that you have pointed this out
    very well) is that the "plane" or "application" of the stone - has to be supported
    and remain flat without movement or "flex"....

    Plywood subtops do this very well, but adding steel re-enforcement
    to the recipe - IMHO - does it even better.

    I had a friend that actually laminated 3/4" x 3/4" box steel tube
    to the underside of a 2CM laminated front edge assemblies - so that
    the steel was not visible because of the front edge lower half covered it -
    he'd set the assembly directly on top of the cabinets. Sadly, he had to close
    his doors last year (it's NOT been fun here in PHX), so I do not know
    what his long term success rate will be - he started doing this process in
    2006.... so we'll see.

    The other "ingredients" that make or break this whole scenario are:
    1. stone thinkness - 2CM or 3CM
    2. type of sink - stainless, cast iron, plastic, etc
    3. size of sink
    4. size of cabinet base sink is set in
    5. depth of countertops
    6. set back of UMS opening from front edge of stone
    7. amount of support for sink and countertop from cabinet assembly
    8. type of subtop material used (if any)
    9. type of rodding used (if any)

    1. method of sink attachment and support (type of clips or support assembly used - if any)
    2. movement of the home, cabinets and/or countertop assembly (if any)
    3. amount of downward pressure or force applied to the sink assembly
      (gravity, content of sink and weight of garbage disposal and associated plumbing
      attached to the sink- all pulling down on the sink and the stone)
    4. potential for water penetration into the subtop

    Bottom line here - is that Davidro has some good comments on this thread,
    and there are multiple scenarios that will play out in determining whether
    or not an UMS application will hold up - long term

    hth

    kevin

  • shw2653_comcast_net
    12 years ago

    We had an undermount sink installed with Silestone countertops. The installer used wood strips to hold the sink in place and some sort of adesive. Two days later a milky like liquid was flowing out into the sink from between the sink and counter. We were told it was "probably" a bad tube of adhesive. They finally came back and reinstalled the sink but still used the wood strips. I don't like the idea of using the wood strips.

    What is your opinion of this method?

  • kmw1177_gmail_com
    12 years ago

    We just had granite countertops installed.5/8" plywood was used, but I can see the plywood bowing out under the 10" overhang. My installer proposes to fix the problem by cutting the plywood out from under the overhang. Is this ok to remove the support?

    Also of concern, he mounted my cast iron undermount sink WITHOUT the brackets I supplied. Is this safe? He proposes to fix the problem by now installing the brackets underneath the counter...for what purpose, I can't figure out...

  • DowB
    10 years ago

    Why would you want to use plywood to mount any sink? If the sink is ever damaged you will never be able to replace it without removal of the countertop! Cinclips simply install from below and can easily be removed.

  • Circus Peanut
    10 years ago

    Or even better than plastic Cinclips, just use 2x4s as braces and get even more strength and stability, with infinite room for fastener distribution and load balancing.

  • DowB
    9 years ago

    Circuspeanut, Cinclips are much easier to install and faster than any other system available and you really don't even have to lay on your back to install them like all others, plus you can hook up the plumbing and put the sink to use right away!

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