How to Install and Replace Under Mount Sink – Fully Step by Step Guide


The under-mount sink has gained popularity with homeowners because of the natural cleaning capabilities and the variety of designs and styles. Therefore, many homeowners want to install an under mount sink in granite, quartz, or wood granite. Many also want to find ways to replace the sink under mount if it’s broken or damaged. If you’re one of those searching for answers to these questions, then you’ve come to the right spot. We have put together step-by-step instructions on how to install and replace under mount sink.

How to install an under mount sink

While under mount sinks appear to outshine gravity, they are very similar to installing instead of high mount ones. Clips for mounting that keep the sink securely against the countertop are concealed under the counter. For granite countertops, the bolt portion of the clips is permanently bonded to the stone using strong epoxy. You shouldn’t require new hardware. Shut off the water source and disconnect the pipes before replacing the sink or hiring an experienced plumber to install it for you. The sink is out of service for at least 24 hours because of adhesive set-up time, so be prepared. We can’t explain how to install and replace under mount sink so first we will explain how to install an under mount sink step by step.

Read more: How to install drop in sink on granite countertop

Step 1

Before attaching the clip to the sink under mount, It is essential to equip the sink with adequate support to ensure it can stand against the countertop. You can choose to use either pine or fur to support the sink. To do this, you must determine the length. After that, you can employ a handsaw to cut the fur or pine into a proportion of one-by-two to support the sink under mount.

Step 2

Also, you must ensure that the under mount sink is perfectly attatch to its countertop. It is essential to apply silicone caulk or sealant on the top part of the sink’s rim.

Step 3

Place the countertop of the sink’s underside against the edge in the basin. Then, you must put the supports that you cut onto the bowls in the sink under mount. Then, you have to adjust the sink to perfectly align with the edge and the rim on the counter.

Step 4

Then, you can place your clips equally with the aid of a screwdriver or an adjustable wrench. Once you’ve positioned several clips, take them off the support to place the remaining clips. After setting up the clips, successfully install yours under mount sink. Congrats, bud.

How to replace under mount sink 

Replacing an under mount sink is a fantastic DIY project that will save you money in a short amount of time. Now, we will explain how to replace the under mount sink. 

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Step 1

If you are planning to replace your old sink under mount with the new one, it’s important to determine the size of the new sink in the order it can fit in the sinkhole that is already in place. This will ease the burden since you don’t need to cut off the extra portion of the new sink.

Step 2

The next step is to make a watertight seal between the sink and countertop. For this, you need to apply a caulk line along the sides of your bowl. This will link the countertop with the bowl of the sink. Make use of a caulk gun to fix the caulk to the edges. Be sure that the caulk goes just in the direction of the sink lip and covers the entire length. But, you don’t need to exert a great deal of pressure to spread the caulk. Simply press gently on the gun. This should be enough.

Step 3

You must now reach beneath the hole in the kitchen sink to place the under mount sink. We advise you to seek assistance from a person. He should be able to hold the sink with a firm grip while you make sure you tighten the clips. It is evident that it is fitted with a lip for the sink under the sink- you must adhere to the hook in the mouth. You must uniformly apply the clips beneath the sink counter to ensure it is secured.

Step 4

Use a screwdriver to fix all the screws around the countertop and the sinkhole. Alternately, you can make use of a hand drill as well as the screwdriver bits. It is also possible to remove the caulk that is leftover in the event you spot something. You can do it by using a clean fabric and some water. Then, you should wait at least 24 hours to ensure it can be sure that silicone caulk has time to set into place. Then join the drain line as well as the faucet.

How to replace a broken under mount sink 

Step 1

Start the project by taking everything out of the cabinet. Then, shut off water valves that are located beneath the counter. Also, disconnect the sink’s P trap and drain. Unscrew the one side of the drain from the drain’s tailpiece by using the help of a screwdriver and then loosen the slip nut using two tongue and groove clamps. Carefully unscrew the waste trap arm’s opposite end and pour the excess water into the container.

After that, you’ll be able to remove the P-trap from the assembly and then place an apron that fits snugly inside an opening in the drainpipe. You can now utilize the pliers for disassembling the drainage tailpiece. Remove the mounting nut, tap the filter, and pull the drain assembly upwards and away from the sink.

Step 2 

Undermount sinks usually seal into counters using the sealant. However, larger sinks could also have clips to secure them. To take them off, it is possible to use the glue knife beneath the sink and press until the clips fall off. Examine the underside of the sink to find where the silicone or another adhesive joins the sink’s rim with the counter.

To proceed to the next stage, you’ll need to secure the sink securely, and it is possible to have a helper assist you with this. With the sink’s bottom being supported, begin cutting through the sealant. Continue cutting around the edges. Suppose your sealant contains a thicker substance, such as epoxy. In that case, you may have to employ the aid of a hammer and an ax to assist the rim breaking away with the counter.

Take then a grab a prybar and insert it to loosen the sink. The use of a heating gun or hair dryer may also help soften the substance if required. When the sink is removed and cleaned, remove any leftover sealant and take off the anchors that support it.

Step 3 

Before you purchase a new sink under mount, take careful measurements to ensure it can fit in the countertop’s holes. Make a few wooden pieces and place them on the counter for an interim sink stand. You can also drill a hole to accommodate a specific under-mount sink. However, consider each of these options before visiting the shop.

Utilizing the caulk gun, place a dense layer of caulk around all edges around the hole inside the counter. Raise the sink until pressed against the opening, creating an airtight seal. If you require sink clips, put them in place the clips according to the instructions. After this, Clean up any leftover caulk and allow the area to dry for a minimum of 24 hours.

How to install an under mount sink in quartz

Step 1

You’ll notice that there are already pre-drilled holes ready for mounting the countertop. You’ll need to secure the brackets that hold it in place. Then, apply silicone caulk to seal the flanges of your sink. It assists the sink stick on the counter. From underneath, connect the clips to ensure that the sink sits properly on the countertop. Finally, make sure the alignment is correct and clean any caulk residue using a clean cloth.

Step 2

From underneath, connect the clips to ensure that the sink sits properly on the countertop. Then verify the alignment and clean off any excess caulk using an e-wipe. You’ll need to install an under-mount sink on a Granite countertop in some cases. Many people believe that there is a difference between installing an under-mount sink in the quartz countertop and in the granite. We found them identical. Suppose you truly want to know how to connect an under mount sink onto granite countertops. In that case, it is possible to follow the Quartz installation process. The wooden installation is identical, so you should not have any issues with the Granite installation.


You can adapt under mount sink to the kitchen. Therefore, homeowners are on the lookout for it. Thankfully, installing the sink under mount in quartz, wood, or granite is quite simple. This DIY project on how to install and replace under mount sink is simple and doesn’t need any prior knowledge. Don’t let yourself get bogged down because of your lack of experience. Follow these steps to install and replace under mount sink and watch the magic happen.

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