can you post a sketch? it sounds like you want to install the sink - sans flange - am I reading your proposal correctly, or am I just too tired from another action packed day in my Granite Shop???? I dunno......

yawn.......... anyways.......

post a sketch showing the assembly you're proposing - so we can see what you're thinking...... instead of guessing what you're trying to do........

g'nite

Thanks for even clicking on the post late night! Okay, I quickly SketchedUp the idea. Hope the image helps convey the idea:

Will the seal be a problem in the long run? I'm surprised this is not widely done (or widely posted).

It doesn't look too bad, does it? Now, only if I could somehow maneuver that half bowl to the left side, the world would be perfect!

Yes, this is one way of mounting an undermount sink---it's how we did ours so that we'd be able to take the sink out if needed. It's not a drop-in, though---a drop-in is by definition supported by having the flanges over the edge of the counter, though some styles are virtually flush with the counter so that might work for you too. This type of undermount install is supported by braces attached to the cabinet box, so you still install the sink from below, but you can unscrew it and take it out if needed. Ours is a Kohler cast iron sink and it came with the hardware to mount it this way, but I imagine you could buy it separately too. It was pretty easy to do---you just install the brace hardware (pre-counter top) and then set the sink down on it so it's slightly below the counter level. Once the counter is installed, there are knobs you screw in to raise the sink to meet the counter, and then you caulk the edge just as with a regular install. To remove it, you'd unscrew everything and lower the sink into the cabinet.

I don't think the seal would be an issue any more than with other undermount installs---ours has been fine.

Thank artemis78! But now, I'm confused. "To remove it, you'd unscrew everything and lower the sink into the cabinet." If it's so easy, why do I hear that people crack their counter top while removing an undermount sink?

I think that's just because most people don't use the braces to install. :) (Why, I'm not sure---we decided to do it after my in-laws had a horrible experience getting their old undermount out, and I was surprised to see that our sink actually came with the hardware to do it that way---and yet people mostly don't!) It didn't seem especially difficult (we did it ourselves and just followed the Kohler instructions) so there may be other reasons people don't go that route. I think it's more common for undermount sinks to be epoxied in and rest on the sublayer of the counter, which makes it very difficult to get them out without damaging the counter.

I should also add that we don't have all that much going on under our sink (no disposal, wall-mount faucet, etc.) so possibly people either want to maximize the space in the sink cabinet (not that the braces take much space) or just feel that it won't matter because getting the sink out with all the plumbing and such below would be difficult anyway? (We'd need to take out our P-trap to make room to lower our sink, but that's pretty simple to do---could be more complicated if you had a disposal and additional plumbing connected to it.)

Kohler does sell the hardware we used separately as the Kohler undermount sink kit---it's designed for their sinks, but it has a pretty simple setup so I imagine it would work fine for many other sinks too.

use a "Sink Setter" from Braxton Bragg and you'll be fine - supporting the sink from underneath with a "cradle" type of support assembly is key in this scenario..... dont rely on "hanging the sink from the stone with silicone or polyester - especially if it's 2CM.......

hth

kevin

mudworm you can also lower a sink instead of raising it through the opening. Braces need to be unscrewed. A minor thing. In your method, the " advantage " is that the braces don't need to be unscrewed. A minor thing. But a few physical disadvantages prevent your method from being good: dimensions are one, and finetuned cutting is another one.

Why do you want to do this? It's not like sink installation technology is so esoteric or complicated. I can't remember anyone I know having to repair their sink or counter after they were installed. Even commercially, where I have much more experience, I've never seen this done.

In your sketch you are providing a ledge for water to gather along the joint with the counter. That's generally not a good idea.

Our granite guys put a bunch of clips around our undermount sinks. Screws were epoxied to the granite; the sink was siliconed to the granite; the clips were then attached to the screws to hold the sink in from below.

For removal: the clips can be unscrewed, the silicone can be easily cut; and the sink can be dropped into the cabinet. In fact we did this when we had to change out the sink due to a problem. No risk of granite damage.

I think that some folks epoxy the sink directly to the granite, which makes removal, well, challenging...

~Steve

That looks like a real p.i.t.a. cleaning problem along the inner ledge. That would not be ideal IMHO.

Hahaha... I should have known that if were a good idea, I would not be the first person to come up with it. I thought for this sink, the setup will eliminate the need for holes in granite. Water will be less likely to pool behind the sink to the backsplash. I see it as an undermount with extremely wide positive reveal. But apparently, most people don't like the look of it.

But, at least, now I know that technically it can be done. There seem to be even multiple ways to do it. I'll keep in mind whichever sink I end up with (may actually get Blanco Performa Medium), I'll undermount it in a way that removal will not cause damage. Yeah, I know, the need for removal is extremely rare, but it's better to plan ahead and not box myself (or the sink) in.

Thanks everyone for the input!

I think the only drawback to this installation would be that the flange edges on a drop-in sink are curved to allow water to flow outwards onto the counter. In your scenario, this would mean that water pools right into the caulked gap and stays; not optimal perhaps?

I think you'd have the same advantages if you raised the sink up 3/4 of an inch to be flush with the granite. That would eliminate the ledge but you could still do a clean sweep into the sink. My previous sink was tiled in at counter level and worked great.