A loud bang, then a door that will not lift, usually means a broken torsion spring. The spring carries the door, not the opener, so the opener hums and nothing moves. Hire a pro. It is usually a repair, not a new door.
The motor is still trying, but the door can weigh a hundred plus pounds. The opener cannot hoist that alone.
Look up. The coil lives on a shaft above the opening. Two car doors often have a pair. One car doors often have one. That steel does the heavy work, not the wall button.
If you heard a bang and the coil has a gap or sits collapsed
Pull the emergency release only for a second check, and stand clear of the panel. A balanced door still moves by hand. This one feels like a brick. Look at the coil from the side, not under it. Sometimes there is a clean gap in the steel. Sometimes one spring has collapsed next to its pair. That is the classic snap. Stop mashing the remote. Every cycle that fights a dead spring cooks the opener.
If the door sits crooked after the bang
Cables wrap drums at both ends of that shaft. When the spring snaps, a cable can go slack or take a shock it was never meant to take alone. The door can list, drop a corner, or leave a track. If one side hangs lower, or a cable looks frayed or jumped a drum, treat it as spring and cable work together. Stay out from under it. Do not shove a roller back in with a screwdriver.
If there was no bang but the door still feels like a brick
Not every dead spring announces itself with a crack. A spring near the end of its cycle life can fade until the opener strains every morning. Springs are wear parts, rated in cycles, not calendar years. Cold is often the last straw. Steel shrinks. Salt pits rollers and the bottom seal, which adds drag. If yesterday it moved and today it is a brick, treat it as spring or cable until a technician says otherwise.
What it is not
This is different from a remote that does nothing. A silent remote morning means batteries, lock mode, or a dead board. No hum. No rail travel. Here the opener usually wakes and strains while the door barely moves.
It is also different from an opener that grinds like gravel. That noise lives in the motor head. A spring snap is a single bang, then dead weight. The head may hum clean while the door refuses to climb.
A door that starts closing then climbs back up is close reverse. Eyes, travel, or force. Not a coil that let go overnight. A door that hangs halfway with no bang can be ice, track, cable, or spring. Use the hand test. Brick weight points at the spring. A bind or list with nested rollers points elsewhere. See also stops short.
What not to do
Hire a pro. Do not wind the spring yourself. Do not stand under a door that is off its tracks. Do not brace a board or your shoulder under it. The winding cones hold enough energy to wreck a hand. Cables can whip. If it is open and will not close, keep people and cars out of the opening and call someone. If it is closed, leave it closed and use the house door. Do not climb a ladder with locking pliers and a YouTube clip on your phone.
Usually this is a repair, not a new door. Replace the broken spring, and often its pair so they wear together. Inspect the cables and drums. Rebalance. Then test the opener. The opener may still be fine. Mark a full replacement door separately if you request a quote.
I am not a contractor. This is what shows up when people hear one bang and start shopping for a whole new door. A shop will confirm the spring, check the cables, and say whether the opener survived before they sell you a full door.
Industry manufacturers publish torsion spring guidance through the Door and Access Systems Manufacturers Association (DASMA). Those notes are for dealers and installers, not DIY winding. Hire a pro.
The U.S. CPSC garage door operator page covers federal rules for automatic openers. A spring that lets go turns a powered door into a heavy panel. Leave the cones alone.
If the panels themselves are shot and you are weighing a full new door, the national Cost vs Value Report tracks typical garage door replacement cost and cost recouped figures. Those are national averages, not a local quote from this site.
If yours bangs and will not lift, get a quote.