How To Seal The Gap Between Double Doors

A gap between double doors can cause drafts, debris, and pest infestations. Well, if you're looking to seal the gap between your double doors, you've come to the right place. We've researched the steps to do it as well as the best materials to use. In this post, we'll discuss how to get it done.

Here are the steps to seal the gap between your double doors:

  1. Inspect the doors and make sure that they're correctly aligned
  2. Measure the width of the gap
  3. Prepare the doors
  4. Cut the weatherstripping
  5. Look for open spaces and seal them

Sometimes gaps between double doors are caused by doors that have been installed incorrectly. And other times, the weather seal between the door can bend, rip off, or wear out over time, leaving an open space. The amount of space and the location of the doors will determine the best way to close this gap. Continue reading to learn more about the options available.

Bedroom with French Door Balcony, How To Seal The Gap Between Double Doors

Steps To Seal The Gap Between Double Doors

The light shines on the white door

You can use silicone weather stripping, door sweeps, or a combination of the two to seal the area between your double doors. The silicone creates a soft and durable seal, while the door sweep acts as an extra barrier to prevent cold drafts from entering through them.

Things you'll need:

  • Weatherstripping
  • A cleaning cloth
  • Shears
  • Door sweep
  • Measuring tape
  • Electric drill
  • Screwdriver

1. Inspect the doors and make sure that they're properly aligned

Take a look at the doors and the gap to ensure that they are properly aligned with one another as well as the door frame. If the doors aren't aligned properly, this can create issues when trying to close the gap. Keep in mind that over time, doors can start to sag on the hinges, which can cause gaps and crevices between them.

Sometimes simply tightening the fasteners or screws within the hinges can help hold the doors back together. However, in drastic cases or those caused by improper installation, this may not be possible. In this case, you may simply need to remove the doors completely, re-measure them, and reinstall them so they're aligned properly.

2. Measure the width of the gap

Take a look at the gap between the doors and measure it with your measuring tape. The thickness of the gap will help you determine if weatherstripping alone will close the gap or if adding a door sweep in addition to the strips will be beneficial.

Find weatherstripping on Amazon.

3. Prepare the doors

If there is any old or torn weather stripping in its place, be sure to remove it before applying the new strips. Next, remove any former adhesive or grime using adhesive remover and clean the door frame using an all-purpose cleaner.

4. Cut the weatherstripping

Weatherstrip tape. Self adhesive foam window seal strip for doors and windows.

Next, measure and cut the weatherstripping to the length of the doors. If the stripping is much thicker than the gap, be sure to cut it to size so that it is not overlapping the doors too much. Remove the adhesive backing from the stripping and apply it to the doors.

Be sure to press the strips in place firmly. Be sure to run your fingers up and down the length of the strips to ensure that they're free of air bubbles and have a tight seal.

Then, open and close the doors two or three times to make sure that there aren't any gaps between them in the frame. If the doors get stuck, you will likely need to shave off a bit of the weatherstripping so that it's thinner.

5. Look for open spaces and seal them

Next, look at the seam of the doors to see if there are any open crevices or cracks. If the doors have a glass center, be sure to check the seal between the glass and the wood, as the wood can wear down over the years.

Fill the edges of the frame with silicone caulk if you notice any additional cracks between it and the doors. If you're worried about damaging the door, note that caulk can be removed using a scraper tool as well as an adhesive-removing solution such as Goo Gone.

Find Goo Gone on Amazon.

Should there be a gap between double doors?

House interior. View of hallway with french door to office room

Yes and no. There is typically a small gap in the middle of most double doors. The average size of this gap is anywhere from 2 to 5 millimeters. Most of the time this is created because it allows the doors to swing freely without hitting one another, especially if they are located in public areas such as restaurant kitchens, hospitals, or hotels.

If the gap between the doors is bigger than 1/4 of an inch, this can make the doors look a bit unsightly, creating issues with drafts, precipitation, and pests. In cases like this, it's best to seal the door to either close the gap entirely or lessen it—that is, if it's creating a problem.

How do Astragals work?

An astragal is a thin piece of metal (typically aluminum), wood, or silicone used to close the clearance gap between two joining doors. It also helps to deaden the sound of the doors when they close.

Exterior astragals are usually molded and shaped to fit specific door sets, and they're often used in conjunction with weatherstripping.

Does a double door need an astragal?

Not necessarily, though they are often used with double doors. They help seal the gap between the doors, and they are commonly placed in both homes and public buildings to prevent drafts and cold weather from entering the building.

They also work to help with soundproofing rooms. These hardware pieces can be applied to several different door types, including retail establishments, offices, classrooms, industrial applications, and music studios.

How do you put an Astragal on a double door?

Installing an astragal is a fairly simple process. Here are the steps to install one on a double door:

1. Measure one of the doors

Open one of the doors and measure the height of the door from top to bottom. Next, measure the width of the door from the left side to the right side. Write the measurements down on a piece of paper.

2. Cut the astragal

Next, place the astragal on a flat work table or a sawhorse. Then take a hacksaw or small portable saw and cut the astragal to fit the width and length of the door opening. Sand the cut edges with fine-grit sandpaper or a sanding block of about 300-grit.

Find this portable saw on Amazon.

3. Align the astragal to the door

Next, place the astragal on the outer edge of the door where it meets the other door. Align it to the top and bottom of the door so that it lays flush between them. You may need to hold it with one hand while repositioning it with the other.

If the piece does not lay flush against the edge of the door, take it back to the worktable and sand it down or sew off the edges as needed.

Find sandpaper on Amazon.

4. Mark and cut the strike location

Next, take a felt-tip marker and mark the location for both the top and bottom of the door strike on the astragal. Place the astragal back on the work table and cut a piece that's about half an inch on both edges to make room for the strike.

After cutting both pieces, bend the cuts using your hands or a pair of pliers so that the edges snap off easily. This will prevent them from being ripped off.

5. Test the fit and nail the astragal onto the door

Next, position the astragal on the outer edge of the door and line it up again against the cutout area for the strike. Then use brad nails to hammer it into the narrow edge of the door.

Wrapping Things Up

Double patio french doors with windows exiting to sunny backyard

We hope this post has helped explain how to close the gap between double doors. Remember that this gap doesn't necessarily need to be sealed unless it is creating issues with drafts, noise, safety, or pests.

And if you do plan to close it, you can use weather stripping, door sweeps, or an astragal to get the job done. Luckily, it's a fairly simple and inexpensive project to complete.

Before you go, be sure to check out these other posts:

Heil Furnace Leaking Water – What To Do

How Big Is A Heat Pump (And What Size Do I Need)?

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One comment

  1. Problem is finding the astragals. I’m having a hard time finding a simple aluminum t-astragal and when I did find one it was like $100!

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