[c-hans]

Here’s the scenario. Powder bathroom (1/2 bath) downstairs. Vanity cabinet with a slab of marble on it. Probably cut and installed about 30 years. Really nice and good condition marble. Trying to preserve it. Existing sink is porcelain and under mounted. As best as I can tell the sink is epoxied/glued to marble vanity top. Not seeing any hardware to hold it in place. I have tied to dislodge it without success (tried chisel and pry bar) and am concerned that too much force might damage/crack the marble countertop. Plan is to use a new Kraus vessel sink that mounts on surface of counter top. Original plan was to remove the existing undercount sink, set new vessel sink on surface of counter that covers existing hole and then run drain line through that big area that old sink occupied. But, with old sink being firmly adhered to marble counter top, I’m thinking about creative alternatives. 1. Could try to break with hammer existing porcelain (Kohler I think) bath sink and hope no damage to counter and it actually does break and get a clean path for plumbing; or 2. Leave existing old (undermount) sink with drain plumbing in place and intact and let new vessel surface mounted sink drain into that existing old sink. Essentially, a sink draining into another sink below it. Very unorthodox without a question but trying to come up with a solution short of going for the Hail Mary of getting the old sink of the marble whether by prying or smashing with a hammer, but not damaging the existing marble countertop. So, what are the thoughts of the experts out there? If pics would help, let me know and I’ll take some and post.

 

[Nealtw]

Or use an angle grinder and cut the old sink somewhere below the stone slab.

 

[c-hans]

Or use an angle grinder and cut the old sink somewhere below the stone slab.

Well, that's an idea I had not considered. Cut, score old sink and then tap with hammer to break the main part free to clear the path for plumbing. Have a diamond blade angle saw for cutting granite, etc. Dusty for sure but might be a solution. Thanks

 

[huesmann]

I'm confused, since there are no pics. You currently have a slab with an undermount sink, and want to put a vessel sink on the same slab instead? Are you planning a semi-recessed vessel sink? Is the new sink larger than the old, and the same shape?

 

[c-hans]

I'm confused, since there are no pics. You currently have a slab with an undermount sink, and want to put a vessel sink on the same slab instead? Are you planning a semi-recessed vessel sink? Is the new sink larger than the old, and the same shape?

Correct. New vessel sink on top of existing countertop. New vessel sink will sit entirely on countertop (not semi-recessed) and covers the hole of old sink. I have posted pics to make it clearer.

 

[huesmann]

Ah, so your new sink will completely cover the old hole.

You look to have a front lip under your slab—slab front looks thicker than the slab around the sink.

Are you planning to remove the sink and slab to perform the surgery, or cut in place?

 

[c-hans]

Originally I was hoping the undermount sink was attached with hardware and silicone so that I could drop it out easily and then connect the new sink to the existing waste line. But, no hardware holding it place; looks like existing undermount is held firmly in place by an epoxy or similar. It's on there. I tried tapping a chisel around the edge of the underside edge of the existing sink but there is not a lot of swinging room to get a hard strike on the chisel to get it between sink and counter and concerned that too much hitting or prying might crack the marble countertop.

Trying to come up with a way to get old sink out of there, but also wondered if I could leave old sink in place with its waste line still attached to the plumbing and let the new vessel sink drain into the old sink below it and then water goes down drain of old sink? Not ideal of sure but it's a thought I wanted to get feedback on in addition to ideas on how to remove old sink. It's a powder bathroom. Don't want to remove the counter top from top of cabinet to get sink out of there. Seems like that rarely goes well.

 

[rjniles]

Every one I know with a vessel sink hates them. But if you must, use an angle grinder with a masonry disk to cut away enough of the old sink to clear the new strain. No need to cut it all away. Do not just drain the new into the old, it will build up mold and stink.

 

[MTN REMODEL LLC]

AS RJ says...you can cut that right from the top of the cabinet....just enough to get your drain thru.....I'm not sure I would use a grinding stone and probably use a diamond blade...?

I disagree with RJ in some respects, as I've used vessel sinks in my own homes and in invetsment/flip homes IN THE POWDER ROOM ONLY.

I've found buyers do love them....but equally, I've seen homes with them in the bathrooms and can't imagine anyone liking them in a utility type application.

( I think I've run into a similar type of your existing sink. I had a property with an integrated granite sink in the same granite as the countertops. The sink had been fashioned and glued together to make the sink and then glued to the counter undermounted....looked almost like one piece and beautifull.

I'd never seen that and sort of could not believe it. Had a small leak/ separation and had to go to special stone supplier and buy this "stone glue".
Was strong as all getout.)

 

[huesmann]

Totally go with the diamond blade. Have a pitcher of water and a 5-gal bucket underneath, and you can dribble water in the cut area while you cut. Lube and cooling for the blade, and less dust. There'll be some mud slung about, but that's easier to clean up than dust which gets everywhere.

 

[c-hans]

As a follow up to this thread (for others that might face a similar situation), I tried to use a razer blade knife to cut the caulk both from the inside edge of the bowl where it meets the marble countertop and the undercounter edge of the bowl at counter top within the cabinet. I used some caulk remover to loosen the caulk and got good cuts deep into the caulk holding the bowl but it was difficult to get all the way through the thickness. Patience wained and I tried a thin but stiff chisel to see if I could get it to start to seperate. Well, that ended up cracking the existing bowl so out came the hammer with some light taps at the cracks the bowl gave way to breaking into pieces with careful taps. Not ideal and risky to the counter top but it worked out in the end.

 

[huesmann]

It'll be a much cleaner install of the new bowl too.