It appears your countertop cutout is too large. The top should overhang the sink flange with a positive reveal at the end of the curve at the top of the sink; your's appears to be nearly flush with the end of the flange. The caulk between the stone bottom and sink flange does the work of a gasket; you have none. Topical caulk such as what you're attempting is useless and doomed to failure.

How is your sink supported please?

This is fabricator error. If you can't get a larger sink, it's a top do-over. It should look like this:

Blow the pics up as large as you please, but you'll find virtually no exposed topical silicone.

Use Translucent White silicone from Axiom available from www.danidesigns.com please. Always bring the stone to the sink, never the sink to the stone.

I don't think we can do a top do-over as there is a backsplash tiled already and ripping everything out and getting a new top would be over our budget. A larger sink will not fit as the dishwasher is straight on the right side of the sink.

I will speak to the installer and see why he did this.

Doesn't bathroom/kitchen caulking withstand water?

No topical caulk can withstand the water and the movement. You need caulk between the flange and stone bottom, you don't have it, and you can't get it. Your topical caulk will always self-destruct.

I guess I got majorly screwed by the installer then...

He just got back to me on email saying

"Get a razor blade, remove the loose caulking and apply more."

Now I feel absolutely terrible...

""Get a razor blade, remove the loose caulking and apply more.""

Weekly or semi weekly at best then...................

Have you paid him yet? Never the less, if he is a reputable contractor, he will fix it right. Might be time, to have a face to face conversation with him, not an email conversation.

Yes, I have paid him, unfortunately. This problem took a couple of months to occur.

I showed him the installation instructions below when he was here (straight from IKEA) and he said that it couldn't be installed like that, which I thought was weird at the time also. But I trusted him, I'm not a countertop installer.

Now he says that I NEVER showed him the installation picture and NEVER expressed that I wanted my sink installed over the countertop so he has chosen the path to lie to get away from any responsibility. He is willing to come back and recaulk it, that's it.

He NEVER told me that the installation he would do would cause problems like this in the future.

Do I have a case against bad workmanship when he chooses to do this?

It would be a different scenario if I pushed this install on him and he told me that he could do it but it would not be his responsibility if it doesn't work in the future. But that was not the case.

This idiot has undermounted a drop-in sink.

I think @Joseph has it. The install instructions are for a drop in sink. Did you know you had bought a drop in sink?

Quick question...any reason that sink could NOT have been undermounted (in a proper sized hole of course)?

Fori:

Look at the picture please. The bottom of the apron aligns with the adjacent drawer bottom. You can undermount this sink, but you'd have to shorten the lower doors and the bottoms would not align. It looks like struglglebrother's tops are 2cm (3/4") thick, so it wasn't as disastrous as if it would have been if the tops were 3cm (1 1/4").

"Do I have a case against bad workmanship when he chooses to do this?"

Clearly. You paid for expertise that you didn't get.

The installer’s argument makes no sense. He has cut the opening larger than the sink, so it can not be under-mounted or dropped in. It is more like an old fashion tile-set sink install, except the top of these IKEA sinks are rounded and irregular so a tile-set is not possible.

This is his response to me

"If you would have shown me this picture and told me this is how I want my sink installed I would have installed it that way. It would have actually been easier for me. You made it clear to me that you did not want a top mount installation because you did not like the way it looked and it would have left a large gap between the doors under the sink and the sink itself. That being said I offered you this option and you agreed. The caulking shouldn't be lifting like that, for whatever reason it didn't bond properly. If you cant install the caulking i will come back out and reapply when I have a chance."

In the box, we opened together with the installer with the apron sink the installation instructions were and I showed him those and also the photo from the IKEA website how I wanted it. He is bending the truth with an after-construction that I never showed it to him.

If there were any problems we should have halted the installation to fix that instead of going through with something like this that causes problems.

It is a drop-in sink yes.

I spoke with another installer here locally, who is going to come here in 2-3 weeks to have a look. He also shook his head. He said maybe we can build up with wood under to stabilize the sink and lift it up, it might be the motion that is causing the caulking mostly to crack but he needs to see it with his own eyes first to see if it's even doable.

How in the world do installers do such poor workmanship? This appears to be a shallow base farmers undermount sink. He seems to have mounted this somewhere between a top mount and and undermount. I believe the undermount would have been the correct method. I just installed a retro fit stainless steel apron sink and new quartz counter tops. In regards to the counter top, the quartz counter top slightly lips the perimeter of the apron sink on all three sides, why? it looks cleaner, it is easy to clean because you have seam to clean, water cannot settle between the sink and quartz. there are no worries about visible caulking. The counter top needs to be re-cut and the sink mounted correctly, period!

“This appears to be a shallow base farmers undermount sink.”

No, it appears to be what it is - a top mount sink. Please see the instruction image posted above.

"If you would have shown me this picture and told me this is how I want my sink installed I would have installed it that way. It would have actually been easier for me."

You don't do what customers and/or designers want robotically. As the expert, it is your job to save people from themselves. If they don't go along, you refund their deposit, but never, ever, have your name on a job for which you cannot be proud.

"You made it clear to me that you did not want a top mount installation because you did not like the way it looked and it would have left a large gap between the doors under the sink and the sink itself."

This is false. This sink is clearly designed to be top mounted. It would not have left a too-large gap between the bottom of the apron and the top of the doors. I can't believe the doors didn't have to be lowered.

"That being said I offered you this option and you agreed."

You don't do what the customer wants when you know they're wrong.

"The caulking shouldn't be lifting like that, for whatever reason it didn't bond properly. If you cant install the caulking i will come back out and reapply when I have a chance."

There should be no topical caulk. There would not be on a properly installed undermount sink. There is no "bonding issue".

At the very least he is telling you the wrong caulking to use. You need a tub and tile caulking. That will be formulated to bond to the sink material.

"At the very least he is telling you the wrong caulking to use. You need a tub and tile caulking. That will be formulated to bond to the sink material."

There is no caulk "formulated to bond to the sink material". While silicone caulk has some adhesive properties, its function here is one of a gasket between the bottom of the stone and the top of the sink flange. Because of the too-large cutout here, these isn't enough area to create a gasketed bond between the two.

You cannot topically get out of this. Impossible. There is no topical adhesive solution. Even Integra's Component Bonder doesn't have enough purchase and it yellows.