Lowe's Home Improvement

How To Caulk

You've selected your project and purchased the caulk and accessories. Now it's time to learn how to caulk. These easy steps will give you the smoothest and cleanest results possible.

Man using a caulk gun

Tools & Materials

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Why Caulk?

Package of Caulk

Caulking fills gaps and cracks to keep air, water and bugs out of your home. Caulking is typically done around windows, doors, pipes, plumbing and wherever there's a break in siding. If you're unsure of the type of caulk to use, check out our Caulk Buying Guide to buy the right type for your project.

Preparing to Caulk




Step 1

Remove old caulk using a caulk-removal tool or utility knife. Dislodge and remove all old caulk in the joint.

Step 2

A clean surface is key to ensuring a sealant will bond. Make sure that the surface is clear of old caulk, peeling paint, dirt, rust, mold or moisture. Use a wire brush and a caulk-removing solution to clean the surface. Then, for indoor projects, wipe down with rubbing alcohol or disinfectant.

Step 3

Add touch-up paint to any areas that are weathered or were damaged when the caulk was removed.

Step 4

If your project is indoors, apply painter's tape around the area you're caulking. This will result in cleaner caulk lines.

Loading a Caulk Gun



Step 1

Caulk gun

Press the release at the rear of the gun with your thumb, releasing the plunger at the back of the gun. Pull the plunger all the way back. Put the tube into the gun, with the nozzle in the front. Push the plunger tightly into the back of the tube, and remove your thumb. The gun is now loaded.

Step 2

Cut the tip of the cartridge so that the hole matches the size of the gap you want to fill. For smaller bead size, cut closer to the tip of the nozzle. For larger bead size, cut farther from the tip of the nozzle. Repeatedly push a nail or awl through the hole to puncture the inner seal.

Apply Caulk

Watch Our Video: How Do I Use Caulk?


Step 1

Test the bead size on newspaper or a paper towel to ensure it's the appropriate size.

Step 2

When applying the caulk, it's better to pull the caulk gun along the joint. Pushing can result in an uneven bead. Hold the tube at a 45-degree angle to the joint being filled. Apply steady pressure to the trigger of the caulk gun.

To stop the flow of caulk, release the trigger and pull back the rod behind the cartridge.

Good to Know

Keep in mind some caulk that will dry clear will look white or milky while you're applying it.

Step 3

Tool newly applied caulk. Tooling is passing over the entire applied bead of caulk to smooth it and push caulk into the gap between your substrates. Use a caulk finishing tool to pass over the entire bead. If you don't have a finishing tool, you can use a paint stirrer, a spoon, a foam paintbrush or a glove-covered finger dipped in rubbing alcohol or water.

Step 4

Tooling and tape removal should be done before the caulk begins to dry/cure and skin over. For best results, remove tape by carefully pulling it away from you at a 45-degree angle.

Clean Up

It's important to immediately clean up any caulk. Keep rags handy for wiping up any mistakes.

Many uncured latex-based caulks can be cleaned up with water. Silicone caulk should be cleaned up with mineral spirits or rubbing alcohol. Dried caulk will need to be cut or scraped away.

Check the manufacturer's cleanup instructions for details.

Capping off Partially Used Caulk

Caulk tube stoppers are the best way to ensure your caulk does not dry out between uses. If you don't have a stopper, place a nail at least 2 inches in the nozzle of the caulk tube. Then wrap the nozzle tightly in plastic wrap or foil.

Check manufacturer’s recommendations for storage.

Good to Know

Check to make sure the caulk that's been in your garage is still good. First, find the "Use By" date. If a date can't be found, apply a line of caulk down a piece of cardboard and wait 15 minutes. If the product doesn't form a skin, it needs to be discarded.

Reopening a Used Tube

If you're reusing a tube of caulk, cut the nozzle using a utility knife slightly larger (closer to the base of the nozzle) than the previous cut. Then, drive a screw into the nozzle through the hardened caulk, leaving enough room to grab the end. Use the screw to pull the hardened caulk out of the nozzle.