How to Seal Air Leaks with Caulk

How to Seal Air Leaks with Caulk

Regardless of the season, air leaks can cost you hundreds of dollars in wasted energy each year. When air is leaking from your home, it forces your heating and cooling systems to work harder to regulate the temperature, which ultimately raises your energy bill. Filling air leaks with caulk is a quick and easy way to prevent waste. The steps you can take to get started are outlined below:


  1. Click here to learn how to detect air leaks in your home.
  2. Is caulk the right material for your air leak? Caulk is a flexible material used to seal air leaks through cracks, gaps, or joints less than 1-quarter-inch wide between stationary building components and materials. For components that move – doors and operable windows, for example – weather stripping is the appropriatematerial.


  • Caulk for sealing windows and doors (latex or silicone-based)
  • Caulk gun
  • Putty knife or large screwdriver (for removing any old caulk)
  • Paper towels or a rag for cleanup
  • Flashing material for larger openings (e.g., thin board sheathing, sheet aluminum, etc.)


  1. Clean the area that is about to be caulked: Wipe the area down and ensure that there is no old paint or caulk in the space.
  2. Prepare your caulking gun: At the tip of the caulk cartridge, cut a tip that slants at a 45 degree angle. Then, insert the tube into the gun. Practice using the caulking gun by slowly pulling the trigger over the newspaper – this will also ensure that it is working properly.
  3. Hold the gun at a 45 degree angle against the edge that is going to be filled: Begin gently pulling the trigger and pull the gun slowly across the joint. Avoid stopping and starting – try to pull in one continuous motion.
  4. Push the caulk in: Using a spoon or a wet finger, press along the surface of the bead of caulk and push it into the crack to make sure the gap is sealed.
  5. Clean up excess caulk: Keep a damp rag nearby to clean up any excess caulk.
  6. Give the caulk time to dry: Reference the tube you are using for directions on letting the caulk dry. Typical recommendations are to let it sit undisturbed for 24 hours.

SOURCE: The U.S. Department of Energy