

Springs · Oakville
Extension Spring Replacement
The home inspector's report on the house you are buying flags the garage door: extension springs with no safety cable running through them, coils showing rust, and a door that sank when he lifted it partway.
In plain words
Garage doors are balanced by one of two spring systems, and the extension kind is the one you find on many single-car doors and older detached garages. Instead of a spring wound on a shaft above the opening, an extension system uses two springs stretched along the horizontal tracks, working through pulleys and cables. It needs less headroom, which is why it suits garages with a low ceiling. Replacing these springs is its own service with its own parts: springs chosen by door weight, pulleys, S-hooks and containment cables. A technician confirms which system is on your door before any part is chosen.
How the visit goesThe home inspector's report on the house you are buying flags the garage door: extension springs with no safety cable running through them, coils showing rust, and a door that sank when he lifted it partway. The seller has never had it looked at.
Extension Spring Replacement
How the visit goes


Containment cables, present or missing
The question the industry's own inspection checklist asks of every extension-spring door is whether each spring has a cable running through its centre, anchored at both ends. The technician checks for it on both sides, then checks its condition: a cable that is frayed, kinked, anchored to a loose screw or simply tied off to the hanger is not doing its job. Doors installed decades ago often have none at all, and doors that had a spring changed by a previous owner sometimes have one side fitted and one forgotten. Fresh containment cables go on with the new springs, and their anchor points are set into solid framing so that a spring which breaks stays on its cable.
Taking the old springs down
With the door open and clamped, each old spring is nearly slack, and removal is straightforward. The technician unhooks the lift cable from its S-hook or clip at the front, which lets the spring's pulley end drop free, then lifts the rear loop off the hanger. The old containment cable is unclipped from its anchors and pulled out of the coil. On a door with a broken spring, the two halves are gathered and the containment cable, if there was one, is inspected for the marks of having done its job. Everything that comes down is laid out on the floor so the old spring can be measured against its replacement and you can see the wear.
Knowing when the next set is due
A standard extension spring is made for a set number of open-and-close cycles, commonly in the ten-thousand range, which on a door used four times a day works out to several years and on a door used twice a week to much longer. Springs age even when idle, as rust does its slow work in an unheated garage. The signs that the set is nearing the end are gradual: the door feels heavier by hand, the opener sounds as if it is working, the door drifts down from halfway, and gaps appear between coils when the door is open. Acting on those signs turns the next replacement into a planned appointment rather than a bang in the night.
Extension Spring Replacement
In the van
Extension springs, matched pair
Garage-door spray lubricant
S-hooks and adjusting clips
Bottom brackets and clevis pins
Containment (safety) cables

Extension Spring Replacement
What affects the quote
Opener adjustment and testing
Resetting the opener's force and travel to the newly balanced door and running the reversal tests is a short task that the quote names when it applies.
Condition of the lift cables
Cables with fraying, rust at the loop or a kink are renewed as a pair while the springs are off. Sound cables are re-routed and set, and the quote says which applies.
Converting to torsion instead
Where the garage has the headroom, some owners take the opportunity to move to a torsion system. That is a different job with different hardware and is quoted as its own option.
What to have ready
- Is there anything stored beside the tracks or under the springs?
- Is a car parked inside that will need to come out first?
- Is there a thin cable running through the middle of each spring?
Extension Spring Replacement: questions
QuestionsShould I try to open the door by hand before the technician arrives?
No need, and it is easier on the door if you leave it. With a spring broken or slack, the door is unbalanced and heavy, and lifting it can let it drop or twist a section in the track. If the door is stuck partway, leave it there and keep people and the car away from the opening. The technician brings clamps and props, and the door is secured before it is moved at all.
Will the lift cables be changed as well?
They are inspected every time and changed when they show fraying, rust at the bottom loop, or a kink from having jumped a pulley. Cables and springs are generally the same age, and with the door already open and the springs off, fitting new cables adds little to the visit. Bright, tight strands with clean loops can stay and are simply re-routed over the pulleys and set to the new springs.
I added insulation and windows to the door. Does that affect the springs?
Yes, and it is one of the more common reasons a pair of springs is suddenly found wanting. Insulation panels, glazed sections, a wood overlay or a new steel skin all add weight the original springs were never chosen for, so the door grows heavy and the opener strains. When the springs are replaced, the door is weighed as it is now, and the new pair is rated for the door you actually have.
Related services

- Garage Door Hinge ReplacementThe roller at the top of the second panel is leaning outward and only half of the wheel is still in the track.
- Garage Door Track Repair or ReplacementThe door climbs crooked, one side clearly ahead of the other.
- Garage Door Cable ReplacementYour older door has springs along the tracks, and one cable has slipped off its pulley and dangles slack.