Quick Answer
If your garage door bottom seal has a gap on one side, the most common reasons are an uneven garage floor, a worn seal, or door alignment issues that prevent even contact.
Most Likely Causes (Ranked)
- Most common: Garage floor is slightly uneven or sloped.
- Also common: Bottom seal is worn, stiff, or damaged on one side.
- Less common: Door alignment issue (door not meeting floor evenly).
How to Narrow It Down (Safe Checks Only)
- Check if the gap changes when the door closes fully (consistent vs intermittent).
- Look at the seal: cracks, missing sections, stiffness.
- Check whether the door looks level when closed (visual tilt can signal alignment issues).
- Confirm the gap is not caused by debris at the floor line.
What NOT to Do
- Don’t adjust springs/cables to “level the door.”
- Don’t force the door tighter if it causes strain or reversing.
When to Stop and Call a Pro
If the door binds, reverses, or seems unbalanced, stop and call a pro. Unbalanced doors can be hazardous and may indicate a safety risk. CPSC garage door safety publication (PDF)
Helpful Links
FAQs
- Is a small gap a big deal? It can increase drafts and pests. If the door also reverses or binds, treat it as a safety issue.
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