We got a great deal on a sink, but then found out it is an undermount model. Our current one is a drop-in. We would not be able to add the support needed for an under mount. Has anyone installed an under mount sink as a drop in? It is a Kohler (K-5805-2) cast iron, and it's obvious we will have to do something with the larger pre-drilled holes (2 3/8"). Hope you have some advice for us.

  • 1
    Can you post a photo?
    – Bryce
    Commented Dec 12, 2013 at 20:41
  • booklet lists several #s, but believe it to be K-5805-2... What are we going to do with these bigger pre drilled faucet holes? 2 3/8. i was hoping to use this until we do a remodel on the kitchen in a cpl of yrs. May have to store it!
    – Mark
    Commented Dec 13, 2013 at 0:12
  • According to the spec sheet the holes are 1 3/8". Do the holes look like they were recut? the porcelain should go into the holes, not stopping clean at the edge
    – Jack
    Commented Dec 13, 2013 at 2:41

3 Answers 3


According to your model number it is a Kohler self rimming, surely made for drop in, not undermountenter image description hereenter image description here

  • What to do with the bigger holes? You may be able to find a faucet that suits you that will have a big enough bottom to cover your issue.
    – Jack
    Commented Dec 13, 2013 at 12:29
  • Or you can get a washer either already with the proper finish, or get one made that will match the finish of the faucet you decide on. It may not be in all cases but Moen seems to have smaller bottoms than Delta, 2 5/16" vs. nearly 2 5/8" on the few that was checked out.
    – Jack
    Commented Dec 13, 2013 at 12:44

I have installed an undermount stainless steel sink. Kohler. As a drop in. It actually looks great. I like the look of the narrow flange versus a wide bulcky rim of a drop in and the faucets installed in the counter top itself. The address were not sharp at all and was embedded and sealed with a good quality clear silicone. This allowed me to get an absolute watertight seal and it is extremely easy to clean. After install the lip is barely a 16th of an inch it's almost flush with the countertop. It looks great. I would recommend taking your time with measurements. When cutting the counter. Mine was formica I'm sorry. There is no room for error and needs to be is tight as possible allowing the narrow rim as much support underneath as possible.


Undermounts are missing a mounting rail and brackets to hold it from shifting.

If you've got 1" or more of counter under the lip of the sink, you can embed it in waterproof adhesive-caulk. It won't be fun to remove, but epoxied undermounts aren't fun to remove either.

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