38 undermount kitchen sinks from Franke (13), Blanco (11), Dayton (5), Elkay (5), Rohl (2), Moen (1) and Shaws (1), running 16-1/2" through 36" in 18 and 19 gauge stainless, granite composite, quartz and fireclay.
The countertop decides whether an undermount is possible at all. The sink hangs from the underside of the top, so the cut edge of the counter is exposed and has to be a material that can be polished and sealed — stone, quartz or solid surface. On laminate the particleboard core sits open at the cut and swells at the first splash. If the counter is laminate, the sink has to be drop-in or dual-mount instead.
On stainless the gauge number runs backwards: 16 gauge is thicker than 18. Eighteen is the practical floor for a kitchen bowl — thinner than that and the bowl drums under a disposal and dents under a dropped pan. Sound-deadening pads and undercoating on the underside matter as much as the gauge on the spec sheet.
Granite composite is quartz dust bound in resin — Blanco calls it Silgranit, and the Franke Peak and Maris bowls are the same idea. It hides scratches and water spots in a way brushed stainless does not, and it comes in colour rather than only in steel. Fireclay is ceramic fired onto a clay body: the hardest surface stocked here and the heaviest, which matters because the cabinet has to carry it.
Bowl layout is the other decision. A single bowl takes a sheet pan flat. An equal double splits washing from rinsing. A 1-3/4 gives one large bowl and a small one over the disposal. A workstation sink — the Franke Culinary Center here — carries an integrated ledge that takes cutting boards, colanders and drying racks over the bowl, which buys back counter space in a small kitchen. Bar and prep bowls run 16-1/2" to 23".
Reveal is set when the counter is templated, not at install, and the counter shop does it rather than the plumber: positive reveal leaves a strip of the sink rim showing, zero reveal brings the counter edge flush with the rim, negative reveal undercuts so the stone overhangs slightly and wipes clean into the bowl. The sink is mounted to the underside of the top with clips and epoxy before the top ever reaches the house.
ADA-compliant shallow bowls are stocked in the Elkay Lustertone line, and laundry and utility bowls in the Blanco Stellar and Rohl Allia.
Related: undermount bathroom sinks, drop-in sinks for laminate tops, apron-front and farmhouse sinks, basket strainers, disposals and the full kitchen range.
