There is a sound people remember. A bang from the garage loud enough to be mistaken for something hitting the house, and then nothing. The door looks fine. The opener hums and strains and the door lifts a few inches before giving up. A spring has broken, and the door that weighed almost nothing yesterday now weighs what it has always actually weighed.
That is the thing most people never think about. A sectional garage door is a heavy object, and the opener is not what lifts it. The springs lift it. The opener only guides a door that the springs have already made nearly weightless. Once a spring goes, nothing else in the system is sized for the job.
Two systems, two completely different repairs
Almost every residential door uses one of two spring arrangements, and they behave differently enough that it is worth knowing which one is over your head.
Torsion springs
A horizontal shaft above the door opening with one or two springs wound around it. As the door comes down, cables wind the shaft and the springs twist, storing energy. As the door rises, that energy is released. Torsion is the more common modern arrangement, it runs more smoothly, and it is the one that fails with a bang.
A broken torsion spring is easy to identify from the ground: you will see a visible gap of two or three inches in what should be a continuous coil.
Extension springs
Long springs running parallel to the horizontal tracks on each side, stretching as the door closes. Older installations and lighter doors often use these. They are cheaper, they tend to be noisier, and they are less consistent in how evenly they lift.
Extension springs have a specific hazard that torsion springs do not: when one snaps under tension, the spring itself can travel. That is what the safety cable running through the middle of the spring is for, and it is the first thing to look for on an older door — if there is no cable through the spring, that is a problem regardless of whether anything has broken yet.
Why springs break, and why it is rarely sudden
Springs are rated in cycles. One cycle is one open and one close. They are a wear item in the truest sense — the steel fatigues a little every time it is loaded, and eventually it fatigues through.
What shortens that life is worth knowing, because most of it is controllable:
- Usage. A door used as the main household entrance cycles several times what a door used twice a day does. The spring does not know why it is cycling.
- Cold. Steel is less forgiving at low temperatures, which is why Ontario springs disproportionately break on the coldest mornings of the year rather than randomly through the season.
- Corrosion. Road salt carried in on a vehicle, humidity, and bare steel are a bad combination. Rust creates the surface pitting that fatigue cracks start from.
- Bad balance. A spring that was undersized or badly adjusted at installation works harder than it should every single cycle.
Lubrication genuinely helps here — not on the wheels or the track, but on the spring coils themselves, where it slows corrosion and lets the coils move against each other instead of binding.
Why both springs get replaced when one breaks
This is the part that sounds like an upsell and is not.
On a two-spring door, both springs were installed on the same day, carry the same load, and have cycled the identical number of times. When one reaches the end of its fatigue life, the other is at the same point in its own. Replacing one means the second will typically break within a fairly short window — and on a day of its choosing.
There is a mechanical reason as well. A new spring and an aged spring do not deliver the same force. Pairing them leaves the door lifting unevenly, which loads one side of the track, one cable and one set of rollers harder than the other. That asymmetry is what turns a spring job into a cable and drum repair six months later.
The labour is almost entirely in setting up and winding. Doing it twice costs far more than doing it once.
The honest warning about doing it yourself
This is one of the few genuinely dangerous jobs in home maintenance, and the reason is specific rather than vague.
A torsion spring is wound under extreme tension using two steel winding bars. If a bar slips, is the wrong diameter, or is substituted with a screwdriver, it becomes a projectile and the spring unwinds in a fraction of a second with a grown adult’s hands in the path. The injuries from this are serious and well documented across the trade.
Extension springs carry a related hazard at the anchor points. Replacement is a controlled job in both cases, and it depends on correctly identifying the wire gauge, inside diameter, length and wind direction before anything is touched. Getting any of those wrong produces a door that is unbalanced from day one.
Plenty of garage door work is reasonable for a competent homeowner — tightening hardware, replacing rollers, adjusting sensors, replacing weatherstrip. Spring replacement sits on the other side of that line.
What a correct spring job includes
Fitting the spring is the middle of the job, not all of it. A complete replacement should also cover:
- Measuring the door, not guessing it. Wire gauge, inside diameter, overall length and wind direction determine the spring. These come from the old spring and the door weight, not from a catalogue default.
- Inspecting the cables and drums. A spring that broke under load often frayed a cable on the way out. Frayed cable is a failure waiting to happen.
- Checking the bearings and the shaft. Worn end bearings make a grinding noise and chew through the next set of springs faster.
- Balancing the door. With the opener disconnected, the door should stay put when released at roughly waist height, and should be liftable by hand with moderate effort. If it slams down or flies up, the tension is wrong.
- Re-testing the opener’s safety reverse. The opener’s force settings were calibrated against the old spring balance. They need checking against the new one.
That balance test at the end is the single best indicator of whether the job was done properly, and it takes thirty seconds to watch.
Signs a spring is near the end
Springs do give warning, if quietly:
- The door feels heavier by hand than it used to
- It opens unevenly — one side leading the other
- The opener works noticeably harder, or the door jerks on the way up
- Visible gaps are opening between coils when the door is closed
- Rust, flaking or pitting along the coil
- The door no longer holds position when stopped halfway
Any two of those together are worth an inspection before the bang rather than after. If the door has reached the point of not moving at all, it is a full garage door service call rather than something to keep forcing with the opener — every attempt to drive a door against a broken spring puts the strain somewhere else in the system.
Frequently asked questions
Can I use the opener until the spring is replaced?
No. The opener is not built to lift the full weight of the door, and forcing it burns out gears, strips drive components and can pull the opener’s mounting out of the ceiling. Disconnect the opener and leave the door closed.
Can I lift the door by hand with a broken spring?
It is far heavier than people expect and there is nothing holding it up once it is raised. If the vehicle absolutely has to come out, that is a job for more than one person, with the door propped securely — and it is still not a good idea.
How long should new springs last?
Springs are sold by cycle rating, and the honest answer depends on how many times a day the door is used. A door opened twice daily and a door opened ten times daily will reach the same cycle count at very different dates. Higher-cycle springs cost more up front and are usually worth it on a door that is in constant use.
Why did my door go crooked after the spring broke?
Uneven lift pulls one cable off its drum. That is a separate repair from the spring, and it needs correcting at the same time or the new spring will be fighting a misaligned door immediately.
Are torsion springs better than extension springs?
For most doors, yes — smoother operation, better balance, better behaviour at failure. Conversion is possible on many doors but needs adequate headroom above the opening, so it is not universally available.
The short version
A broken spring is not a sign the door is finished. It is a wear part reaching the end of a predictable life. Replace both, check the cables and bearings while everything is apart, and test the balance before the opener is reconnected — and the door goes back to feeling weightless, which is how it is supposed to feel.
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