Installing an undermount sink to a quartz countertop is a great way to update your kitchen with a modern look. Unlike other sinks that attach to the top of the counter, undermount kitchen sinks attach directly to the underside of the countertop.
To install an undermount sink on quartz countertop, you first need to measure the dimensions of the sink and cut the quartz accordingly. Once you have cut the countertop, you simply need to attach it to the underside of the countertop using special screws (sink mounting clips) and washers.
If you want to create a space-saving, sleek and contemporary kitchen all rolled into one, installing the best undermount kitchen sink for quartz countertop can be the ultimate choice.
In this guide, I will guide on how to install an undermount sink on a quartz countertop.
How to Install an Undermount Sink On Quartz Countertop
Tools and materials needed:
- Hammer and nail set
- 1-inch screws
- Drill bit or hole saw
- Countersink bit
- Tape measure.
- Safety goggles and gloves.
- A clean cloth for cleaning up
Step 1: Making a Plan for the Installation
As with any sink installation, you’ll need to plan out your installation. You’ll need to make sure that you have enough space in your wall (or at least under your counter) for all of your pipes and valves.
Make sure they don’t interfere with any other sinks or cabinets for everything to fit correctly.
Plan it all out beforehand—you don’t want to be dealing with significant changes down the line when you plan everything.
Step 2: Mark your cutout
Before cutting out the countertop for installing the sink, mark precisely where you want your faucet and soap dispenser to go.
Take into account that most sinks require about 1/4 clearance around all sides of your faucet—but double-check for any special instructions.
Mark both on your countertop and on your sink base, as it’s often easier to line them up from underneath.
If you’re working with white quartz, you need to ensure that any marks won’t show up when looking at it from above. Add extra space in front of those markings, so the edges of your counter cover them.
Step 3: Drill two holes on the cutout mark
Drill about 1/4 inch from each side of your cutout mark. Be sure not to drill through your cabinet bottom. You want to leave enough wood intact to have some support for your faucet base plate.
Also, note how far apart you’ll need holes drilled on either side of each sink. It ensures they fit properly against each other once installed on your sink’s base plate.
Repeat as necessary, depending upon how many single and double basins you plan to install on your countertop.
Note: The hole should be slightly smaller than your faucet shank. If it’s too large or doesn’t line up correctly when installed, take out those bolts and try again.
Step 4: Apply lubricant around the sink’s base
The need for under-mount sinks necessitates using water-based lubricant so that you don’t scratch the quartz.
The best way is by using a spritz bottle. A small amount around all sides should be enough. Lubricating your sink’s base means you’ll have less drag when installing it and won’t risk scratching your countertop.
Make sure you keep any excess lubricant away from the sink edge or bottom lip of your counter. Otherwise, it can get inside over time and damage whatever lies beneath.
Step 5: Insert two plastic anchors into each of the two holes
Align each plastic anchor over each hole, and tap it down gently with a hammer, so you don’t crack your quartz counter. The goal is to have about 1/8-inch of a plastic anchor extending from the surface of your quartz countertops.
The plastic anchors ensure that your sink is securely attached and won’t get loose over time.
Step 6: Press down until you hear a click sound from each anchor
This step is very important. The anchor should make a click sound once it’s in its final position, and you should feel it on your fingertip as well. The sound and feel are your assurance that you’ve pressed down hard.
And when we say firmly, we mean it! The anchors will pop up again when you tighten down on the screws if you don’t. In other words, each anchor must be seated under at least 1/4 inch of quartz before moving on.
Step 7: Attach sink clips
For the undermount sink to sit on the quartz countertop properly, you’ll need to attach clips onto your sink’s baseplate. The purpose of these clips is to grab onto your quartz countertop.
Place the sink over the top of your quartz counter, lining up with its holes so that it covers the counter evenly.
Put your hands on each side of your counter and press down firmly (this helps you know where exactly you want each clip).
Use pencil marks or something similar as guidelines; then remove them and put one clip in at a time until all four are attached (two on each side). Attach screws into each clip and tighten securely.
Step 8: Attaching drain pipes to the bottom of the sink
Your sink will likely come with a metal ring already attached to it. It serves as an overflow pipe and a mounting spot for your garbage disposal.
Step 9: Attaching the sink to the countertop
Using a rubber mallet or hammer, tap gently on the backside of the sink basin until it fits snugly into the countertop cutout area.
If your sink does not have mounting hardware, use silicone adhesive to hold it in place.
How to Make Support for an Undermount Sink
- 3/4 plywood
- 1/4 hardboard or Masonite
- Nails or screws
- Table saw
- Mitre box
1. Measure & cut out wood
The first step is to measure and cut out your piece of wood to be 15 long, 5-1/2 wide, and 1-3/4 thick. It will serve as your under-mount sink support base.
With some minor adjustments, you can always make it fit later on. I like using 1/2′′ or 3/4′′ plywood, but any light, sturdy wood should work just fine.
2. Cut out the opening for the drain pipe
After you’ve determined where you want your drain pipe to go, measure out 1 inch from each side of your opening and make two marks on either side.
Use these marks as reference points while you cut out your pipe. Cut out a rectangle around it.
Ensure that whatever shape you leave behind will be wide enough. So that when you slip in your drain pipe, it has some room left over to work with and not be too constricted.
3. Attach plumbing
The plumbing is what gives you water and waste lines in your kitchen. These must be installed first before any tile work.
Plumbing requires basic tools, like a pipe wrench and PVC solvent cement. If you’re not sure where things go or don’t have time to mess with pipes, call in professional help.
4. Attach legs
With bottom support secure, it’s time to attach legs. Be sure the legs are level and at a proper distance from the base plate (You can place scrap wood on the legs).
Then attach the legs to the bottom plate with screws. Remember to leave plenty of room between the sink’s center and wall, as you will need access to the side for drainpipe installation.
5. Secure legs into place
All four legs should be screwed into place and secured tightly. If your sink is large or heavy, you may want to secure it in position with clamps until all of your screws are tight.
Finally, make sure that your legs are level and that they do not protrude into your kitchen space. Once everything is level and plumbed correctly, tighten each leg with a screwdriver until it does not move.
How to Install an Undermount Sink on Quartz Countertop without Clips
You have to be careful how you go about it to ensure your sink properly and safely stays in place. The most effective method involves using a suitable adhesive for undermount sink to ensure excellent support for your sink.
Step 1: Preparation
First and foremost, you must ensure that both your countertop and sink surfaces are clean, clear of any oils or residue, and free of debris.
You want a solid connection for both your tape measure and level, as well as for installing the sink on a quartz countertop. To clean these surfaces, wash them with soap and water, followed by a grease remover or cleanser.
Silicone is fantastic for sticking things together because it has shear, which holds items together under pressure and movement. It also helps create a watertight seal, preventing leaks and other problems down the road.
Step 3: Installation
The first step is to apply adhesive under its lip and position it. It’s best to center your sink on where you’ll want it since moving it after installation can damage both surfaces if not done properly.
Make sure you leave at least an inch of space between the bottom of your sink and whatever surface lies beneath (such as a countertop).
If there are any pipes within 10 inches of where you’re planning on installing your new sink, they should be removed or rerouted before proceeding.
Step 4: Cleaning
Clean immediately after installation. You’ll need to get extra silicone off your sink edges as quickly as possible.
To prevent dirt from getting stuck in any dried silicone still attached to your sink edges, use a razor blade or putty knife for cleaning. Silicone dries very quickly, so you only have a few minutes.
Installing an undermount sink to a quartz countertop shouldn’t be a daunting task, but following each step outlined in this blog will ensure that your kitchen stays looking beautiful for years to come.
If you have any questions or encounter any problems while installing your undermount sink to quartz, don’t hesitate to let me know in the comments below.
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