How To Fix Gap Between Sink And Counter with Caulking

It’s troublesome to call a plumber over a simple job. To fix the gap between sink and counter is an easy task. If the gap between the sink and counter is open, then water can enter, creating mold.

You need to be careful while filling gaps in the undermount and flush mount sink. I know you are not a professional plumber, neither am I. But I have been doing all the plumbing work in my home by myself for years. I know very well how to describe easy steps for you to follow.

In this article, we will try to explain it for both sink types most easily for you. Read the article from top to end for a better understatement.

How To Fix Gap Between Sink And Countertop

Undermount sinks need to have a cutout with a countertop. While installation of the undermount sink, a small gap between sink and countertop might remain. It’s best to use good silicone caulk because they secure everything tightly. However, silicones are quite tricky to remove for reinstallation.

Here are 4 easy steps on how to fix gap between undermount sink and countertop gave below:

  1. Take a caulk tube nozzle, then cut it using a knife according to the size of the gap between the sink and countertop. Mostly, the size is about ½ inch.
  2. Then make sure that the caulk tube is faced towards you while inserting it. If it’s not facing you, the caulk may begin to form a pile on the top of the tube. It will be messy and unfixable.
  3. After placing the caulk tube, you need to make it smooth. Just use your fingers to smooth out and dry rag to hold while doing the work.
  4. At last, fixing the gap of the undermount sink to granite will be finished.

4 Steps To Caulk Flush-Mount Sink

Flush-mount sinks are very stylish, but the problem is it has to be caulked very carefully. If the caulk is visible, it will destroy the beautiful look of the sink and countertop.

So, the gaps are filled in such a delicate way that silicone sealing should not be seen from above. The process of undermount and flush-mount is quite similar. Such as:

  1. Use your finger or a plastic knife to make a smooth-out caulk if a new caulk has a bit of a gap on your flush-mount sink.
  2. The transition of the silicone caulk will be on the same plane. However, It’s not possible to match the caulk completely with the sink.
  3. Just use the under mount sink technique to fill the gap. Cut a nozzle of the tube and insert it into the gap.
  4. Lastly, the gap would be sealed tightly, but from above, the gap would be visible. Don’t worry. Water won’t enter it.

Essential Tips To Fix Gap Between Sink And Countertop

These tips are some observations that I made by making mistakes. These would help you not to repeat them. Such as:

  • Don’t use a wet rag while inserting the silicone caulk. Because even though silicone caulk is waterproof, the wet rag can create mold in the gap.
  • Make sure that the caulk is fixed tightly. Otherwise, your caulk can open up automatically.
  • If there is water formed inside the gap, try to soak up the water using a thin sponge.
  • Don’t use a sharp knife for filling the gaps.
  • It’s best to smooth the caulk using your fingers because, in this way, you can make sure there is no space or gap left.

This Video Will Help You Too!

Frequently Asked Questions (FAQs)

How do you fix a gap between the drop-in sink and countertop?

You can fix a gap between the drop-in sink and countertop using silicone caulk. If there is an old silicone caulk, then first remove the caulk properly, then reinstall a new one. Drop-in sinks are known as overmount sinks. They are pretty outdated now in comparison to under-mount sinks.

Should there be a gap between the sink and countertop?

No, there shouldn’t be a gap between the sink and countertop if everything is placed rightly and your sink is perfectly sized.

What should I put between the countertop and sink?

You should put a silicone caulk between the countertop and sink. It’s the best option because it is waterproof. Nowadays, everyone uses it because it prevents water from entering and stops molding issues. Don’t wait too long, and fill up the gaps correctly with silicone caulk. Silicone caulk is flexible, so it is not too hard to use.

Is caulk the same as filler?

Yes, caulk can be used the same as filler. However, It’s best to fill up the gaps between the door frame, sink and countertop, edges between any shelves and wall using a caulk. If it is not used properly, caulk can start getting out.

How big a gap can you caulk?

It’s possible to caulk a big gap of ¼ inch at a time. Because one single tube of caulk is ¼ inch wide, you can cut and make it small according to the gap between your countertop and sink. For bigger gaps of more than ¼, you can use more than one bead of caulk by cutting and resizing them according to your required fitting.


In a nutshell, before starting, we want to suggest that you should see the gap between your sink and countertop for buying perfect silicone beads even though you don’t have any experience on how to fix gap between sink and counter you can do it.

These steps and important tips will help you to fix the gap properly. You can follow our other articles for more easy-peasy guides on DIY plumbing.

You Can Also Read:

Similar Posts