How to Use a Caulk Gun

Learn how to seal gaps, cracks, and crevices with a smooth bead of caulk.

Caulk is a commonly used product in many home renovation projects. When applied in a smooth bead, it forms a watertight seal in narrow gaps and crevices. In a kitchen or a bathroom, caulk seals moisture in to prevent it from seeping into walls, behind cabinets, or even behind tub or shower tiles.

Used around windows and door frames, caulk can keep out insects, seal out moisture, and reduce the flow of heat through the exterior wall of the home, allowing you to save on heating and cooling bills. However, if not applied properly, caulk can form an incomplete seal along the length of the crack or crevice, limiting the protection it provides to your home.

In order to ensure that you're applying caulk correctly, it's important to learn how to use a caulking gun. This simple tool makes it easy to run a bead of caulk around a window, along the top of a bath, or even between a bathroom vanity and wall to help control moisture. Use this guide to learn more about caulk and how to use a caulking gun.

Types of Caulk and Caulking Guns

Before starting any project, it's a good idea to look into the tools and products involved. You can opt for a battery-powered caulking gun, though the cost of these tools far outweighs the inexpensive price of a manual caulking gun. Unless you plan to frequently use a caulking gun, a manual caulking gun is typically sufficient for DIY projects.

Similarly, when working with a caulking gun, you need to consider the type of caulk, based primarily on the location of your project. For instance, if you are applying the caulk in a kitchen or bathroom, silicone caulk is the best option because it acts as a sealant, repelling moisture, mold, and mildew.

If applying caulk around baseboards or trim, you can use latex caulk to get the job done. Latex caulk expands to fill crevices better than silicone caulk, However, latex is vulnerable to damage from repeated exposure to water and direct sunlight, so it isn't the right choice for high-moisture areas or locations that get a lot of sun.

adding caulk paste in gap between wood panel wall and ceiling
Marty Baldwin

How to Use a Caulk Gun

Learning how to use a caulking gun is relatively straightforward and does not require many tools to complete. Follow the steps below to learn how to use a caulk gun for your home renovation projects.

What You Need

  • Putty knife
  • Cloth or rag
  • Soap
  • Painters tape
  • Caulk
  • Caulking gun
  • Utility knife
  • Long nail (optional)

Step 1: Clean and Tape the Area

Inspect the area where you will be working. If there is an old bead of caulk or bits of old caulk remaining, use a putty knife, utility knife, or caulk removal tool to scrape away any residual caulk. When the gap or crevice is clear of the old caulk, use a rag with hot soapy water to thoroughly clean the area.

After cleaning, give the surface time to dry, then apply strips of painters tape on either side of the crack or crevice to protect the surrounding area. This can also help keep your bead of caulk straight when you apply it with the caulking gun.

Step 2: Cut the Tube Tip

The tip of the caulk tube will determine the thickness of the bead, so before cutting it, take a few minutes to consider how thick you need the bead to fill the gap or crevice. If you want a narrow bead of caulk, cut a 45-degree angle near the top of the tube tip with a utility knife or scissors. If you want a thicker bead of caulk, cut a 45-degree angle slightly lower down the tube tip.

Inside the caulk tube tip is a seal that needs to be punctured to release the caulk. You can use a long nail to pierce this seal or you may have a caulking gun with a piercing rod that is specifically intended for this purpose. Similarly, some caulking guns have tube tip cutters built into the body, so you won't need to worry about having scissors or a utility knife on hand.

Step 3: Load the Caulking Gun

Load the caulking gun by pressing the release trigger located on the handle. With the release trigger depressed, pull the metal rod all the way back, then slide the tube of caulk into the cylindrical holder. You will need to insert the flat base of the caulk tube into the back of the holder before slipping the tip of the tube into the front of the gun.

Once the caulk tube is in place, gently push the metal rod back into positioning, taking care not to force the metal rod through the back of the tube. If done correctly, the metal rod will stick out several inches from the back of the caulking gun and the caulk tube will be held firmly in place.

Step 4: Apply Caulk in a Straight Bead

To get a feel for the speed at which the caulk will be released, aim the caulking gun at a scrap piece of wood or paper, then squeeze the trigger. This will move the metal rod forward so that it pushes the plunger inside the tube and forces the caulk out of the tip of the tube. Run a short bead of caulk along the scrap material to test the thickness of the bead and the flow of the caulk.

When you are ready, line up the caulking gun with the gap or crevice and squeeze the trigger of the caulking gun to apply the caulk. Start in one corner and run a single continuous bead to the center, then start in the opposite corner and run a second continuous bead until it meets up with the first in the center.

If you find that caulk stops coming out of the gun, it may be because you have squeezed the trigger as far as it will go. Simply release the trigger, allowing it to return to its normal position, then squeeze the trigger again to resume the flow of caulk. Try to keep your movement along the line as steady and consistent as possible.

Step 5: Smooth the Bead of Caulk

After applying the bead of caulk, finish the job with a process known as tooling. Tooling is simply the process of smoothing the bead of caulk into the gap or crevice. You can use a caulk smoothing tool or your finger to smooth the bead of the caulk by applying light pressure to the caulk as you run your finger along the length of the bead.

When you are satisfied with the results, remove the painters tape and leave the caulk to dry for as long as the manufacturer recommends. Typically, caulk will dry to the touch in a few hours, but it can take up to 48 hours for it to properly cure. Curing is especially important for high-moisture locations, like the kitchen or bathroom, so be sure to read and follow the label.

How to Remove Old Caulk

Caulk can last for many years without a problem, but over time it will gradually begin to break down, so it's recommended to remove old caulk and replace it with a new bead of caulk about once every five years. Some people may try to simply apply new caulk over existing caulk, but this rarely works. Instead, the new bead of caulk is unable to form a proper seal with the old caulk or the surrounding edges, leading to mold and mildew growth, water damage, and rot as water seeps through the ineffective seal.

Removing caulk isn't a difficult task, but it is necessary. In most cases, you can scrape the old caulk off the edges of the tile, baseboard, trim, wall, or any other surface to which it adheres. Simply use a utility knife or putty knife to separate the old caulk from where it is currently installed.

If you are having trouble, consider using a caulk softening solution, a caulk removal tool, or even a set of needle-nose pliers to grip the beads of caulk and slowly pry it out of the gap. Once the old caulk is removed, scrape away any remaining bits with your putty knife, clean the area, and allow it to dry, then apply a new bead of caulk to seal the crack or crevice.

Was this page helpful?
Related Articles