Garage door daylight or a gap under the closed door
This is almost always a bottom seal has hardened and taken a flat set. Repair costs $90 to $220 and takes 30 to 60 minutes. Safe to operate: Yes.
Check this first — it may cost you nothing
Look along the bottom with the door closed. If you can see daylight, or the rubber looks flattened and cracked rather than rounded, it needs replacing.
Why this happens
The U-shaped rubber seal in the retainer along the bottom rail compresses to fill the gap. Over time heat hardens it and cold makes it brittle, until it stops springing back and simply sits flat.
A hardened seal takes a set and stops conforming to the slab. The gap you can see is the draft, water and pest route.
Less likely, but possible
- An uneven concrete slab, which needs a threshold seal rather than a door seal
- The door sitting slightly high because of a close-limit setting
- A bent bottom rail from an impact
What happens if I ignore it?
Water, dust, leaves and rodents get in — a quarter-inch gap is enough for a mouse. In a heated garage the running cost is real, and in freezing climates standing water at the base leads directly to the door icing shut.
The repair: weather seal
Garage door weather seal replacement costs $90 to $220 installed for a bottom seal, or $150 to $350 for the full perimeter. Seals last five to ten years and fail sooner in high-heat and high-freeze climates.
Read the full weather seal guide →Get a tech dispatched
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