How To Install Undermount Bathroom Sink To Granite

How To Install Undermount Bathroom Sink To Granite?

If you want your bathroom to look elegant and sleek, there is no addition that can have a greater effect than the appearance of your sink.

It is the most defining fixture in the bathroom. For a cleaner look, get an undermount sink to go with the rest of the bathroom decor.

Contrary to popular belief, installing an undermount sink to granite is really not that tough of a job. As a matter of fact, to the plumber, this installation is only as much of a hassle as that of the top mount sink’s.

To delve deeper into the matter, read through this article, and you will learn how to install undermount bathroom sink to granite.

What You Will Need?

Be well prepared by having all the items you need at hand. Down below, you will find a list of items that you need by your side before you get down to business.


While picking out from the numerous options in the store, keep your granite counter in mind. Do not opt for something that just looks good by itself. Remember to match the design and texture of the undermount bathroom sink with that of the counter where you will set it in.

You need to be careful if you get a composite sink because those might stand in stark contrast against your counter, and make the whole set up look grotty. Hereon, you can go to a physical store or look online to find sinks that are on sale, in order to cut down on the cost.

Here are the tools required to finish the installation process;

  • Power drill
  • Drill bit
  • Wing nuts
  • Screwdriver
  • Silicone Sealant
  • Clamps
  • 2 x 4 Lumber
  • Pencil

If your sink doesn’t come with a mounting hardware, then you should get them separately too.

How To Install Undermount Bathroom Sink To Granite

How to Install Undermount Bathroom Sink to Granite?

Begin the installation process on a free day, because it will take you a lot of time to get it all done carefully and precisely.

Step 1

There should be some holes drilled into the graphite. You can do this on your own by using a power drill machine. You will need to get a drilling attachment tool of the perfect size for the screws to go in.

Otherwise, it will be of no use to you. If you have never done this before, we would strongly suggest you to get someone to do this part for you.

Get professional help because it might be a little unnerving to work with a power drill if you have no experience on it.Getting a mechanic to drill some holes will not cost you a lot of money, so you might as well just get help and ensure your confidence for the entire task doesn’t plummet.

Step 2

Measure the length of the hole in your counter. You will now need to cut your 2 x 4. The 2 x 4 must be cut exactly 1 foot longer than the hole in the counter.

Put the 2 x4 over the hole, align it according to the width, so that the 2 x 4 sits on the hole with 4 – 6 inches of it resting on each side of the graphite countertop.

Make sure it stays stable over the hole. This 2 x 4 will be used as the points of contact for you to measure the placement of the sink as it is pulled up with clamps, as stated in the following step.

Step 3

In this step, you have to get all the measurements right. It’s just about scaling and getting the right layout for the clamps. Begin by using the drain holes of the sink and the 2 x 4 as your reference points. Pull up the sink to the underside of the counter with your bar clamp.

Then clamp it up with care. Do not tighten the clamps too much if you don’t want to damage the surface of the granite. It should have a snug fit into the hole. To ensure that you have done the job correctly, try moving the 2 x 4 lumber.

It should shift to the tiniest degree along the counter, but no more than that.

Step 4

Once you have the layout and the measurements ready, fasten the wing nuts into the screws that are to hold the sink. Then check if the nuts are in alignment with the layout. If everything is alright, move on to the next step.

Otherwise, you have to open the nuts and screw them back in again. Once the alignment is done, mark the spots of the wing nuts. Then un-clamp the sink and put it away for the time being.

Step 5

Look at the pencil marks, take a 1/4 inch drill bit, and drill holes through the pencil marks. Be very cautious in this step, because the graphite might get scratched off if you don’t watch it. Once the holes have been drilled into place, clean the area.

Use rubbing alcohol to clean the ridge completely.

Step 6

Now put a beam of the silicone sealant around the ridges. Make sure the lines are clear and straight. Now quickly bring the bathroom sink up and put it on the beam. Then using the bar clamp, clamp it up in the right spot so that there is a secure hold on it.

Thread the wing nuts into the drilled holes, tighten all the screws, and you are done. Finally, rub off the residual sealant from around the ridge before it dries up. And there you have it – a perfectly secure and solid set up in your bathroom.

Now, all you have to do is wait for the sealant to dry up completely. This will take up an entire night. Check in the morning for any leak that might have accidentally been looked over. If everything seems to be in the right tight spot, then you can go on ahead and fasten the plumbing fixtures.

Frequently Asked Questions (FAQs)

Which is the best adhesive for undermount sinks?

There several types of adhesives that which you can use to hold together an undermount sink. However, not all have the same quality to serve the purpose. The following product, therefore, can work well when installing one:

The silicone silk caulk.

The product is specifically for undermount sink installation. It has water-repellent characteristics, and it bonds well to both ceramic and countertop laminate. The glue is the most used for this purpose worldwide!

How to attach an undermount bathroom sink to granite?

All that you need is silicone adhesive. To start the process, you will have to apply a thin line of the silicone around the sink underside of the granite.

Place the sink over the space to install, and its weight will slightly compress the adhesive, and hence making it to spread out. The thin line of the adhesive is what you need most!

Do you require clips for the undermount sinks?

It depends on how you do the installation. You may either use the brackets or the clips. If you prefer to go for the bracket option, then the use of clips will not be necessary. You can always use them interchangeably!


The undermount bathroom sink installation is not at all a difficult process. But it is a process that will require you to be very careful and focused on all the steps. One slightly wrong angle might cause you to do the whole thing again.

So before you try this, make sure you are confident about it. Follow all the steps carefully, and keep your cool. You’ll be able to finish it in a breeze.

Take your time and take it slow. Best of luck!

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