Here are the bands first, because that is what you came for. One torsion spring, wound and fitted in Franklin, is an estimated $185 to $345. Do both on a double door as a matched pair and it is an estimated $265 to $450. An older door still hanging on extension springs is an estimated $155 to $275 for the pair. Stepping up to high-cycle steel adds an estimated $60 to $120 apiece. All guide figures rather than a quote, and where your job lands inside them is decided at the door, not on the phone.
Where the money in that band goes
Not much of it is steel. A spring is a coil of wire; the cost is the sizing, the winding and the setting up afterwards. A fair invoice pays for the door being clamped and any remaining shaft tension bled out with proper winding bars, the spring sized against the actual weight of the door, the winding taken to a calculated turn count, the balance proved by hand with the opener disconnected, the cables and drums looked over while the shaft is accessible, and the opener force and both travel limits reset with the reversal test run afterwards. Take any of those out and the price falls. So does the life of the repair.
Four measurements come off the broken spring
- Wire diameter. The thickness of the steel itself, commonly between about 0.207 and 0.283 inches on a house door. Thicker wire carries more weight and costs more.
- Inside diameter of the coil. Usually 1.75, 2.00 or 2.625 inches. These are separate families of spring, not sizes of the same one.
- Relaxed length. Taken with the two broken halves pushed back together so the coils that are missing get counted.
- Wind direction. Left hand or right hand. Fit the wrong one and it unwinds where it should lift.
Those four get read against the weight of the door, which is why the door gets lifted and felt before parts come off the van. A light single steel door from the 1970s and a three-layer insulated double on a Westhaven three-bay front are not the same job, even when the broken spring looks similar from the driveway.
Why Franklin springs rarely see their rated count
Springs are rated in cycles, not years. Ten thousand is the builder standard, which works out at seven to twelve years for a household opening the door four or five times a day. Plenty of springs here fall short of that, and the reason is sitting in the coil gap.
An unconditioned garage in a humid climate is a rusting environment for bare steel. Rust forms in the narrow gap between adjacent coils, and once it is there the coils rub instead of sliding. That friction takes a small bite out of the spring on every cycle, so the count runs down faster than the calendar suggests. Then winter arrives and crosses freezing and comes back, over and over rather than settling in, and the first properly cold morning is when a tired spring lets go. The cold gets the blame. The cold is the trigger; the corrosion did the work. A light coat of garage door lubricant on the outside of the coils, wiped down, is cheap insurance in this climate.
One spring or both
On a two-spring door, both have taken the same cycles and the same damp. When one breaks the other is normally months behind, not years. Fitting one leaves you a second call-out and, worse, uneven tension across the shaft, which racks the door in the tracks and chews the rollers on one side. In the 1990s and 2000s subdivisions around Fieldstone Farms and McKay's Mill, whole streets are working through a second set of springs at similar rates, which is why neighbors end up comparing notes inside the same few weeks.
What belongs on the invoice
Wire size, inside diameter, length and cycle rating of what was fitted. Labor separated from parts. The rate tier stated, standard or after hours. And two durations: a parts warranty and a labor warranty, written separately, because the manufacturer covers the part and the company covers the work.
That last point carries more weight in Williamson County than most homeowners realize. Tennessee's Home Improvement license, which covers residential work between $3,000 and $24,999, applies only in the nine counties that adopted the law, and Williamson is not one of them. The contractor's license proper starts at $25,000. So for a spring job in Franklin there is no state trade license to check. Proof of current general liability insurance and a warranty you can read are the real backstop.
Why nobody sensible winds their own
A wound torsion spring holds hundreds of foot-pounds of energy and gives it up faster than a hand moves. A winding bar that slips out of a cone breaks bones. Screwdrivers and offcuts of rebar are not winding bars, and the spring kit sold online is cheaper than a fitted price for reasons that have nothing to do with the steel. If the door is down and the garage is secure, book the morning slot at the standard rate rather than paying the after-hours rate tonight. Same spring, same work, less money.