Broken or weak spring
Without enough spring tension, the door falls under its own weight.
Springs and balance
Garage Door Slams Shut
A door that drops quickly or slams onto the floor is usually not being held by its springs properly. It can injure someone and damage the door, so it needs prompt attention.
Short answer
The most common cause is a broken or weakened spring, or a cable problem. Less often, the opener's limit or force settings are off. If the door slams, stop using it, keep people clear and book a technician to check the springs and cables.
Likely causes
Cable damage
A frayed or slipped cable can let one side drop.
Opener settings
Incorrect limits can make the opener drive the door hard into the floor.
Manual release pulled
A door released from the opener with weak springs can drop. See balance adjustment.
A door that slams is often more dangerous when the opener is disconnected, because the opener's rail can hide weak springs by controlling the descent. If someone pulled the manual release and the door fell, that is a strong sign the springs need attention before the door is used again.
Safe checks you can make
- Look for a gap in the torsion spring
- Check for loose or frayed cables
- Note whether the opener is still connected
Stop and call a technician if
- The door drops quickly
- A spring or cable looks broken
- The door is uneven
What a technician may inspect
- Springs and cables
- Door balance
- Opener limits and force
- Bottom brackets and drums
Describe what the door is doing when you call. A provider may ask follow-up questions, but a reliable price normally needs an on-site look rather than a phone-only quote.
Services that address this problem
Garage Door Spring Replacement
Most homes have torsion springs on a shaft above the door or extension springs that run along the horizontal tracks.
Garage Door Balance Adjustment
Springs are sized and tensioned to offset the door's weight.
Garage Door Cable Repair
On a torsion system, cables wind around drums at each end of the shaft.
Frequently Asked Questions
Most often a spring is broken or weak, so it cannot slow the door. A cable issue or opener setting can also be involved.
Yes. A heavy door dropping quickly can injure someone or damage a vehicle. Stop using it until it is repaired.
Not if the springs are the problem. Adjusting opener settings will not replace missing spring tension and can make things worse.
With weak springs, the door may drop suddenly when released. Only pull the release with the door closed if possible.
Repeated slamming can crack panels, bend the bottom section and damage hinges and rollers.
As soon as practical, because the door is unsafe. Keep it closed and avoid using it until repaired.
Get your garage door working safely again
Call to schedule a technician visit with an independent provider who serves your area.