DIY Network

How to Install an Undermount Kitchen Sink

Your undermount sink combines beauty and convenience. Just wipe debris right into the sink.

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undermount kitchen sink gives clean lines to space


Step 1: Have a Professional Cut a Hole

Before beginning, have a professional fabricator cut the sink hole using a template. Sink bowls come in varying sizes and arrangements so you can select the configuration that best meets your needs. Think about your fixtures too. Do you want a double-handle or single-handle faucet? What about a soap dispenser? Since the weight of the sink is supported from the underside, you'll need a solid surface countertop such as granite or marble.

have a professional cut sink hole in countertop

Step 2: Test Fit the Sink

Place a 2x4 across the countertop, clamp the sink to the underside and adjust the placement. Thread the wing nuts onto the screw heads. Test fit your sink and mark the location for the mounting clips. With the sink out, drill 1/4" holes for the brass inserts and tap them in. Clean the ridge with denatured alcohol. Run a bead of silicone sealant around the edge, and re-clamp the sink in place.

clamp sink to 2 X 4 across countertop and adjust

Step 3: Secure the Sink Bowl

Thread the wing nuts onto the screw heads and tighten the screws to anchor the inserts. Hand tighten the wing nuts to secure the bowl. After removing the clamps, place masking tape across the back of the countertop and mark the layout for the faucet holes. Drill the holes using a 1-1/4" diamond coring bit. Allow it to cure overnight before installing your plumbing.

hand tighten wing nuts to secure bowl