Seal sinks for sturdy service

Seal your kitchen sink: An important task for the DIYer

Find out how to seal a kitchen sink or a bathroom sink to beautify and protect your home. Unsealed areas can collect moisture and dirt. It’s unsightly and can lead to big problems. 

Why you should seal around sinks

There are several reasons to make sure your sinks are properly sealed. A good seal will keep dirt and moisture from getting into the gaps around the sink edges and fixtures. Eventually, this could lead to mould, rot, and deterioration of the countertop around the sink.

The fixtures and the sink itself may be, at least in part, held in place with caulk. So replacing any missing sealant is important. And finally, a freshly sealed sink is much more attractive and easy to clean. 

How to seal a sink properly

Often you will need to remove the old caulk before applying new sealant. Use a utility knife or a caulk-removal tool to scrape away the caulk. Old silicone will often pull away in long strips once you get it started.

Make sure to clean away any residue or dirt before proceeding.

After preparing the area, follow these steps:

  1. Place the sealant in a caulk gun and cut the nozzle at the proper location for the desired size bead.
  2. Beginning at one corner, squeeze the trigger and run a smooth bead of sealant all the way across one side.
  3. Smooth out the bead with a caulking tool or with a moist finger. Make sure the sealant forms an even, watertight seal with no gaps.
  4. Continue with the other sides until the sink and any fixtures that come through the sink are sealed up.
  5. Allow the sealant to dry for the time specified on the label before use.
  6. Clean up your tools and any drips with a damp cloth.


Sealing an undermount kitchen sink is a bit different. These sinks are mounted with clamps from underneath the counter. If installing a new undermount sink, use pure silicone around the sink rim before clamping it into place. To reseal the sink, you may be able to loosen the clamps and apply sealant around the top of the sink. If loosening the clamps doesn’t give you enough room, the sink would have to be removed to reseal.

Is it best to use silicone around a sink?

One of the most common questions regarding this task is what type of sealant is best. Generally, silicone sealant around sinks makes the most sense. It is waterproof, durable, and adheres well. However, one drawback to silicone is that it is not paintable. If you will need to paint the sealant to match the surrounding areas, use a siliconized latex caulk. It has many of the same properties as silicone caulk but will take paint.

When selecting your sealant, look for one designed for kitchen and bathroom use. It will provide a waterproof finish and adhere to common materials found in these areas.

If you are resealing an old sink, we have some good news. You may be able to take care of the job in just minutes without the need to remove the old caulk. Loctite RE-NEW is the product that makes this possible. This unique mould-resistant formula is designed to adhere to and cover old, worn-out sealants. Just wipe them down with some household cleaner and you’re ready to go. The special applicator makes resealing your sink a breeze. No caulk gun is needed.