DIY French Door Astragal

French doors don't always meet securely in the center, allowing drafts into your home.
French doors with an astragal can block light, sound and air.French doors with an astragal can block light, sound and air.
In driving rain, poorly fitting French doors may even let water in. When you are ready to close the gap in your French doors, install an astragal, which is an insulated molding piece that fits onto one of the doors and covers any space between them. They are designed to look as if they are a part of the door and will not detract from the look of your French doors.

Step 1

Select the door that will have the astragal mounted on it. Choose the inactive door, which can be the door that either does not open at all or is not the door that is primarily used. Identify which side of the door the main piece of the astragal will appear on -- it should be on the side of the French doors where the primary door swings away from you to open it.

Step 2

Measure the height of the inside of the inactive door, the space between the two doors when closed and the thickness of the door end. Purchase an astragal kit to these specifications, as astragal strips can be customized to fit many door heights and thicknesses. An improperly fitting astragal may interfere with how the doors open and close and may not seal the crack in between them.

Step 3

Open the doors so you have complete access to the inactive door. Check that the molding part of the astragal is on the proper side of the door. Hold the astragal strip against the door end and press. The astragal strip will flex open and clamp onto the end of the door. Press all the way down the strip until it is completely on.

Step 4

Locate the screw holes and drive the kit screws into the door. Screw them in until the tops are flush with the astragal strip to avoid interference with opening and closing the doors.

Step 5

Slide the plastic insert strip into the channels of the astragal to cover up the screws and provide a clean-looking finish. Test the doors a few times to ensure a good fit and to verify that there are no gaps between the doors.

Things You Will Need

  • Measuring tape
  • Astragal kit that includes screws
  • Drill


  • If your doors are made of metal, you'll need to use a metal drill bit of high-speed carbine to make pilot holes for the screws before inserting them.
  • Astragals come in many different colors, so order one to match your French doors. If you cannot find a match, sometimes a complementary color works, and you can paint the door trim to the astragal color.

About the Author

Jenna Marie has been editing and writing professionally since 1993. Her editing background includes newspapers, magazines and books, and her articles have appeared in print and on websites such as Life123 and AccessNurses. She specializes in writing about parenting, frugal living, real estate, travel and food. Her nonfiction book was published in 2008. She earned a Bachelor of Science in journalism from Utah State University.