How to Install Undermount Kitchen Sink Properly

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Need to install an undermount sink in your kitchen?

You’ve come to the right place!

Attached to the underside of a counter, undermount kitchen sinks add a cool, sleek look to your kitchen décor. Since there are no exposed edges around the basin to catch grease and food bits, these sinks make it easier for you to clean and wipe the surface of the counter.

However, they’re also a bit more difficult to install than drop-in models. 

But don’t worry because we’re here to help! 

Keep reading to learn how to install an undermount kitchen sink properly.  

What’s In This Guide

This guide explains a proven 7-step method to remove your old undermount kitchen sink and install a new one. We also provide a list of the tools and materials you need to complete the task.

Finally, we answer some of the most frequently asked questions about installing an undermount kitchen sink. 

However, if you still have any queries, please leave us a comment below!

Why Install an Undermount Kitchen Sink

How To Install Undermount Sink

Installing an undermount kitchen sink is a simple yet excellent way to add a fresh, sleek feel to your kitchen. Unlike drop-in sinks, these units don’t have a visible crevice, lip, or rim to catch dirt, making it easier for you to clean the counter. 

Undermount kitchen sinks offer a bit more counter space as well.

The Process

Installing an undermount kitchen sink is a bit difficult and will take you around 20 to 30 minutes (or more if you’re doing it for the first time).

It takes two people to remove and install an undermount kitchen sink, so make sure you have someone to help with the heavy lifting.

In order to install an undermount kitchen sink properly, you just need to follow these steps:    

  1. Turn off the water supply
  2. Remove your old sink
  3. Prep the surface
  4. Position your new sink
  5. Add wooden blocks
  6. Secure the sink
  7. Make the final touches

Get Prepared: What You’ll Need:

The supplies and tools you need to install an undermount kitchen sink include:

  • Utility knife
  • Scraper
  • Cleaning gloves
  • Silicone sealant
  • Mallet
  • Mounting hardware
  • Denatured alcohol
  • Wooden block
  • Sink drain
  • Cleaning rag
  • Bucket
  • Epoxy

Step 1: Turn off the water supply

How To Install Undermount Sink

Before you remove your old sink, it’s advisable to take a couple of pictures of your drain setup for reference. Turn off the water supply and disconnect all the plumbing fixtures.

Place an empty bucket under the pipes and fixtures to collect any dripping water or use a cleaning rag to clean away any excess water. If you own a garbage disposal unit, switch off its power, disconnect it, and remove it from the sink as well.

Step 2: Remove your old sink  

Most undermount kitchen sinks are fixed to the countertop with metal clips and silicone sealant. Cut through the sealant with a utility knife, unscrew the clips, and then remove your old sink.

If you’re also planning on replacing the faucet, make sure you do it after this step, as you’ll have easy access under the sink.

Step 3: Prep the surface

How To Install Undermount Sink

Use a razor scraper to remove the remaining silicone sealant. Make sure you work carefully and don’t damage the countertop while completing this step.

Use mineral spirits or denatured alcohol to clean the rim of your new sink, as well as the underside and topside of the countertop. Remember to wear cleaning gloves to protect your hands when handling these products. Make sure you also follow the manufacturer’s instructions for proper and safe disposal.  

Step 4: Position your new sink

How To Install Undermount Sink

Position your new undermount sink in the cabinet under the cutout and apply a thick layer of silicone sealant along the edge. While one person holds the sink to the countertop, the other person should check if it’s positioned properly.

Step 5: Add wooden blocks

Place a piece of wood vertically between the underside of the sink and the bottom of the cabinet. If the wooden block is too short, keep adding shims until it fits snuggly between the two surfaces.

You can use a mallet to gently tap the block into place. The wood will hold your undermount sink in place until the silicone hardens properly.

Step 6: Secure the sink

Once the sink is secured into place, attach the mounting brackets. These brackets come in several different styles. You can attach the bar clamps to the countertop with epoxy or a drill, depending on the style.

Make sure you choose a mounting bracket that works best for your needs.

Step 7: Make the final touches  

How To Install Undermount Sink

Once you secure your sink in place, wipe away any excess and visible silicone with a damp cloth. Wait at least a day or two for the silicone sealant to dry before removing the wooden block.

Install the sink drain and hook up your undermount sink to the plumbing. 

Lastly, reattach the fixtures you removed from your old sink.

Frequently-Asked Questions About Installing an Undermount Kitchen Sink

Can I install an undermount kitchen sink after setting the countertop in place?

If you’re building a new kitchen, it’s important to install your undermount kitchen sink before fixing the countertop slabs in place. Once you secure the countertop slabs, you won’t be able to fit the sink in the hole or properly seal it to the underside of the countertop.  

How do I attach an undermount sink?

You can attach an undermount kitchen sink with a two-part epoxy adhesive and seal it to the countertop by applying silicone caulking around its perimeter. 

If you’ve never installed an undermount kitchen sink, it’s better to hire a professional or take help from someone who knows their way around sinks.

What is the average cost of replacing an undermount kitchen sink?

It will cost around $150 to $200 to replace an undermount kitchen sink. However, this range does not include the cost of a new sink. If you’re going to purchase a new sink, it will cost you a total of approximately $400.

2 thoughts on “How to Install Undermount Kitchen Sink Properly”

  1. Everything is very open with a really clear clarification of the issues. It was definitely informative. Your website is useful. Thanks for sharing!


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