Kitchen Cabinets

How To Install Undermount Sink

By May 23, 2024 No Comments

An undermount sink is popular in bathroom and kitchen designs. Such a sink type not only provides a distinct, seamless look but also creates uninterrupted counter space and is easy to maintain. Unlike drop-in sinks, these undermount sinks are attached to the underside of countertops, making their installation more complex. Are you considering switching out your standard sink for an undermount option? With the appropriate tools and a bit of knowledge, you can handle this project on your own. This step-by-step guide will provide instructions to help you accomplish the task like a pro.

1. Setting Up Your Workspace 

Before it’s installed on the base cabinets, an undermount sink must be attached to the countertop due to the limited space inside the sink base cabinet. In those cases, when you are considering installing the sink with the countertop already in position or resetting an existing undermount sink that has separated from the underside of the counter, you are required to cut into the cabinet sides to access the clip fittings that secure the sink against the underside of the counter. The following is a list of necessary tools and materials that you must gather before starting with the undermount sink installation process: 

  • An undermount sink
  • Countertop template
  • Drill and drill bits 
  • Screwdriver
  • Adjustable wrench
  • Caulk
  • Epoxy adhesive
  • Masking tape
  • Clamps 
  • Towels to clean

2. Measure and Mark

If you want, you can measure the dimensions of the sink you already have. Remember, it can provide a starting point for selecting a new one. Or, consider using a measuring tape or a ruler to ensure accurate placement. In those cases when you plan to change the depth of your sink, avoid opting for the one that is too deep for your cabinet. To measure your undermount sink size, make sure to consider the following steps: 

  • Measure the length from the outside edge of the rims 
  • Define the width from the front to the back
  • Gauge all four sides across the rim or lip of your sink
  • Ascertain the depth of your sink from the underside to the top of the rim

3. Cut the Countertop (if necessary)

Determine the desired location for installing the sink and don your safety gear, including a dust mask and goggles, to prioritize your safety throughout the process. Next, select the suitable jigsaw and carefully make the holes along the traced outline. Bear in mind that it’s vital to provide your countertop fabricator with precise measurements of your new sink. This ensures a smooth and accurate fit. When tackling stone, be sure to have a circular saw outfitted with a diamond-coated blade for cutting. For materials like laminate, go with a jigsaw fitted with a specialized laminate-cutting blade.

4. Spread Silicone Caulk Around the Countertop

Turn the sink upside down and carefully apply a generous amount of silicone adhesive along the edge of the sink. Ensure the adhesive is evenly spread. Opt for a waterproof silicone caulk from a canister. Tightening the clamps raises the sink so it presses against the caulk. Recheck the sink’s positioning. Adjust it before the caulk solidifies. When you’re satisfied with the sink’s placement, leave it clamped in place so the caulk has a chance to cure. Make any needed adjustments now. Once the caulk solidifies, moving the sink becomes much more difficult.

5. Install the Sink Clips

Fit a clip over a stud, then tighten it with a wingnut. Position each clip so the slotted end is over the stud and the solid end is underneath the sink’s rim. Rotate the wingnuts clockwise to tighten them. When the sink clips are properly installed, they firmly secure the sink to the countertop.

6. Clean Up Excess Adhesive

Wipe off any excess silicone adhesive that may have extruded from underneath the sink. Cleanse any smudges or residue using a damp cloth or sponge. Allow the silicone adhesive to cure in accordance with the manufacturer’s instructions. Typically, this process takes approximately 24 hours, during which it’s advisable to refrain from using the sink.

7. Test for Leaks

Activate the water flow and meticulously examine the sink and plumbing connections for any indications of leaks. Tighten any fittings as needed to ensure a watertight seal. Congratulations, You’ve successfully installed your undermount sink. Now, you can enjoy its sleek design and easy-to-clean surface for years.


Though installing an undermount kitchen sink demands time and effort, with the right tools and attentive detail, it becomes a manageable DIY project for most homeowners. Adhering to these meticulously outlined steps will empower you to accomplish a professional-grade installation, improving the visual appearance of your kitchen or bathroom. For those who prefer a professional touch or need specialized assistance to ensure the best outcome, CozyHome is here to help. Contact us to achieve the ideal finish for your project!