Didn't know if you wanted responses only from those who could answer both questions, but I will answer anyway. I have undermount (Blanco Precis large), and the inside measurement is 19.75", but I don't think it's too large. I wouldn't go any smaller than that for the way I use it on my 8.5' x 30" island. However, since you are looking at a topmount, it adds 3" to what it takes up on your counter, so it might be more than you want to give. I really don't think the sink itself will be or seem too large in proportion to your island. The only factor is how you think you will use the counter space and whether it will be enough space for you.

Is that at all helpful?

Yes! And thank you for your response. I appreciate the input.
Cj

Can you explain why you want your prep sink to be a top mount? That seems to defeat the purpose a bit of a prep sink. If you go for an undermount style, which I think is more practical, the Blancoperforma Silgranite #515-539 (aka "new number" is 440079) has exterior dimensions of 15-1/2" x 17".

Here is a link that might be useful: Blancoperforma Silgranit 440079

Akchicago, my countertop will be Formica 180FX laminate, so I'm going to need a topmount sink.

Could you please explain how having a topmount sink defeats the purpose of having a prep sink? I'm a bit confused by that statement, and I don't want to be missing something important! :-) Thanks.

Cj

Cj47, in answer to your question, if you will be using the counter around the prep sink to prep vegetables and other food, you will want to sweep the peelings, crumbs, etc. into the sink. With a top mount sink, the rim around the sink will make it hard to sweep debris easily into the sink. If instead you are just installing a prep sink as another sink to wash hands, or get a glass of water, then it won't really matter. I had assumed you'd be using the prep sink to prep food.

As an aside, many people on this forum have a garbage disposal in their prep sink as well as their main sink. That way, the peelings, etc. from prepping can go right in the disposal. Disposals are a relatively inexpensive addition in the context of the kitchen reno. If you are composting, then of course, you won't need a disposal.

I want to add to my previous message that of course you can just sweep peelings, crumbs, etc. to the edge of the counter, and onto a sponge or your hand, and then dump in the sink. It's no big deal. It would just be easier with an undermount sink, that's all. I had a top mount sink in my last kitchen, and it was a slightly extra chore to clean around the rim, but certainly not terribly extra. I just wanted to explain why I made my earlier comment about an undermounted prep sink.

I see what you mean, now. I plan to use this sink to do food preparation--wash chicken, peel veggies, wash fruit, etc. etc. Still, since I'm doing laminate I really do need a topmount sink. I know there are ways to undermount, but then my choices of sinks are rather limited and the silgranit is not one of them.

I'm wondering if I could get another brand of granite composite sink and if it would still look OK if the Blanco is in another part of the kitchen? I never anticipated that the bar sinks would be soooo tiny--12 inches doesn't seem large enough to do the job well.

Thanks for your input.

Cj

Cj, I had the exact same problem last summer. The Silgranit prep sinks come in the oddest sizes!!

I have a formica perimeter countertop and chose to do the Silgranit anthracite super single for my clean-up sink (which I LOVE, BTW.) In my island, which is approximately 3'x6', I have a butcher block top. Since the butcher block was mostly DIY, doing an undermount would've been a huge pain. I knew I didn't want stainless steel, and the silgranit sizes weren't what I was looking for. So I decided to go with a top-mounted copper sink, which I absolutely love!

My copper sink, at 16"x14", is slightly smaller than what you want, but it works great for me. I've never had an undermount sink, so sweeping the crumbs into my hand or into the pull-out garbage in the island doesn't bother me. I bought my sink through The Copper Depot, which I found on ebay. Their price was good, customer service was great, and their shipping packaging would've withstood a tornado.

I have a Delta faucet in ORB for my copper sink. My silgranit sink has the same Delta faucet in brushed chrome. I thought the two faucet finishes would bug me, but I really don't notice it at all.

Here is an older picture of my kitchen to give you an idea of what I'm talking about.

Anyway, I just wanted to chime in with another option for you. The copper is very easy to maintain and looks great, IMO. Good luck with your decision!

I don't know why you'd sweep garbage or compost into the sink unless you had a disposal, which I can't because of our septic and local codes, and try to save the compostables anyway. (I do like having the trash pullout in the island, so I can sweep things off the island into that.) I have a self-rimming sink and don't find this to be a problem. I do all our prep in that sink and it serves its purpose in a great way. It still is a great place to scrub veggies, prep chicken, fill pots, drain noodles in a big colander, etc.

Back to the main topic, though...I agree with Alicia that you don't necessarily have to match both sinks, and you could consider another material, like stainless or copper, for the island. Or better yet, try to fit that 22" Silgranite single. :-)

Alicia, your kitchen is gorgeous! What a pretty countertop you have.

I sort of like the way the black sink disappears into the island, so I'll either keep looking for one that's the size I was hoping for or just heave a sigh and give up the real estate for the big 'un.

Going shopping tomorrow!

Cj

Cj, thank you for the nice words. :) I don't think it would be a bad thing to go for the bigger silgranit sink if you can spare the space. Bigger is usually better when it comes to sinks, IMO!

The black island sink is our copper sink. You can get copper in a very dark patina, ours looks almost black from a distance. But I guess some of your decision on sink material may depend on what kind of prep faucet finish you want.

Have fun shopping!