Silicone to close gap between countertop and undermount sink

8 years ago

Hi,

The installers applied some kind of clear silicone to the rim of our undermount sink and then pressed it upwards. It left some gaps and they're not coming back for another week or two.

1. What kind of clear silicone can I use to fill the gaps?

2. How long does it last before I have to scrape it off and re-apply?

3. Is there a clear silicone with antibacterial features? The sink will be exposed to a lot of germs?

Thanks a lot!

Featured Answer

PRO

Joseph Corlett, LLC

8 years ago

last modified: 8 years ago

"1. What kind of clear silicone can I use to fill the gaps?"

Any 100% clear silicone will work, but this should be done by the installers, not you. You don't want to give them the opportunity to say you screwed it up.

"2. How long does it last before I have to scrape it off and re-apply?"

The silicone that's doing the gasketing job it's meant to do should have been applied to the sink flange liberally enough that when the sink was clamped tightly to the bottom of the top, it squeezed out. The squeeze-out should be tooled. Any additional silicone as you are applying is topical and cosmetic in nature. Peek under your sink. If you see no silicone squeezing from the flange, have them remount your sink properly.

Your top looks like estone, but in natural stone tops that have been rodded, improperly gasketed sinks can cause catastrophic rod failures which I charge $800=$1,600.00 to fix and you can usually still see the crack.

"3. Is there a clear silicone with antibacterial features? The sink will be exposed to a lot of germs?"

Keep it clean and it will be fine.

Sort by:Oldest

Comments (9)

Ann
Original Author
8 years ago
Hi Joseph - thanks for the referral to order from Dani but I'll need it for this Tuesday, so I don't think it will get here in time.

I did see the counter top installer squeeze the silicone onto the flange of the sink and press it upwards. It did ooze into the openings, but, there were some gaps. He returned today (counter top was too short and they had to cut another piece), and scraped off the fine line that oozed out. I almost fainted when I saw him use a zecto knife on the rim of my brand new sink!!! I asked him to please use painter's tape so I would get a nice even line. I've seen some disastrous caulking jobs! It looks fine now.

My countertop is Caesarstone Quartz. My concern is that he did not use brackets to hold the sink up. I saw him mix 2 types of gluey concoction together and applied it underneath the sink somewhere. He showed me how it formed into a very hard substance after a short time. He said he's been installing countertops for 6 years and never had a problem.
Related Discussions
Acrylic undermount sink with laminate countertop?
Q
Comments (11)
Nolamom, sorry for the late reply. I hadn't checked this thread for a while. We used a Corian Counter-Seal ring. The KD says something seemed to have changed in the adhesive Corian tells the fabricators to use, as during a 2 year period about 5 failures like ours happened (2007-late 2008). The fabricators swore they were using the approved stuff and were certified, so it wasn't their fault. The Counter-Seal people said it was past the 1 year warranty, so it wasn't their problem. The KD quit selling the undermount rings as he couldn't afford to cover more new counters for replacements. I just saw some ads for a new overmount sink that has a very flat thin lip, so it seems to almost look and work like an undermount sink. Here's the info--it's from an article on CNET. "How about an easy-(and inexpensive) to-install overmount sink that gives you the look of a flushmount? That's what you get with MicroEdge, the latest offering from Blanco. It's an ultrafine rim--1.25 mm--that installs over virtually any counter material for a precision, near seamless edge. The sink isn't cheap--you'll spend around $600--but the install is standard enough that you can do it yourself or hire someone to do it for you for far less than a flush or undermount." I'm was actually glad I didn't see these sinks before we ordered the granite, as I might have given in to my DH's desire to just replace the sink section of the laminate and do an overmount sink this time. If granite/quartz isn't an option, these new sinks might be workable for OP. Good luck!
...See More
question about silicone seal between counter and undermount sink
Q
Comments (10)
Thanks, all, for these messages. I think the grout is epoxy, as stoneonecorp guessed, because he mixed multiple small batches and worked very quickly, and I didn't see anything sand/cement-y involved. And I'm glad to hear that non-experts can redo that caulk sink seal with no apparent trauma. I was surprised when he told me that *I* should caulk over his grout seal. This is a guy who was recommended *very* highly by a lot of people: I called every single person on his references list and asked a lot of very critical questions. No one, not a single person, said, "he expected us to finish up the job; he told us to caulk our own counters." ISn't that part of the installation? Anyway, I think I know the answer to that. And given that he whined when we asked him to come back and re-seal the sink (which he messed up the second time as well as the first time -- all the while complaining that no other homeowner had ever asked him to do this, and that the sink is not his responsibility), I don't want him back in my house, because I think he's a jerk. So: sounds like I should recaulk the sink seal and caulk over the grout he laid. Yes? I'm going to use clear silicone and masking tape, so it looks nice. Any other tips, advice, cautions? Pamkcs, did you just rip the old sealant out with a screwdriver and clean what was behind it? As before, thanks in advance!
...See More
Undermount sink w/wood countertops?
Q
Comments (39)
We are getting ready to refinish our wood counter tops. They are over 10 years old and received no maintenance during that time. Except for heavy wear areas (i.e., the outer edge in front of the sink), all the damage is from water: dish drainers to the sides of the sink, the path between the sink and the dishwasher, around the faucet (which has a very small leak), and where the counter meets the sink. The latter two have mildew rot. Notice that the sink is smaller than the cutout in the counter, leaving a lip for water to accumulate (the hole was cut using a template included with the sink - they probably use larger holes today). I would agree with riverspots and andersons: had we given it regular maintenance (recaulk, recoat, and replace faucet gaskets every 2-3 years) it is possible that it wouldn't need to be refinished now. Note that, to maintain the appearance, you have to recoat BEFORE the finish cracks. If afterwards, you'll have to settle with the visible defect or refinish the entire counter. The butcher block counter was original finished with an indoor polyurethane. This time we will use a marine coating. And we'll find a dish drainer that doesn't get any water at all on the counter. Also, if your installing wood, try to avoid faucets that mount directly on the wood.
...See More
Best type of “sealant” 2 use b/t undermount sink & quartzite counters?
Q
Comments (7)
bridget: It depends. See if you can see some silicone squeeze-out between your sink flange and stone bottom. If you do, you've got a good seal and can just remove all the topical silicone. If not or if you're not sure, you'll probably have to drop the sink, re-silicone, and reinstall. If there isn't any silicone, I'd test for silicone bleed before caulking.
...See More
PRO
Joseph Corlett, LLC
8 years ago
" My concern is that he did not use brackets to hold the sink up. I saw him mix 2 types of gluey concoction together and applied it underneath the sink somewhere. He showed me how it formed into a very hard substance after a short time. He said he's been installing countertops for 6 years and never had a problem."

Ceasarstone recommends that all sinks are supported independently of the top which makes adhering them to tops with polyester a non-recommended procedure. See page 22.

Your sink is coming down, I promise. I just bought another 10 Hercules Universal Sink Harnesses because I used up the 10 I bought last year reinstalling sinks adhered with polyester. I can send you copies of my receipts, but one of us is lying.
Ann
Original Author
8 years ago
I was assured it wouldn't, but I'll ask the technical manager again, thanks.
PRO
Joseph Corlett, LLC
8 years ago
last modified: 8 years ago
Ann:

I hate to belabor the point, but either he or I am wrong. It's like being pregnant, you either are or you aren't. You have to choose between technical manager assurances or receipts for 33 sink harnesses over five years, not including the 10 I just ordered.
Iowacommute
8 years ago
https://www.braxton-bragg.com/index.cfm/fuseaction/store7catalog.level/bc/0,8580,9096/

The Hercules kit our great countertop pro mentioned above is $5 in that link. Maybe that is only part of the kit because that is ridiculously cheap insurance.
PRO
Joseph Corlett, LLC
8 years ago
Iowacommute:

The kit is only $5.00, but if your sink has failed and I have to come out, it's considerably more. Installing the 30 kits above (I gave a few away) represents nearly $10,000.00 worth of billed work to me.
practigal
8 years ago
For sure if you fill it in you will "mess" it up. He mixed adhesives, you'll use only one and that change in chemistry at the interface will cause the fatal problem, at least that is what I would say when it fails. You won't be able to sue him to get it right it will cost too much money, it will be cheaper to fix it. Let him fix the caulk. Get the undersink harness (or the clips if they make you happier) it's not expensive and not a huge deal to install, cheaper to fix it now, rather than let it fail first.
Ann
Original Author
8 years ago
I asked the installers to reapply the clear silicone to the joints around the sink and countertop.

I also asked them to come back asap and install the brackets, pointing out that if the sink falls, they will have to replace the countertop, possibly the sink, the plumbing, the new bottom cabinets, etc.

I appreciate the advice! I don't know why installers take such short cuts :(

Silicone to close gap between countertop and undermount sink

Joseph Corlett, LLC

Comments (9)

Ann
Original Author

Related Discussions

Joseph Corlett, LLC

Ann
Original Author

Joseph Corlett, LLC

Iowacommute

Joseph Corlett, LLC

practigal

Ann
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Silicone to close gap between countertop and undermount sink

Joseph Corlett, LLC

Comments (9)

AnnOriginal Author

Related Discussions

Joseph Corlett, LLC

AnnOriginal Author

Joseph Corlett, LLC

Iowacommute

Joseph Corlett, LLC

practigal

AnnOriginal Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Ann
Original Author

Ann
Original Author

Ann
Original Author