Undermounted Sinks - Calgarypuck Forums - The Unofficial Calgary Flames Fan Community

red sky · 01-31-2013, 08:11 AM

I bought a new infill in 2009 and the builder skimped out on installing an under mounted sink in the kitchen. I have a large granite counter top and I was wondering how difficult it would be to have the top mounted sink replaced with an under mounted one. I checked the granite underneath the sink and it appears to have rounded smooth edges but I would not want to damage it by removing the old sink nor can I tell how symmetric it actually is. Does anyone have any experience with this?

Slava · 01-31-2013, 08:52 AM

I haven't gone from a top mount to an under-mount, but it looks like you would be able to. The only fear I would have is getting the gunk off the top of the counter that will now be exposed and making sure that you have no visible trace of the old sink being there. I have no idea how easy that would be.

My under-mount is basically held in with some strapping that was screwed into the granite and then a silicone adhesive/caulk around the edges. I would imagine that you would get someone to do this for you though and they could do that part pretty easily as long as the sink holes match up and you have enough room underneath.

red sky · 01-31-2013, 09:09 AM

Yeah, the other problem is that measuring the hole where the sink will fit will be difficult as well as finding a sink to fit the space as they generally cut the granite to fit the sink, not the other way around.

I was concerned about the gunk (silicon, etc.) but I think there are some good products like Goo Gone that could do the trick. I guess worst case scenario, I could always reinstall a new top mount sink.

red sky · 01-31-2013, 09:10 AM

Another question, would a plumber be able to handle everything for the installation and removal? I imagine so but not certain.

Rjcsjc62 · 01-31-2013, 01:08 PM

I have never tried doing this, but I feel like you are opening up a can of worms.

With a drop in sink, the hole that is cut can be imperfect to the tolerence of the size of the sink's flange. The cut doesnt even need to be straight, the cut is completely covered up by the sink itself.

What you are counting on here is, that the builder made a cut specifically for a certain size sink, and for whatever reason just put in a drop-in sink.

If the edges arent finished, or the penetration doesnt line up perfectly with an undermount sink, then your undermount sink will look far worse than the drop in sink that is there now.

However, if the conditions are perfect and you have a hole that suits a specific undermount, the install isn't too tough.

You need a block of wood longer than the width of the sink set on top of the counter, drop a rod through the centre of the wood through the outlet of the sink, and through another block of wood, that is bigger than the sink's outlet. Add some PL-400, or some kind of heavy duty adhesive to the undermount's flange and tighten the two blocks of wood until the sink is firmly in place. Leave overnight, then remove the lumber and rod.

Any silicone from the drop in sink install that is left on the top of the granite would be easily removable. It should just be a caulking, or some kind of sealant, and not really an adhesive.

Slava · 01-31-2013, 01:12 PM

Quote:

Originally Posted by Rjcsjc62

I have never tried doing this, but I feel like you are opening up a can of worms.

With a drop in sink, the hole that is cut can be imperfect to the tolerence of the size of the sink's flange. The cut doesnt even need to be straight, the cut is completely covered up by the sink itself.

What you are counting on here is, that the builder made a cut specifically for a certain size sink, and for whatever reason just put in a drop-in sink.

If the edges arent finished, or the penetration doesnt line up perfectly with an undermount sink, then your undermount sink will look far worse than the drop in sink that is there now.

However, if the conditions are perfect and you have a hole that suits a specific undermount, the install isn't too tough.

You need a block of wood longer than the width of the sink set on top of the counter, drop a rod through the centre of the wood through the outlet of the sink, and through another block of wood, that is bigger than the sink's outlet. Add some PL-400, or some kind of heavy duty adhesive to the undermount's flange and tighten the two blocks of wood until the sink is firmly in place. Leave overnight, then remove the lumber and rod.

Any silicone from the drop in sink install that is left on the top of the granite would be easily removable. It should just be a caulking, or some kind of sealant, and not really an adhesive.

I didn't think of that, but that's a great point. The edges of that aren't going to be polished and it will look terrible.

red sky · 01-31-2013, 02:37 PM

It is really hard to tell even with poking my head under but it does appear that it is smooth and polished. I am not sure if they were going to put in a larger undermount sink and then decided against it. Ultimately, it is probably opening up a can or worms as suggested. Thanks for the responses.

surferguy · 01-31-2013, 05:04 PM

Id have a granite company come out and take a look if you are considering it. Let me know if you want a contact and I can put and name in your hands.

topfiverecords · 01-31-2013, 05:43 PM

If you're really committed to the idea, I'd pull the drop in sink just to see what the situation is. At worst you have to clean up the old silicone and reinstall the drop in. If the granite was cut/polished for an undermount, you'll for sure be on a hunt to find a size to match. It's all possible though.

sun · 01-31-2013, 06:05 PM

Agreed. Pull it off and see what you're dealing with. If the edges are polished (kinda doubt it), go for it. If not, throw the sink back in and forget about it, IMO.

red sky · 01-31-2013, 08:54 PM

I can see and feel the edge from underneath and it is definitely polished. It is 29" wide which seems to be a somewhat standard size. It is difficult to get the depth however but it may be a project for a long weekend. Do most places have lots if inventory or is it something that would have to be ordered?

Slava · 01-31-2013, 10:51 PM

Mine was ordered and took about 3 days or so.

Methanolic · 02-01-2013, 08:51 AM

Quote:

Originally Posted by red sky

I checked the granite underneath the sink and it appears to have rounded smooth edges but I would not want to damage it by removing the old sink nor can I tell how symmetric it actually is. Does anyone have any experience with this?

I used to work for a granite company here in Calgary and we would stock several different sizes and styles of kitchen sinks as well as bathroom basins. Every sink we stocked had a template to match. There are two ways to go when cutting, negative or positive...granite overhanging the sink or granite set back to expose the stainless sink top.

I would suggest you disconnect the plumbing, remove the sink (silicone can be razored off and a final clean with acetone) and then lay some card stock over the hole and trace the outline. Cut out your template and take it to any granite shop in town that stocks sinks. They will compare your template to theirs and once they find a comparable size and shape they will be able to tell you exactly what make and model of sink you need (depending on your preference of reveal) and likely sell it to you cheaper than home depot etc.

Regarding installation of the new under mount sink I would definitely recommend that you get a granite company to install it. They will likely tell you to hold off on reconnecting the plumbing for 24 hrs to allow the epoxy to fully cure.

Hope this helps.