In winter, you feel a draft as soon as you open the garage door leading into the house. After a rainstorm, a puddle spreads under the door panel. In autumn, leaves accumulate in the corners. These symptoms have a cause: the door's seal is no longer effective. The good news is that you can almost always restore it, often at a low cost.
This article reviews the most common causes of leaks, from the simplest to the most technical, and offers concrete solutions. It complements our guide to sectional door seals.
A worn bottom seal, the number one cause
In the vast majority of cases, the bottom seal is at fault. It has hardened, cracked, lost its shape, or partially detached. It no longer fills the gap between the door panel and the floor. The signs are easy to spot: light visible under the closed door, seal crushed on one side, or tears.
The solution is replacement, a simple and inexpensive operation. Depending on the design, the bottom seal inserts into an aluminum profile or into the panel itself: see our article on sectional door bottom seals and our two references, the aluminum profile bottom seal and the in-panel insertion bottom seal.
Defective side or header seals
Air leaks often occur through the sides or the top. A hardened or detached side seal leaves a gap along the frame, and a worn header seal creates an opening at the top. Perform the light test during the day, with the door closed, from inside the garage.
For the sides, we offer the side seal compatible with Gypass, BKF, FAME and the side seal compatible with Safir, Lépinard, Gypass, BKF. Our article on sectional door side seals explains how to choose and install them. To replace everything at once, our seal kit may be suitable.
Adjustment issues or a misaligned door
If the seals are in good condition but air still gets through, check the adjustment. A door that does not close completely, is slightly crooked, or has poorly positioned rollers will leave a gap on one side. In this case, the bottom seal does not touch the floor across its entire width.
Check the position of the panel, the condition of the cables and springs, and the operation of the motor's limit switch. An incorrect limit setting can leave the door a few centimeters above the floor. Consult our article on crooked garage doors and our guide on cables, drums, and pulleys to detect the source of the fault.
An uneven floor or missing threshold
A sloping floor, damaged concrete, or a depression in front of the door prevents the bottom seal from pressing down effectively. Rainwater then gets in easily. In this case, the seal alone cannot compensate for everything: adjusting the threshold, leveling the floor, or adding a water-resistant threshold may be necessary.
A thicker bottom seal or one with a softer lip may help, provided it remains compatible with your door profile: never install a seal that does not insert correctly. If you have any doubts about the slope or necessary repairs, seek the advice of a building professional.
The right habits to keep a door sealed
Regular maintenance limits leaks. Clean the seals with soapy water twice a year, remove leaves and debris at the base of the door, and check the flexibility of the seals at each change of season. A light lubrication specifically designed for rubber helps preserve its elasticity.
Find the annual checks to perform in our article on annual sectional door maintenance. References can be found in our seals collection, with the option for a complete renewal.
Conclusion
Cold, air, water, and dust under the door are almost always caused by worn seals, approximate door settings, or an uneven floor. In most cases, replacing the seals is enough to get your garage protected again.
Perform the light test, take measurements, identify the seal model, and then choose the compatible reference. Our team can guide you if you provide a photo of your seal.
FAQ: leaks under the door
Why is water getting under my garage door?
Most often due to a worn bottom seal or an uneven floor. If the seal is in good condition, check the limit switch setting and the alignment of the door.
Is a new seal enough to stop drafts?
In most cases, yes, if the fault lies with the seal. If air is still getting through, check the side seals, the door top, and the adjustment.
How do I test the sealing of my door?
Close the door and stand in the garage in broad daylight: if you see light around the edges, air is getting through as well.
Should all the seals be replaced at the same time?
Not necessarily. If the door is old, a complete renewal ensures uniform sealing and prevents having to perform multiple repairs.