Updated on Jan. 10, 2025
Think of the bottom seal as weatherstripping for your garage door. It keeps out cold air and rain and maintains a comfortable climate in the garage.
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Most homeowners understand the need for weatherstripping doors and windows to prevent heat transfer and lower energy bills. But you may not realize it’s just as important for the garage door, particularly the bottom.
When I was younger, I used our family garage as a workshop. The wind whipping through the bottom of the door made it impossible to work there in the winter unless I stuffed rolled-up towels in the gap. A new bottom seal would have done the job more efficiently.
If you can see daylight between the garage flooring and the bottom of the door when it’s closed, you’re probably experiencing one or more of the following problems:
Garage door bottom seals are usually made from vinyl or rubber, and they do wear out. If you have an older garage door, it’s possible part of the seal is intact while another is cracked, allowing air and water to pass through.
Replacing a worn seal is a straightforward DIY job as long as you disconnect the door from the automatic opener, open it halfway and clamp it to the rails. Plus, you have to get the right seal. That depends on the thickness of the door and the condition of the garage floor.
It also depends on whether the door comes with a retainer, i.e. a metal or PVC bracket that attaches to the underside. Tracks hold the bottom seal to the door. If the door lacks a retainer, you can install one yourself. If the existing retainer is damaged, replace it.
You can usually order a new bottom seal specifically designed for your door from the manufacturer. If you don’t know the brand, there are many generic options.
Here are the most common types of garage door bottom seals.
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Like a sweep for your front door, a self-adhesive weatherstrip attaches to the bottom of the door on the outside. When the door closes, the rubber seal presses against the pavement and splays outward to make the seal.
This type of weatherstripping works best for wooden canopy and retractable doors that swing out and up when you open them. You can also use this on sectional and rolling doors.
There are easy to install. Close the door, position the strip, peel off the backing, stick it in place and drive screws to hold it on permanently.
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The U-shaped beaded door seal is a flat piece of rubber or vinyl with beaded edges. It fits into tracks on a retainer installed on the bottom of the door. The strip is wider than the door’s thickness. Fitting it into the retainer tracks creates a U shape that compresses against the pavement when the door is closed.
This type of garage door bottom seal works well on uneven pavement, because the material is flexible enough to fill depressions. It is available in widths from three to six inches, and you can compensate for deep depressions by choosing a wider strip.
It requires a matching retainer that’s standard on metal doors from some manufacturers, but may have to be installed on other doors.
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A bulb-shaped bottom seal, aka a tube seal, is a length of rubber or rubberized vinyl formed into a closed loop with a circular or oval cross-section. A channel on the top of the loop fits into a corresponding track in a retainer affixed to the bottom of the door.
This type of seal flattens against the pavement when the garage door is closed, effectively sealing out the elements. It’s similar to the action of a beaded seal. But because it only requires a single track, it’s best for doors that already have that kind of retainer. For two-track retainers, you can find a bulb-shaped seal to fit that.
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Almost every outlet that sells garage door seals lists T-style as an option. This refers to the shape of the channel that fits into the track on the retainer. The T-style cross-section makes the seal watertight and prevents it from moving laterally and interfering with the operation of the door.
Both bulb-shaped and U-shaped beaded seals come with rounded and T-shaped channels. If you have an existing retainer, be sure to check the shape of the tracks before you buy the door bottom sealer, because rounded and T-style tracks aren’t interchangeable.
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A J-style bottom seal fits into a single-track retainer. It consists of a flap that bends to form a shape like the letter “J” when the door is closed. Some versions have two flaps; one bends toward the outside of the door, and one toward the inside.
This type provides good protection from rain and wind. Because it often comes with its own retainer, it’s a good option for a wooden garage door without one. The retainer width must match the door thickness. You install it by fitting it onto the bottom of the door, then nailing or screwing it to the outside.
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Sometimes the floor underneath the garage door is too uneven for a bottom seal to close all the gaps. A good remedy is a garage door threshold seal on the floor.
Usually made of rubber or vinyl, the threshold elevates in the middle and tapers off on both sides. It’s tough enough to withstand vehicular traffic. When installed correctly, it effectively seals the bottom of the door all by itself. It’s more effective when used with a bottom seal.
It’s even easier to install a threshold than a door seal. Cut it to length, position it, mark the outline, spread adhesive in the outline and set the threshold in the adhesive. Seat it firmly with a few taps with a hammer.
