How To: Use a Caulk Gun

Let us show you how a simple, affordable caulking job can help you keep unwanted invaders like mice and mildew as far away from your home’s cracks as possible.

By Rachelle Dragani and Bob Vila | Updated Oct 22, 2020 9:50 AM

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How to Use a Caulk Gun


Caulking is one of the easiest and most affordable home fixes. By sealing off unwanted cracks in places like windows and bathtubs with a bead of waterproof filler, you’ll be able to prevent home invasions like mold, leaks, and bugs. Plus, it can prevent less air from passing through the cracks around unsealed windows and doors and ultimately cut down on energy costs. All the process requires is good aim and patience. Though some home repair novices might be intimidated by the contraption, it’s actually a simple tool to use—we’ll show you how with this guide on how to use a caulk gun.

Before getting started, make sure you pick up the right tools. The specific type of caulk you get will depend on the type of job you’re doing. For an indoor job someplace exposed to a lot of water, like a bathtub, you’ll want a silicone caulk that acts as a sealant and also repels moisture—a great defense against mildew and mold. For work that won’t see as much water or sunlight, like the baseboards around the basement floor, a latex caulk might better suit your needs. Latex varieties expand to fill crevices a little better than silicone varieties, but repeated exposure to rain, sunlight, or water will have it breaking down much earlier than the latter variety. Your local hardware store can help you determine what’s best for you.

Give equal attention to deciding upon the right caulking gun. The expensive battery-powered ones are nice, but homeowners can get professional results with a simple, affordable ratchet rod caulk gun. This isn’t the place to save money on home repairs, though. Caulk guns aren’t expensive, but the super cheap ones can be flimsy or break halfway through a job. Spend the small amount of extra money on a reliable and sturdy model.

How to Use a Caulk Gun


Step 1

Get rid of all the old caulk, paint, mold, or rust around the area you’re going to caulk. You can use tools like a putty knife or wire brush to clear the existing gunk. A small vacuum can also be useful for sucking up hard-to-reach debris. Then, thoroughly wipe it down with vinegar, liquid caulk remover, or bleach. Once clean, you must let the area completely dry. This is an essential step: If you lock in any moisture with your caulking job, it could lead to mold.

Step 2

Prepare the area for caulking. If this is an indoors job, like a shower, apply painters tape to the area. Take the time to smoothly apply a piece of tape both above and below the line you want to caulk, giving yourself about one-eighth of an inch of space on either side of the crack. It will make your caulk lines cleaner and more aesthetically pleasing.

Step 3

Cut open your tube of caulk with scissors. The size of the opening will depend on the task at hand. For precision jobs like bathtub tiles, you’ll want a fine opening made by cutting the tube at a 45-degree angle near the top of the pointy nozzle. For rougher jobs such as applying adhesive, you can make a bigger, straight cut at the middle or bottom of the nozzle.

Then, use something sharp like a nail or pin to poke through the opening and the internal seal.

Step 4

To load a caulk gun, press the release trigger located on its handle and then pull the metal rod all the way back. Every gun is a little different, but assume that the hook at the back of the ratchet gun must be facing down at a 90-degree angle when you pull this back. With the rod back, insert the fresh tube of caulk. Place the flat base of the caulk tube in the back of the gun, and then allow the nozzle to rest in its place at the front of the gun. Then, gently push the metal rod back into place as far as it will go.

Step 5

Do a caulk test on a piece of paper before you begin. Hold the gun at a 45-degree angle and gently squeeze the trigger to form a line of caulk. You’ll have to continue tapping the trigger lightly as you dispense a bead of caulk. Press the trigger and move at a medium, steady pace—too slow and the caulk will get clumpy, too fast and it will become thin and uneven. If you find that you’ve pulled the trigger all the way back and caulk stops coming out of the gun, that’s okay: Gently let it go and start anew, trying not to let too much caulk pool up at the exact spot where you’ve started over.

Once you have a feel for the flow, carefully apply the caulk to your surface. Try to keep your movement along the line as steady and consistent as possible.

Step 6

As soon as you’ve finished caulking, smooth over the caulk with a finishing tool, an ice cube, or a gloved finger or spoon dipped in a bit of water. This light pressure applied by a slick tool will give you the even, smooth lines of a professional job.

Step 7

Clean up right away. Peel off the tape in a big, sweeping motion, and let the bead of caulk dry unbothered. The caulk tube should inform specifically how long that will take, but most are dry within 24 hours.