The rubber strip along the bottom of a garage door is the only thing between the garage and whatever is outside: rain, wind, leaves, and anything small enough to squeeze under. Sun and cold make it brittle, the door's weight flattens it, and eventually it cracks or tears. It's one of the most common and least expensive garage door fixes — and one of the most skipped.
Signs the seal is done
- You can see daylight under the closed door, especially at the corners.
- Water or a line of dirt and leaves inside the door after rain or wind.
- The rubber is cracked, split, or flattened hard instead of soft and rounded.
- Mice, insects, or lizards showing up in the garage.
- A cold draft along the floor in winter.
Seal types
Most steel doors use a T-shaped or bead-shaped seal that slides into a track on the bottom of the door — it's a specific profile that has to match the retainer. Older wood doors use a strip nailed or screwed on. Some doors have an aluminum retainer that's also worn or bent, in which case the retainer gets replaced with the seal. The technician measures the door and matches the profile so it seats properly.
When the problem is the floor, not the seal
A concrete floor that's cracked, sloped, or heaved won't seal against any flat strip. The usual fixes are a thicker seal profile, a threshold seal glued to the floor, or — if the gap is large — leveling the slab. A pro will tell you which one actually solves it instead of selling a seal that leaves the same gap.
What the replacement usually involves and costs
A bottom seal replacement is at the low end of garage door work and is often done alongside a tune-up. If the retainer is bent or the floor needs a threshold, the visit involves more parts and time. Side and top weather stripping can be replaced in the same visit if they're also worn. The technician confirms the price in person after seeing the door and the floor.
Describe the problem — Roger matches you to one vetted local pro and books it. $0 to you.
Common questions
- Why is there a gap under my garage door?
- Usually a cracked or flattened bottom seal. If the seal is fine and the gap is at one end, the concrete floor may be sloped or heaved, which needs a thicker seal or a threshold rather than a standard strip.
- How often should a garage door bottom seal be replaced?
- It depends on climate and use. Sun, cold, and a heavy door shorten its life. Replace it when it's cracked, split, or no longer soft enough to compress against the floor.
- Can a garage door pro fix water coming in under the door?
- Yes. They'll replace the seal, check the retainer, and if the floor is the real cause recommend a threshold seal or leveling — the fix that actually stops the water.