Can an Undermount Kitchen Sink Be Installed Without Replacing Corian?

Corian, the manufacturer DuPont's brand name for a type of solid surface countertop, blends durability with beauty. It is waterproof, stain-resistant and is crafted in a dazzling array of colors and styles. Due to its longevity and value, some homeowners wish to keep their Corian counters and replace their existing self-rimming, overmount sink with a new undermount sink. Corian is the perfect countertop material for an undermount sink, as the material accepts screws and glues well and sports a lovely finished edge along the sink line.

Vegetables on the kitchen counter
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A new undermount sink can fit in existing Corian, under certain conditions.

The Sink Hole

The new undermount sink must fit into the existing sink hole. If the sink hole is too small, a new, larger hole is easily cut with a jigsaw. If the hole is too large or oddly shaped, the undermount sink will not fit. Fortunately, sink manufacturers create a vast selection of sinks in all sizes and shapes, so chances are an undermount sink will fit within the existing hole. If the hole is an unusual shape or size, however, it may take a consultation with a Corian dealer to locate the perfect sink. The Corian dealer can offer suggestions and submit a custom order for a specially-made undermount sink that will fit the sink hole.

Sink Support

The Corian countertop must support the new undermount sink. Filled with water and dirty dishes, a sink can easily weigh more than 100 pounds. The undermount support system must hold up a tremendous amount of weight. Some undermount sink kits contain clips and screws that secure the sink to the underside of the counter. Many contractors recommend additional support, as the clips may fail under extreme loads. Tim Carter, a contractor and real estate broker, recommends high-strength epoxy adhesive and silicone caulk. Corian material accepts adhesive well. Extremely heavy sinks, such as cast iron or stone sinks, may require a metal brace or custom wood frame under the sink cabinet. This extra support prevents heavy sinks from dropping or falling and damaging the Corian counter.

Adequate Plumbing

With a few adjustments, the new undermount sink can connect into the existing water supply and drain line plumbing system. Undermount sinks sit lower in the sink cabinet than their overmounted counterparts. Supply lines and the drain line or lines may need to be cut and rejointed to fit the new sink. Rarely does this work require replacement of the countertop, however. If the existing plumbing is inadequate or will be amended with, for example, a new drain line or vent, a good plumber will offer suggestions to prevent replacement of or damage to the Corian.

Hard Use

Corian can chip and crack under hard use. An undermount sink exposes the interior of the Corian as the Corian forms a ring around the sink. In most cases, Corian resists impacts from average sink use, but a vigorous scouring of a large metal stock pot or an errant cast iron skillet striking the counter may chip or mar the edges. Small chips and scratches are easily repaired with a mild abrasive liquid cleanser. Deeper dents and abrasions may require abrasive pad sanding or professional refinishing.