Undermount Sink Questions

[Jerry Bruette]

Was at a cabinet dealer today and they showed me an undermount stainless sink that was installed in a countertop with laminate. Looked like a nice setup to me. Does anyone have any experience with an undermount and laminate top?

[Steve Rozmiarek]

I had a customer want it last week because it was cheap. In my opinion, that's putting a lot of trust in adhesives and fillers at a seam you know will be wet all the time. I talked my client out of it, there are other options that don't cost a lot more than laminate that have no possibility of water getting into a water unfriendly substrate at that lip. Look into Mystera for example, you probably have the tools you need to make your own solid surface countertop out of it, and it's available to DIY customers.

[Jamie Buxton]

I had a customer want it last week because it was cheap. In my opinion, that's putting a lot of trust in adhesives and fillers at a seam you know will be wet all the time...

I'm not trying to make an argument, but rather to ask a question. In my area, the most-common approach to kitchen remodels is a stainless sink undermounted below slab stone, and it's been like that for fifteen or twenty years. Doesn't that approach have the same structure -- an adhesive between the sink and the countertop material?

[Bruce Wrenn]

It's the edge of the substrate for the laminate that's the problem. Usually it's either high density particle board, or plywood, both of which absorb water.

[Steve Rozmiarek]

Jamie, the way I know to undermount in laminate (there may be other techniques) is to cut the sink cutout in the substrate (mdf or ply) attach the sink to the sub so it's flush with the top of the sub, then fill the gap with auto body filler. Sand the filler smooth to the level of the sink, then glue the formica over everything as usual. What you end up with is a formica lip over the edge of the sink that is water proofed by the contact adhesive only past the edge of the body filler. Any water that gets in under the lip of formica and can go far enough to get past the filler, is going to swell the sub. That can happen because of a sander or glue error, which is very easy to do. I also have never seen a waterproof contact adhesive glue line.

I agree, the usual technique is undermount under stone or solid surface. That's a completely different technique, basically you just glue a sink to the bottom of an impervious to water slab of rock, no matter how wet it gets nothing will swell or fail.

Around here, quartz is cheaper than I can build solid surface (corian), both are good bargains. Natural stone is quite a lot more depending on taste of course.

[Jerry Bruette]

The dealer told me there's an insert of solid surface material bonded to the sink. I don't know if there was a brand name or not.

We're researching a kitchen remodel and I don't like stone but LOML wants an undermount sink. We didn't know if it was possible with laminate until the dealer showed us an example.

I'll check the Mystera.

[Steve Rozmiarek]

The dealer told me there's an insert of solid surface material bonded to the sink. I don't know if there was a brand name or not.

We're researching a kitchen remodel and I don't like stone but LOML wants an undermount sink. We didn't know if it was possible with laminate until the dealer showed us an example.

I'll check the Mystera.

Ahh, that would be how they profile it. I was curious, hadn't dug into it. That's a fairly new approach. I'm still not a fan because there is a glue line there still. It'd be better than the older technique because you can get rid of the bondo, but still has a water sensitive core being protected by a little glue. Lots of potential points of failure in a core with an inset solid surface piece bonded to a sink, covered by laminate.

Just skip them all and do a one piece solid surface. If you don't put a price on your labor, you'll have about the same $ in solid surface material vs laminate tops, with the solid surface being a far superior countertop. It's fun to work with too. Comes in sheets, bonds with color coded epoxy, mills pretty easily, sand to the sheen you like, and presto, seamless custom, nearly bulletproof countertop. Wood Stock Supply is my supplier, you probably have a comparable near you. Wood stock's website has the product and pricing. A sheet is wide enough for the top, an edge build up, and a backsplash. Comes in various lengths, 8' is $4-500 depending on colors.

[Mike Cutler]

I don't know that I'd particularly trust an under mount sink on a laminate. Water is going to creep in some day. Might be 20 years, but it will eventually happen.
I know it's done, but it's not for me.

I don't know about the adhesive only statement. I have an under mount sink on a granite counter top, and it is not only glued, but there are 8 threaded fasteners embedded into the granite around it. Even with the fasteners I don't think I'd fully trust an under mount on a laminate counter

[Jamie Buxton]

Karran makes a line of sinks specifically intended to undermount under laminate. The sinks have a wide resin flange, and they are bonded to the laminate with the two-part epoxy used to seam solid-surface countertop material. I'm not clear about what adhesive is used for the rest of the countertop. The body of the sink can be resin, or can be stainless steel. Here's a page on Formica's site about the technique -- http://www.formica.com/en/us/advice-and-ideas/laminate-countertops-love-undermount-sinks