Install A Bathroom Undermount Sink In Granite

Installing an undermount bathroom sink in a granite countertop requires precision, accuracy and proper mounting techniques to keep it from separating from the underside of the countertop and falling into the cabinet below. In addition to the mounting hardware that comes with a retail undermount sink kit, you will need epoxy caulk to solidly secure the sink to the granite. Installed properly, an undermount sink attaches to the underside of the countertop, allowing the counter surface to serve as the sink basin's lip and streamlining the counter surface. To install this sink right, assign a helper to hold the sink while you attach the clips to it.

Instructions

1. Measure the width of the sink's cutout and cut a length of 2-inch-by-4-inch lumber slightly longer in size using a handsaw.

2. Wipe the lower side of the granite counter with a dry cloth to remove accumulated dirt or debris that can prevent the epoxy from establishing a strong bond.

3. Apply an even layer of silicone caulk around the upper edge or the lip of the undermount sink. Spread the caulk evenly so it covers the entire surface.

4. Grasp the undermount sink and raise it with its caulked lip centered into the opening in the granite counter. Push the sink against the underside of the countertop.

5. Place the 2-inch-by-4-inch lumber over the sink cutout in the top of the countertop, directly across the sink cutout. Push an end of a bar clamp into the sink's large drain hole and the other end over the 2-inch-by-4-inch lumber. You will need two bar clamps for a sink with two bowls, using one for each drain hole.

6. Tighten the clamp partially so it holds the undermount sink in place. Ensure the reveal of the sink is even all around the cutout in the granite countertop before you fully tighten the clamps.

7. Drill holes into the lower surface of the countertop to accommodate the mounting bolts provided with the undermount sink kit. Refer to the sink's installation manual for the location of these bolts holes.

8. Prepare the two-part epoxy according to its label directions. Apply the epoxy to the bolt posts attached to the undermount sink's lip. Press the bolts into the holes you drilled. Slide the metal clips provided with the sink over the mounting bolts and the sink's edge. The instruction manual specifies the number of clips you need and their locations.

9. Tighten the bolts that hold the clamps in place and allow the epoxy and caulk to cure for the time specified on the label directions. However, do not overtighten the bolts; simply ensure they are snug. The silicone caulk combined with the two-part epoxy will hold the undermount sink firmly in place. Remove the clamps the next day and install the plumbing.

Tags: undermount sink, 2-inch-by-4-inch lumber, sink cutout, underside countertop, counter surface, drain hole