Undermount sink keeps separating from granite

stnjanDecember 16, 2007

We recently had granite installed in our kitchen and our stainless steel undermount sink keeps separating from the granite and falling. The first time it happened was about a week after our granite was installed. Our contractor came out, sealed it again, and said we definitely should not have any additional problems. Well, here we are two months later and the sink fell again tonight. We are going to call him in the morning, but does anyone know what the is doing wrong?

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pcjs

Did they use any type of clips or mounting blocks. I wouldn't think sealing it with some type of caulk would be strong enough to hold the weight of the sink and anything in it.

    Bookmark   December 16, 2007 at 7:13PM
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raehelen

We just had our granite installed too (yeah), and the sink was put in Saturday. He siliconed it (I'll find out tomorrow exactly which kind it was), and propped it up with wood from underneath, and clamps on top, and we let it set for 24 hours before my DH installed the faucet. By the time he got that done (tonight), it had been well over 24 hours, and we filled up the sinks with water to test for leaking, everything seems fine. DH did the research on holding power of silicone, and it is very impressive. Kitchen guy is coming by tomorrow to clamp it in place just as a back-up, but supposedly that is unnecessary.

Maybe he/you guys aren't letting it rest/set long enough before using it the first time? Hubby's asleep right now, but tomorrow I'll ask him exactly what was used.

    Bookmark   December 17, 2007 at 3:37AM
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azstoneconsulting

There's alot of contractors that rely only on a bead of
silicone to adhere the sink to the underside of a stone
counter top when it is an undermount application.

In my opinion, that is NOT a good practice and will
result in exactly what you are experiencing - the
sink seperating from the counter top and sagging or
completely falling away from the underside of the counter top.

The technique that I have ALWAYS preferred, is to not
only seal the flange of the sink to the underside of the
counter top with silicone, but ALSO use a MECHANICAL means
of support from underneath to hold the sink in place -
so the weight of the sink, garbage disposal, associated
plumbing and content of the sink - all combined - will
not act in such a way in conjunction with gravity -
as to "pull" down the sink assembly
from the underside of the counter top.

There's a number of things that can be used:

1. Undercounter Mounter (a metal support system that
is usually implemented at the time of installation)

2. Plywood subtop (used primarily with Stainless Steel
sinks)

3. Wood Cradle Frame

4. Manufacturer's Metal Clips

5. Chemical Concepts self adhering Clips

#'s 1 through 4 are best applied at the time of installation,
with #5 being able to be utilized in a "retro-fit" application -
after the sink has been installed and THEN you
find out that ONLY silicone or bondo is all that was
used to hold your sink up in place....

I would suggest that yor contractor consider using
some of the Chemical Concept clips that are available
through Braxton Bragg. This in my opinion, will solve
your problem once and for all.

hope that helps

kevin

Kevin M. Padden MIA SFA
Fabricator, Trainer & Consultant to the Natural Stone Indusrtry
www.azschoolofrock.com

Here is a link that might be useful: Braxton Bragg's Peel-N-Stick Mounting Clips for Undermount Sinks

    Bookmark   December 17, 2007 at 6:36AM
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organic_donna

Kevin,
I already purchased the BB peal-n-stick clips but have not installed them yet. Have you ever put any in? Any suggestions to using them.
Donna

    Bookmark   December 17, 2007 at 8:13AM
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azstoneconsulting

Donna-

Yes I have and they work GREAT!!!

Couple of tips:

READ ALL of the instructions completely.

DO NOT use Acetone or any other solvents to clean the stone
where the clips will be mounted

DO make sure that ALL dust particles are removed from where
you are going to stick the base part of the clip (the part
that has the threaded stud mounted to it)

DO use a Shop Vac to suck up ALL of the dust from the
stone where each clip is going to be stuck to the stone

DO "dab" the areas of stone with a clean rag wetted down
with clean water.

DO allow the areas of stone to completely DRY before
sticking the clips.

MAKE SURE that the temperature of the stone and ambient
room temp is ABOVE 60 degrees farenhite - both 24 hours prior
to and AFTER you stick the clips to the stone

MAKE SURE that you allow AT LEAST 24 hours to pass BEFORE
you put the retaining clip on the stud and tighten it up
with the securing nut. The glue will work best if it allowed
to dry AND cure for at least 24 hours BEFORE you put the
little clip thingy and the nut on and torque it down all the way.
KEEP IT NICE & WARM in your kitchen - so the glue will cure properly on the clips.....

Use at least 6 (six) clips to hold the sink in place and
you should be good to go!!!

Best Regards

kevin

Kevin M. Padden MIA SFA
Fabricator, Trainer & Consultant to the Natural Stone Industry
www/azschoolofrock.com

Here is a link that might be useful: AZ School of Rock

    Bookmark   December 17, 2007 at 9:00AM
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organic_donna

Kevin,
Thank you for the great tips. I have a stainless undermount sink and the cabinets were notched out to fit the sink, just a small amount. The installers only used silicone. My bathroom fabricator said the sink was pulling away from the granite.
There isn't enough room in front of the sink for the CC clips so he was going to cut them to make them fit. Will that work? There is room in the back though. They did run the faucet over the sink lip in the back of the sink to hold the sink in place.
Donna

    Bookmark   December 19, 2007 at 7:48AM
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dyhgarden

Our Shaws apron front sink is undermounted. It sits completely on a solid shelf with holes where needed for the plumbing. The silicone is used to keep water out, not to hold up the sink, so I'm surprised by that there is another way to mount these.

    Bookmark   December 19, 2007 at 8:56AM
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DowB

If you want the easiest, fastest, strongest ( holds over 550lbs) method of mounting undercount sink then you need to look into cinclips as they support the sink from the cabinet. There is no wait time! Use the sink as soon as it is mounted. Anyone can use and install this system, only takes minutes to install! I recommend contractors purchasing them through GranQuartz. This will definitely end all problems with sink mounting in my opinion.

Here is a link that might be useful: GranQuartz

This post was edited by DowB on Mon, Mar 24, 14 at 21:34

    Bookmark   February 9, 2014 at 12:15PM
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kevdp4

One of the most seen problems of stone countertop installations is undermount sinks separating from the stone. In almost every failure the common factor is adhesives used in the install letting go. Whether it's adhesive used to glue thew sink direct to the stone (please no), glue-on tabs glued to the stone (still relying on adhesive) or anchors glued into the stone.
A mechanical system is much more reliable (meaning no adhesives) and stronger.

    Bookmark   February 14, 2014 at 9:31AM
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raee_gw

This thread reminds me that I need to order the sink harness system from BB and get is installed.

Just about the first thing my GC crew said when they came in after the counter and sink was installed with adhesive only was that I needed to get one--they have to regularly re-install sinks that are only adhesived in.

The second thing they said was to comment what a lousy place the seam was in (in their opinion). And a lousy job.

    Bookmark   February 14, 2014 at 11:19AM
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gr8daygw

Our contractor screwed blocks of wood to the inside of the cabinet just under the sink to help hold it up. They did a lousy job so my husband redid them and reinforced them. You could also build a cradle which just means wood vertical to the floor of the inside cabinet front and back on each side with wood at the top horizontally to make a frame to support it.

    Bookmark   February 14, 2014 at 11:45AM
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DowB

My installer said all he had to do was to simply stick the cinclips to the side of the cabinet and push up to the lip of the sink and attach the cinclips to the cabinet. He gave me a guarantee that the sink would never come down again. He said it was the best system he ever worked with.

    Bookmark   March 24, 2014 at 9:31PM
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feisty68

We are DIYing our cabinets and planning to use a "Sink Setter" to support our undermount sink. Looks like it can also be used to deal with a sink that is falling too:

Here is a link that might be useful: How to repair a granite undermount sink with The SinkSetter

This post was edited by feisty68 on Tue, Mar 25, 14 at 0:26

    Bookmark   March 25, 2014 at 12:25AM
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Trebruchet

You can spend $38.00 for a sink setter or $4.99 for a Hercules Universal Sink Harness. The HUSH is a one-person installation.

    Bookmark   March 25, 2014 at 8:10PM
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andreak100

Trebruchet - I didn't see this before our granite was installed and really wish that I would have. They used wood 2x4's that are bracing the sink, which I guess will work, but it is just ugly. Things are pretty tight in our cabinet for our sink, but I'd love to get the HUSH system if we can retrofit it. I've looked at the photos online and I can't tell how high up we need to get beyond the lowest point of the sink bowls.

*Is it sufficient for the "clips" that are screwed into the side of the cabinet to be only slightly higher than the bowl?
*The sides of our cabinets are plywood - I'm assuming that will be fine to screw into and we don't need any other blocking or anything, correct?

I've attached a picture showing how things are right now in the sink cabinet. On the right is the cabinet, to the left is the one sink bowl, and underneath, you can see the 2x4 that's providing support.

    Bookmark   March 25, 2014 at 10:49PM
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feisty68

The HUSH is nifty. I didn't know about it unfortunately. I paid CAN$28 for the sink setter, and it was a one man installation job.

    Bookmark   March 25, 2014 at 10:59PM
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Trebruchet

*Is it sufficient for the "clips" that are screwed into the side of the cabinet to be only slightly higher than the bowl?
*The sides of our cabinets are plywood - I'm assuming that will be fine to screw into and we don't need any other blocking or anything, correct?"

andreak100:

I've retrofitted HUSH's before. Simply screw the clips to the top of a piece of plywood, then screw the bottom of the plywood to the cabinet sides. This pushes the clips high enough to work perfectly.

Plywood cabinet sides are plenty strong enough to support the harness and sink.

    Bookmark   March 26, 2014 at 7:58AM
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oldryder

I am a fabricator.

Only a schlock fabricator will install a sink, even a vanity sink, with only the silicone caulk to hold it in place.

There are a variety of mechanical systems and techniques to secure sinks that can be employed.

A previous poster commented that sinks separating is one of the main problems with granite. That is simply incorrect. My shop has done many thousands of sink installs and we have never, ever, had one fall away from the counter.

If a fabricator tells you the silicone adhesive is adequate I'd STRONGLY suggest you look elsewhere.

    Bookmark   March 26, 2014 at 3:19PM
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feisty68

Is "plumbing strapping" an acceptable method? That's what our fabricator says he does to support sinks. I'm assuming he means this?

    Bookmark   March 26, 2014 at 3:30PM
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Trebruchet

fiesty68:

It depends if he has a method by which he can place the strapping under tension.

    Bookmark   March 26, 2014 at 5:42PM
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feisty68

Thanks Trebuchet - I see what you mean.

    Bookmark   March 26, 2014 at 5:55PM
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DowB

Why would you want to use products and practices that are time consuming and failure rates are high? Get rid of separation anxiety by using a product that will never fail and are super easy to install or remove if necessary! I recommend cinclips from GranQuartz. That is what my fabricator used in my house and when he left sink was useable and he did not use any epoxy or glue. Just trying to help with the problem.It's your call! Read more at cinclips.com

This post was edited by DowB on Mon, Mar 31, 14 at 23:05

    Bookmark   March 27, 2014 at 11:46AM
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kevdp4

oldryder posted... "A previous poster commented that sinks separating is one of the main problems with granite. That is simply incorrect. My shop has done many thousands of sink installs and we have never, ever, had one fall away from the counter. "

oldryder I believe you must have misread my post. I didn't say "that sinks separating is one of the main problems with granite." I said, "One of the most seen problems of stone countertop installations is undermount sinks separating from the stone."

I am glad to hear you have had no problems, but I don't think you can say you are unaware of sink separation problems from other companies that use adhesives only to mount sinks. I believe we are in agreement that there is a right way and a wrong way to mount sinks. Adhesives only without a mechanical system is just wrong.

    Bookmark   March 28, 2014 at 11:02PM
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Shelly4nier

This happened to me and my 5 MONTH OLD BABY WAS IN THE SINK GETTING A BATH AT THE TIME. I had just had the granite & sink installed 2 months ago. They came out to fix it but with GLUE/APOXY again.. I feel like it still was not fixed right what are my options?
YES MY SON IS OK but he was in it full of water going head first down into a corner cabinet sink.

    Bookmark   April 25, 2014 at 5:19PM
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feisty68

How HORRIBLE Shelly.

One option is the sink setter I linked to above.

    Bookmark   April 25, 2014 at 5:33PM
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jellytoast

That sink setter looks awesome, feisty!

    Bookmark   April 25, 2014 at 5:38PM
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Trebruchet

Shelly4nier:

Until you confirm the sink has been properly mechanically fastened, your child must stay out of the sink.

Stick a camera under there and post the pics, please.

    Bookmark   April 25, 2014 at 7:44PM
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chach123

My kitchen sink dropped out and I ordered what was to be an easy and cheap fix. It was a was a sling - what a contraption that was - I threw it out. I then researched every fix out there and I have found the easiest and sure way to remount a kitchen undermount sink and never worry again. I used a product called Cinclips. All I needed was the clips, screw gun and silicone. I'm a woman and I didn't need a man to fix it! I did not need to touch the stone, just placed the clip on the inside of the cabinet as instructed and screwed it in. Very simple. I got mine at their website Cinclips.com, but then found it later at a local hardware store. It was well worth the price - I would have paid double.

    Bookmark   July 17, 2014 at 10:30AM
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Trebruchet

chach123:

The "sling" was undoubtedly the Hercules Universal Sink Harness. It can be tricky to adjust for the inexperienced.

I've used the Cinclips with excellent results and for the less mechanical among us, they can be the best choice. Very fast and simple to install, but cost 7 times as much as a HUSH.

    Bookmark   July 17, 2014 at 11:41AM
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chach123

Time is money, and I'd gladly spend 7 x the cost for something that's not frustrating like HUSH. I will be hush about HUSH; in my opinion, it's not a product that I would endorse. I'm a homeowner without the skills of a mechanical engineer and Cinclips was the ticket for me.

    Bookmark   July 17, 2014 at 12:20PM
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AlZ.Heimer

One reason for separation might be excessive stress on the sink. For example, a new disposer could have been installed and the angles of the pipes are such that the weight of the disposer and the angles of the pipes stress the sink/counter joint. When installing disposer, especially when changing from a 1/3 hp to a full hp, the weight is quite a bit more and usually larger. Because it is larger, the pipes will likely not fit without changing the angles. If installed by stressing the pipes, it will in turn, stress the sink which might be why it continues to separate. Glued pipe fixtures require replacement to get the right angles. Hope this helps.

    Bookmark   August 14, 2014 at 1:22PM
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Trebruchet

AlZ.Heimer:

There is no disposal made that will substantially alter a sink held with a Hercules Universal Sink Harness.

    Bookmark   August 14, 2014 at 8:58PM
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mmmggg

I made an account here just to say THANK YOU TO KEVIN. It made my life better.

    Bookmark   November 20, 2014 at 5:37PM
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Juno_barks

I followed Trebruchet's suggestion for my undermount apron front sink, and purchased the HUSH. It was relatively easy, though I also added some corner brackets to distribute the force on the sink. I could have done it myself, but did allow my husband to help ;) We've been using our sink for a month and everything is rock solid.

    Bookmark   November 20, 2014 at 5:48PM
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