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How to Attach a Stainless Steel Under Counter Sink to Granite

Charin Deya

Undercounter kitchen sinks provide a complementary pairing for today’s modern granite countertops. If installed correctly, an undercounter sink will provide a lifetime of leak-free service. The key to a successful installation is patience.

An undercounter sink enhances the look of a granite countertop.

The high-strength epoxy and silicone caulk used to attach the sink to the granite must be given sufficient time to dry and cure before you hook up the drains and use the sink.

  1. Clean the underside of the granite surface to remove any dust or debris left over from the cutting process. Dust will interfere with the bonding action of the epoxy and silicone caulk.

  2. Apply a continuous bead of silicone caulk around the underside of the opening in the granite countertop.

  3. Lay a 2-by-4 piece of lumber across the top of the opening in the granite countertop.

  4. Press the sink against the bottom of the granite countertop and hold it for at least 30 seconds to allow the caulk time to begin adhering. Maintain pressure on the sink from below during the next step.

  5. Insert a bar clamp through the drain hole in the sink and attach it to the 2-by-4. If the sink has two drain holes, use a second bar clamp for even pressure. Partially tighten the clamp enough to hold the sink in place.

  6. Adjust from the top to ensure the sink is oriented properly on the granite. Fully tighten the clamps once the sink is seated correctly.

  7. Install the bolt posts and sink clips to the underside of the granite using high-strength epoxy. Wait 10 minutes for the epoxy to set before attaching the clips.

  8. Allow the caulk and epoxy to set for 24 hours. Install the drain pipe and other plumbing fixtures.