Garage door the chain looks loose or sagging
This is almost always a chain tension has slackened. Repair costs $120 to $280 and takes 30 to 60 minutes. Safe to operate: Yes, but book it.
Check this first — it may cost you nothing
A correctly tensioned chain sits about a quarter to half an inch above the base of the rail at its midpoint. Much more slack than that needs adjusting.
Why this happens
The drive chain stretches over years of use. A loose chain slaps the rail, jerks the door at the start of travel, and eventually jumps the sprocket.
Chains stretch with use. A slack loop under the rail slaps and jerks the door, and it is adjustable at the trolley in a few minutes.
Less likely, but possible
- A worn sprocket, which will not hold tension even after adjustment
- A trolley not travelling smoothly, making the chain surge
- A chain at the end of its life and due for replacement
What happens if I ignore it?
A chain that jumps the sprocket drops the door under gravity. It is also the noise most people notice long before the failure, so it is genuinely cheap to catch.
The repair: opener repair
Garage door opener repair costs $150 to $400 depending on the fault, and takes 45 to 90 minutes. A stripped drive gear or a failed logic board is a repair; an opener over 15 years old is usually worth replacing instead.
Read the full opener repair guide →Get a tech dispatched
Tell us what the door is doing and where you are. We'll connect you with a licensed contractor in your area — usually within the hour.
We pass your details to one licensed contractor serving your ZIP. We don't sell your information to multiple companies. Privacy