How to Install Undermount Granite Sinks

Granite sinks are beautiful, and undermount sinks give a clean line to the counter. The combination is not only a wonderful addition to your kitchen but also easy to clean and maintain. However, the granite sink is heavy---very heavy---and if not properly supported, you can have a disaster on your hands down the road. The best method is to have professional granite countertop installers install the sink before they install the entire counter. But if the counter is already in place, there is a way to install the sink with a worry-free future.

Difficulty: Moderate

Instructions

Things You'll Need:

• Wire brush
• Sponge
• Denatured alcohol
• Measuring tape
• 2-by-4 inch framing lumber
• Saw
• Pneumatic nailer
• Framing nails
• Silicone caulk/adhesive
• Bar clamps
• Hammer
• Shims

1. Clean the areas of the sink and countertop that will be sealed together. Brush them off with a wire brush and then clean with a rag or sponge and denatured alcohol. It is important to clean this area well, or the adhesive will not adhere well.

2. Measure around the underside lip of the sink. Use these measurements to build two frames with 2-by-4 inch lumber. One frame will go right under the sink and one will go at the bottom of your cabinet. Make sure the frame under the sink lip will not interfere with any faucet plumbing.

3. Run a continuous bead of 100 percent silicone caulk and around the top of the outer lip of the sink. Place a 2-by-4 board, longer than the opening in the countertop, across the opening. Put the sink in place and while you are holding it, have someone slip a bar clamp through each drain hole and clamp the sink in place from the board to the bottom of the sink. Check that the sink is centered. Adjust if necessary.

4. Place the frames in the cabinet and have someone hold the top on in place. Measure the difference between the top and bottom frame. Cut four pieces of 2-by-4 inch board to that measurement.

5. Use a pneumatic nailer to nail the four posts to the corners of the frame inside the cabinet. The posts should be tight to get in; you should need to knock them in with a hammer.

6. Remove the clamps after 24 to 48 hours. If you feel the frame is not tight, place shims under the bottom evenly to push it up even more. Trim off the excess trim.

[aajohnson21]

on 6/26/2009 Nope... too much work. Silicone alone will do the job. Where are you people getting your intel from?