Who Do I Hire When I Need My Undermount Sink Repaired?

Candace Nelson
Written by Candace Nelson
Updated November 23, 2021
Woman filling water bottle in kitchen sink
Jessica Peterson/Tetra Images - stock.adobe.com

A countertop specialist can keep an undermount sink from slipping

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Sleek undermount sinks give the kitchen a seamless look and make it easy to sweep crumbs off the counter instead of trying to launch them up and over the sink’s lip. Undermount sinks are attached to the counter from underneath instead of being dropped into a hole on the counter and secured to the countertop with a lip. A common issue with the undermount design is that they can be prone to sagging over time. When the sink starts pulling away from the countertop, leaving a gap, it needs to be hiked back up and secured in place.

Undermount sinks work best with solid granite, marble, or concrete counters. This sink style is more likely to pull away from laminate and tile countertops. If your undermount sink starts to detach from the counter, here’s who you can call to get repairs made.

Benefits of Hiring Countertop Pro for Undermount Sink Repair

A countertop specialist can assess the situation and determine the best support system for your saggy sink. For example, an undermount sink shouldn’t be attached to countertops less than three-fourths of an inch thick with screws. Drilling metal brackets into thinner countertops could cause cracks. 

Benefits of hiring a countertop pro to help you with an undermount sink repair include:

  • Deep knowledge of countertop materials and what they can support.

  • Access to the right tools to make cuts or drill holes without cracking the stone.

  • The experience necessary to install the sink securely the first time.

Be sure to ask if the specialist will reattach the plumbing after setting the sink. Some don’t, which means you might need to enlist a professional plumber as well. Installing a sink shouldn’t take more than an hour or two, assuming the countertop specialist doesn't run into any problems. The average cost to have this sink repair made is around $200.

Can I DIY Undermount Sink Repair?

If you feel comfortable handling advanced DIY projects, you can secure an undermount sink yourself. You’ll need a willing partner to lend an extra set of hands. 

If you have a heavy undermount sink, like ceramic models, install an undermount sink support ($100) to keep gravity from pulling your dishwashing station down. Silicone caulking isn’t going to be enough. Remember, the mount also has to support the weight of the garbage disposal, pipes, and a stack of dirty dishes.

You can support an undermount sink with a combination of metal supports, plywood frames, clips, and silicone caulking. Sometimes installers use particle boards to support undermount sinks. This isn’t the best choice, though, because particle boards are vulnerable to moisture.

Fill in the Gaps

If you just need to fill in a gap between the counter and the undermount sink, use silicone caulking to get the job done. For about $5 per tube, you can get a nice, watertight seal.

Here’s how to apply the silicone caulking:

1. Turn off the water supply to the sink and disconnect the plumbing.

2. Remove any clips and lift the sink out of the hole, and set it aside. You might need to scrape any lingering caulking from the underside of the counter.

3. When the space is cleaned up, set the sink back into place with the clips and screws loosely in place. 

4. One person should hold the sink in place while the other uses a caulk gun to put a line of caulk around the sink.

5. Pull the sink up and into place through the drain hole. Have the second person tighten the screws.

6. Place wood braces under the sink until the caulk is dry (about 24 hours).

7. Reconnect the plumbing.

Can I Hire a Plumber for Undermount Sink Installation?

Installing a sink is no small task, so you may want to hire a plumber to ensure it’s connected properly and leak-free. Plumbers charge between $45 and $200 per hour on average. Installing a sink only takes about an hour. 

Since a sink is something you use frequently, it might be worth the cost to hire a professional to ensure everything is watertight and secure. No one wants to be forced to improvise and wash dishes in the bathtub because their kitchen sink started slipping. 

How Do Pros Install Undermount Sinks?

Countertop specialists will ensure your undermount sink is installed correctly. They’ll use a metal or wood brace if needed, then attach the sink with epoxy adhesive. Finally, they’ll use silicone caulking to seal it up tight.

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