At the base of the door, the bottom seal is the component most subject to wear and tear. It presses against the floor every time the door closes, passes through puddles, endures freezing temperatures, and remains exposed to dirt. Unsurprisingly, it is the first seal to fail, and its replacement is one of the most frequent maintenance tasks for a sectional door.
However, choosing the right seal is essential. There are two main types, depending on how it inserts into the door panel. This article explains how to distinguish between them, how to take measurements, and how to replace them. For an overview, see our guide to sectional door seals.
The role of the bottom seal
The bottom seal is attached under the last panel and compresses against the floor when closing. It seals the gap between the door and the floor, even if the surface has slight irregularities. It prevents water, leaves, dust, and small animals from getting in, and limits cold air infiltration.
It also acts as a shock absorber: by touching the floor gently, it reduces impact and noise during closing. When it hardens or tears, all these benefits vanish. A bottom seal in good condition also contributes to the effectiveness of the motor's obstacle detection system by providing a soft contact surface.
Two insertion methods: aluminium profile or panel
Depending on the manufacturer, the bottom seal is housed in one of two ways. In the first case, it slides into an aluminium profile attached under the panel: this is the case for the bottom seal compatible with La Toulousaine, BKF, and FAME. In the second case, it slides directly into the panel, like the bottom seal compatible with SDA, BKF, and Sectiotech.
To find out which one you need, lift the old seal and observe the shape of its base: is a metal profile visible? Does the seal slide into a groove in the panel itself? Take a photo of the seal's cross-section from the front: this is the best way to compare it with our product pages. If you do not know the make of your door, refer to our article on identifying your door brand.
Measuring the length to order
Our seals are sold by the meter, so you simply need to indicate the length required. The easiest way is to measure the old seal or the width of the door if the old one is too damaged. Measure it flat, without stretching it, and add a small margin to trim it cleanly to size.
If your door is wide, check that the total length is supplied in one continuous piece or can be assembled without a visible break. For industrial doors, use the bottom seal for industrial doors: the specifications are different (see our article on industrial vs. residential doors).
Replacing the bottom seal step-by-step
The operation is accessible and does not affect the springs or cables. Close the door, disconnect the motor, and stay inside the garage. Remove the old seal by sliding it out of its groove, starting from one end. Clean the groove or profile to remove dirt and rubber residue.
Position the new seal, insert the end into the groove, and slide it across the entire width. A little soapy water on the tab makes insertion easier. Cut off the excess to the right length with a utility knife. Then, test the closing: the seal should touch the floor without scraping it, and the door should not bounce back.
Other components to check at the same time
Take advantage of the replacement to check nearby components: side seals, rollers, bottom brackets, and corner consoles. A worn side seal lets in as much air as a faulty bottom seal: see sectional door side seal. To renew all sealing at once, the sealing repair pack is a great option.
If, despite a new seal, water or air still get in, look for the cause elsewhere: uneven floor, misaligned door, or door adjustment issues. Our article on cold, air, and water details potential solutions.
Conclusion
The bottom seal is the most exposed sealing component of your sectional door. Identifying its insertion method (aluminium profile or panel), measuring the length, and choosing the compatible part allows for easy replacement, without the need for specific tools.
Our catalog of sealing gaskets covers all major configurations. If in doubt, a photo of your seal's cross-section is enough to identify it.
FAQ: Bottom seal
How do I know if my bottom seal fits into a profile or the panel?
Remove one end of the seal and look: if a metal profile is attached under the panel, it is an aluminium profile. Otherwise, it slides directly into the panel.
What length of seal should I order?
The width of the door or the length of the old seal, with a small margin. Our seals are sold by the meter.
Can the bottom seal bridge an uneven floor?
It compensates for minor irregularities, but not a significantly uneven floor. In that case, a door adjustment or a floor threshold may be necessary.
Can I replace the bottom seal without dismantling the door?
Yes, the operation is done with the door closed by sliding the old seal out and the new one into the groove.