Garage door too heavy to lift by hand?

A residential door weighs well over a hundred pounds, and often a lot more with insulation or glass. You are not meant to lift that weight. The springs are, and a counterbalance system is set so the door feels close to weightless in your hands. When it does not, the springs are no longer doing their job.

The usual reasons are a torsion spring that has already snapped, or one that has stretched and lost tension after many open-and-close cycles. With two springs, one can break while the other keeps the door feeling only a little heavy at first, which is why many people do not notice until the second one goes. Rust, dry air, and cold Colorado mornings do not help an old spring.

One thing worth saying plainly: the opener is not meant to be lifting the door's weight. If you have been relying on it to haul a heavy door up, it is working far past what it was built for, and the motor, gear or belt will pay for it. Our answer on whether springs or the opener lift the door explains the split.

If one spring has broken, we usually recommend replacing both. The second one has worn the same number of cycles and tends to follow soon. Our answer on replacing one spring or both goes through it.

If the door itself is damaged or has been loaded with extra weight, such as an added panel or insulation kit, the springs may need to be sized to match. In rare cases an old door is worn enough that a new door makes more sense, and we will say so.