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How to Install Undermount Kitchen Sinks Like a Pro

Undermount sinks are one of the most used types of kitchen sinks. They’re sleek and cool, which makes cleaning the countertops easier. Whether as a replacement or a new one, installing is one of the simplest ways to add more style. It also adds personality to your kitchen.  Since undermounts are attached to the underside of countertops, they can be a little tricky to install. 

Before you bring a professional to do this project for you, it's wise to read this article first. This article provides a step-by-step guide for you to follow on how to install undermount kitchen sinks on your own. This also aims to provide you with tips on how and what you should prepare before the installation to ensure a smooth installation process. 

Tips for Preparing for Installation

Whether you’re replacing an old sink with a new one or you’re adding a completely new kitchen sink, there are some necessary steps you should take to prepare. For a pro-like process, make sure to take note of these tips: 

  • If you have an old sink, take a detailed look at its current setup to know if the before-installed sink has been done.
  • Check all the configurations in your old sink, such as mounting clips, adhesives, and so on. If you prefer, you can take pictures for reference.
  • Prepare buckets and absorbent rags to avoid mess while working with plumbing fixtures.
  • Make sure your chosen kitchen sink material is suitable for the countertop you have.

How to Install Undermount Kitchen Sinks in 10 Steps

If you’re ready to install your new sink, here’s a step-by-step procedure on how to: 

1. Choose a Spot for Your Sink

Assuming you’re working with a new kitchen countertop, this is the first step you need to take. Determine where you want to install your sink. This can depend on many factors, like the location of your kitchen’s water supplies. 

On the other hand, if you’re working on replacing an old sink or on a pre-cut countertop, measure the existing hole to determine the right size of sink you need. You can get the same size as your old one, depending on your preference. 

2. Select a Reveal Style for the Sink

The reveal style describes how much the sink’s rim stays visible after installation. This is important both for appearance and cleaning. There are three reveal styles you can choose from:  

  • Positive Reveal: About half of the rim stays visible and exposed, making it prone to get dirty like a regular drop-in sink. 

  • Zero Reveal: The edges of the countertop opening are flush with the sink’s openings and walls. This gives off a professional look and doesn’t leave extra spaces for dirt to slip into. 

  • Negative Reveal: The countertop extends past the sink walls, completely hiding the rim under it. This overhanging countertop style makes the edges prone to get dirty and hard to clean. 

Depending on your preferences, you can choose any of the three styles. But, for easier installation, use, and cleaning of the sink, it’s best to recommend a zero-reveal style. This will also give your sink a more professional look.

3. Trace the Sink

Again, assuming you’re working with a new sink and countertop, use the sink to outline the countertop. Flip the sink over and trace around it using a pencil or any marker available. Then, measure the width of the sink’s rim. This is commonly about ⅜ inches or 0.95cm wide; use that measurement to add a second outline inward to your original trace. After that, erase the original shape you traced so you don’t accidentally cut it.

 4. Cut Over the Countertop

Once you know the cutting outline, start cutting it with a circular saw or a jigsaw. Use the correct type of saw based on your countertop’s material. For instance, you need a circular saw with a diamond-coated blade if you have a stone countertop. Make sure to put on safety gear as well. If you don’t have the right equipment, you can hire a countertop fabricator to cut it so you do not damage your countertop. 

5. Position the Sink in the Center of the Hole

Before attaching the sink to the countertop, make sure it’s centered in the middle of the hole that you cut. As you position it, you can use supports to make sure that it’s in the center, like wood or a stack of boards.  

If you’re going for a zero reveal style, align the sink’s rim with the cud edges of the countertop. For other reveal styles, it might take some extra time to make sure it’s in the center and is even on all sides. Measure the distance from the edge to the rim to help you with that. 

6. Add Silicone to the Sink’s Rim

To start the actual installation, once you’re sure that it’s positioned correctly, add fresh silicone to the rim. Use a caulk gun to apply a consistent bead of adhesive to the entire rim. Once added, set the sink by carefully lifting it up to the underside of the countertop. 

As you do so, make sure that you’re keeping the position correctly. To make sure, have a second-person eye and check it for you as you lift it. 

7. Clamp the Sink to Set It

Use a clamp to attach the sink to the countertop permanently. Place a longboard or wood across your countertop on top of two folded towels. Insert the bar clamp through the drain hole and secure it to the board or wood. Add a smaller wood on the underside of the sink as well. This is to completely clamp the sink down without damaging it. 

Remember to tighten the clamp until it’s holding the sink in place firmly. Once tight and rightly positioned, leave it to let the silicone dry. If you want to make any adjustments, do it before it completely dries. 

8. Attach the Mounting Brackets

Aside from the applied silicone, the mounting brackets or clips will secure the sink tightly to the countertop once the clamp is removed. Attach and secure the brackets or clips using a ratchet without moving the sink. There also shouldn’t be any gaps between the sink and countertop. If there are, the brackets may not be tight enough. 

9. Clean the Site and Let Dry

Use denatured alcohol and a clean rag to clean the sink and countertop. Wipe away any excess silicone that might have oozed out while clamping the sink. Make sure to do this before the silicone completely cures and dries, as it would become difficult to clean then. Once clean, leave the project to dry and wait at least 24 hours before removing the clamps. 

10. Attach and Connect the Fixtures

For finishing touches, install the fixtures and appliances of the sink. These include the drain, faucet, and so on. Connect the sink to your plumbing to show a connection with the water lines to complete the setup. Once this step is finished, your sink is ready for use.

Conclusion

An undermount sink is one of the best sinks to install in a kitchen. Whether you have experience in doing so or not, learning how to install undermount kitchen sinks is rather easy with the correct instructions. Make sure to prepare and take all the steps during the installation. This way, you can ensure that you can enjoy your new sink to the fullest. 

If you still haven’t found the perfect sink, check out our undermount sink collection. We offer different kinds of undermount sinks made from high-quality materials that can complement any kitchen style and needs!