Installing an undermount sink: your thoughts please

[ArtKilinski]

Okay. My tile job is starting this thursday!!!

But...

I bought a precut granite countertop (37" wide) from Expo Design Center. Nice beveled edges for sink and outside edge too. Got a backsplash and sidesplash too.

Bought an American Standard undermount sink -- I believe it's porcelain or some similar material -- it's definitely not cast iron. The countertop came with an epoxy to mount the sink with. My tile guy asked where I screw in the sink clips...the countertop doesn't have any screw holes underneath to mount the sink clips.

My tile guy suggested drilling in the appropriate holes under the countertop (with an impact drill), placing the threaded ferrules in the holes, using epoxy to hold the ferrules in place. Then use the standard sink mount clips along with silicone caulk to seal the sink edges.

Whaddya all think? Have any of you undermounted a sink to a granite countertop?

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[John Bridge]

Art,

I've never mounted one, but I'm pretty certain you don't use screws or other hardware. Wish I had paid more attention now, but it's either epoxy or pure silicone. You would have to prop the sink in position while the material sets. Don't let the guy try to drill holes. It won't work and could damage your top.

Hope someone else has had some experience, but it's really a fabrication issue.

[MikeC]

I just did this, well I had someone install granite countertops and an undermount sink. We bought a Kohler cast iron under-mount sink. After removing the old countertops the installers used an undermount kit. All this is 2 rails that go from the front edge of the cabinet to the back edge. The sink then rests on this. These rails have the screws built into them. After you install the new counter-top just crawl under the sink and crank those screws up against the bottom of the sink and that pushes the sink to the bottom of the counter top. Be sure to caulk B4 you tighten up the sink. :D

[John Bridge]

Hi Mike,

Now that you've posted, it seems to me we've been there before? :D

[MikeC]

Yeah John, Been there, Done that... as they say. :D

[ArtKilinski]

I'll look into those rails...sounds like a good idea. Can these be purchased at a hardware store like a Home Depot or an Orchard Supply or Lowe's?

[MikeC]

I know that Lowes has them. H.D probably does also.

[Jason_Butler]

Hi Art,

I was doing a job recently when the countertop folks showed up. They also had a porcelain undermount sink for their granite top in the bathroom.

The installer put a bead of the epoxy around the sink and placed a 2x4 underneath just to hold it in place until the epoxy dried. 10 minutes later the sink was secured. No rails, no clips; just expoxy

Jason

[John Bridge]

That't the impression I had, too. . . that they are glued on with epoxy.

I like Mike's way better, though. Down the road when the sink starts looking old, it'll be a heck of a lot easier to remove and replace.

[PSULion92]

When you buy one of those kits from the store (granite counter, back and side splahes), do you need to put a layer of plywood on the top of your cabinet prior to installing the counter? Or does the counter just sit on the cabinet (with perhaps some caulking or epoxy?)? Thanks!!!

[MikeC]

The granite just sits on top of the cabinets. If your cabinets are level front to back and side to side you just use a clear silicon caulk on all of the exposed cabinet edges and set the granite in place. If things aren't level, well..... then you gotta shim and level everything with the granite in place and then caulk all the cabinet edges from underbeath. It's definitely a 2 man job. Or at least 1 man and 2 boys. :D

[ArtKilinski]

Home Depot doesn't carry sink mounting rails. The guy at Orchard Supply looked at me as if I was retarded when I asked him about rails. All he could say was "all of our sinks here are top mounted..."

Interesting thing...the precut granite countertops at Home Depot already have holes w/ferrules underneath for sink clips. The Expo countertops don't have the holes. The Expo countertops have a nice beveled outer and inner edge, the Home Depot version simply has rectangular edges.

I'll check out Lowes soon for the sink mounting rails and let y'all know...

I'm sure the epoxy will be fine but there's nothing like a little addes support. But I did find some thinner yet sturdy shelf mounting rails and brackets that I could probably turn into sink rails....

[John Bridge]

Art,

Make sure you're not confusing cultured marble or some other man-made product for real "granite." I can't imagine ferrals in the underside of a natural granite top.

[Unregistered]

Home Depot can special order Kohler sink undermount kits for $26.00 ea. I just did this.

[jadnashua]

The granite fabricator I've used for my remodeling puts T-shaped slots in the bottom of the slab with his diamond milling machine. The T-bolts and clips let you install the sink in the "normal" manner with some caulk and the clamps. Seems to work fine.