Home Plumbing How To Install Undermount Kitchen Sink

How To Install Undermount Kitchen Sink

How To Install Undermount Kitchen Sink

This past fall, I decided to give my kitchen a makeover. The centerpiece of my project was to install a new undermount kitchen sink. For years I had a Drop-in kitchen sink, which I had no complaints with, but given that I strived to make my kitchen look prettier, there was no other option than to go with an undermount sink. Read on to see how to install undermount kitchen sink easily.

Unlike Drop-in sinks, which have a standard installation technique, undermount sinks give you the flexibility to choose the look you desire for your kitchen. You can install your undermount sink in three ways, distinguished by their different reveal style.

install undermount kitchen sink
  • Zero reveal – In this style, the edge of the countertop is flush with the opening of the sink.
  • Positive reveal – Some of the sink’s rim is visible past the edge of the countertop.
  • Negative reveal – Your sink’s rim will be concealed entirely beneath the countertop

I chose to go with the zero reveal look. It provides a sleek look to your countertop, and it is the easiest to clean and maintain out of the three. But, you can choose your look, depending on your needs and imagination.

As I was caught up in the make-over groove, I also decided to buy a new countertop. This did add things to my to-do list, but it provided me with more flexibility towards re-designing my kitchen. Before I could start installing my new sink, I had to shape my new countertop.

Creating a countertop opening is an adult-level craft project. You need to place your new sink onto the countertop and trace its size to measure the size of the cut-out you need. Your outline will be slightly larger than the opening required. As a result, make a second outline about 1/2 inches smaller than the original for the hole.

Now, comes the adult part- using a circular saw, carefully follow your sink outline to create an opening. Lastly, I suggest cleaning your countertop with denatured alcohol as it will thoroughly clean the surface without leaving any residue.

Average Cost To Install Undermount Kitchen Sink Yourself

Your new undermount kitchen sink is a long-term investment. It is imperative that you buy a good quality sink from a reputed manufacturer. Additionally, buying new faucet connections or plumbing will add to your expenses. Overall, depending on the sink that you buy and the additional parts, this project will cost around $200-$500.

Time Required

Installing your undermount kitchen sink is a time-consuming project, especially if you decide to attach it onto a new countertop. It will take you a good 1-3 hours to shape your countertop, attach your new sink and its connections.

Tools & Material

Install Your Undermount Kitchen Sink

1. Installing Sink to Unattached Countertop

We recommend you install your undermount kitchen sink to the countertop before you attach the countertop to the base cabinets. This will make it easy to attach your sink clips and apply silicone sealant to the countertop.

how to install undermount kitchen sink the right way
  • Flip the countertop, so the underside is facing up. 
  • Placing your undermount kitchen sink over the hole and trace an outline. This outline will serve as a guide to install the sink clips 
  • Additionally, place the sink mounting clips at each corner at 10-inch intervals along the sides. 
  • Depending on the type of mounting clips your manufacturer provided you, you either need to drill into your countertop and install them using screws or use construction adhesive to glue the sink clip studs in place
  • If using an adhesive, follow the instructions for drying time. 
  • Along the inner edge of your outline, apply a generous coat of silicone caulk using a caulk gun. 
  • Placing the sink onto the countertop, clip it by twisting the wingnuts on the clips. 
  • Gently press your undermount kitchen sink in order to install it securely onto the countertop.
  • Wipe any excess caulk with a rag and denatured alcohol. Furthermore, allow the remaining caulk to dry for 24 hours or to manufacturer’s instructions. 
  • Turn countertop over and finish the installation.
  • Additionally, attach your faucets, garbage disposal, kitchen plumbing and other components as needed. 

2. Installing Sink to Existing Countertop

If you plan to install an undermount kitchen sink to an existing countertop, you must buy a sink that fits into your current countertop opening. You can certainly re-size the hole using a saw, but that will add to your time and cost. Remove your cabinet doors to allow easy access to your countertop

Before you begin any installation, disconnect all faucet and pipe connections. Furthermore, shut off your main water valves. Observe the underside of your countertop and remove any existing sink brackets and old epoxy using an adhesive remover or paint scraper.

In order to install your undermount kitchen sink to the existing countertop, follow these steps:

how to install undermount kitchen sink correctly
  • Install sink clips to the underside of the kitchen sink counter.
  • Place 2 x 4-inch boards underneath your kitchen sink counter to serve as a stand for your undermount sink during installation.
  • Furthermore, stack the boards on top of each and place the sink at the summit. Next, using a caulk gun, apply a generous coat of caulk around the edge of the countertop. 
  • Raise the sink, so it presses against the underside of the countertop and forms a watertight seal. Additionally, add boards as needed to ensure the sink stays in place. The idea is to hold the sink in place until your adhesive has dried off.
  • Use the sink clips to attach the sink to the counter. 
  • We advise using denatured alcohol to wipe any excess silicone sealant on the underside of your countertop. 
  • Allow the remaining caulk to dry for 24 hours or to manufacturer’s instructions. 
  • Once you are sure the sealant has dried, proceed to remove the boards.

Review Your Connections

After installing your new sink, re-install your faucet connections and all kitchen plumbing. Open your water valves and let the water flow for a few minutes. Check for any leaks from your sink, faucet assembly, and plumbing.

Frequently Asked Questions: How To Install Undermount Kitchen Sink.

Do I always need to modify my countertop for the sink to fit?

If you choose to install an undermount sink to your existing countertop, measure your opening and buy a sink that will fit exactly into it.

Which Reveal Style is the best?

There is no incorrect answer to this question, reveal styles are based on your preference. This is just a feature of the undermount sink that gives it added flexibility over drop-in sinks.


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