Garage door springs offset the weight of a garage door and allow the door to be opened and closed easily, either by hand or by an automatic garage door opener. The high-tension steel in the springs has a limited lifespan, and over time, the springs lose their effectiveness. Many homeowners choose to have this work done by professionals since there working with springs under tension is potentially dangerous. However, it is entirely possible for a moderately skilled and careful DIYer to do the work themselves and save money.
Whether you do it yourself or have a pro do it, remember that garage door springs come in levels of quality—they may be described as "10,000-use" or "20,000-use" springs, for example. This may sound like a very large number, but when you consider that a garage door might be opened four or five times a day, every day, every year, it becomes clear that there is a limited lifespan for these critical garage door parts. It's usually wise to buy quality parts since this is a job you'd rather not do too often.
Two Types of Garage Door Springs
Most residential garage doors have one of two types of springs: torsion or extension. Torsion springs are heavy-duty springs mounted around a metal rod (a torsion rod) that runs parallel to the door, directly above the door opening. Extension springs are long, lighter-weight springs that run perpendicular to the door and are mounted above the horizontal portions of the door tracks. As with the torsion system, these springs are tensioned by stretching out, using cables and pulleys.
When preparing to replace garage springs, it's critical that you buy the right style of springs, in a length and diameter that matches the old springs.
How Garage Door Springs Work
The typical sectional garage door operates by means of pulleys, cable, and springs. The cable transfer the energy of the springs to move the weight of the door, while the pulleys serve to reduce the effort needed to lift the doors and control the direction of the force.
If your garage door uses extension springs, there will be two sets of pulleys and two cables on each side. One end of the first cable is anchored to the bottom of the door, then runs up and over a stationary pulley attached to the wall near the upper corner of the garage door, around a moveable pulley attached to the end of the spring, then back to an anchored bracket secured to the door track. As the door closes, the pulleys and cable stretch out the spring, creating tension that will assist in lifting the door when you next open it.
However, there is also another cable on each side of the garage door, which runs through the middle of the spring and is anchored to track brackets on each end. These are safety cables that keep the spring in place if it happens to break under tension. These safety cables are mandatory safety features, and if your door springs are not fitted with these, it is essential that you install them (or have them installed professionally) when you replace the springs.
If your garage door has torsion springs above the garage door opening, one end of each spring will be firmly anchored to a center plate, usually attached to the garage wall above the door. (Small garage doors may have only one torsion spring, not two). A torsion bar runs through the center of each spring, with the far ends fitted with a cable drum that holds the lift cable that runs down to secure to a bracket attached near the bottom corner of the door.
The free end of the spring is firmly anchored to the torsion bar by means of a winding cone. As the door closes, the extending cable causes the winding drum and torsion bar to rotate and twist the spring into a loaded, "torsioned" state. When the door is next opened, the tension on the springs is released in a controlled fashion to assist in lifting the heavy door to an open position.
With either type of springs, hundreds or thousands of opening and closing cycles will cause the metal in the springs can lose its resiliency, gradually approaching a condition where they will need to be replaced.
Symptoms of Failing Springs
Aging garage door springs cause the door to effectively "weigh" more as the steel loses its resiliency. With new springs, a heavy garage door should take no more than about 10 pounds of force to lift into an open position. With springs nearing the end of their lifespan, the force required to lift the door can be considerably more, since a garage door may weigh 200 pounds or more.
A garage door with aging springs puts an enormous load on a garage door opener, so another sign of failing springs is when you hear the electric door opener begin to strain as it attempts to lift the door. At this point, it is time to consider replacing the springs. Aging door springs can also break suddenly, a situation that can cause the door to slam shut violently.
If you happen to be present when a spring breaks, you will hear a very loud sound like a gunshot, because the break usually occurs when the spring is fully loaded—stretched or twisted to its full tension. When one spring breaks, the door will suddenly feel very heavy when you try to open it by hand, and an automatic garage door opener may no longer be able to lift the door at all.
Garage door springs cannot be repaired. Maintenance involves the full replacement of both springs at the same time. If one spring has broken, it is a sure bet the other is nearing the end of its effective life.
If you have a garage door opener and you suspect that a door spring has broken, do not disconnect the opener from the door (by pulling the red emergency release handle) while the door is open. If you do, the door can come crashing down under its nearly full weight, with nothing to stop it. This is an extremely dangerous situation. It is never safe to leave the door open when a spring has broken because someone might try to close the door without realizing how heavy it is. Or, they might pull the emergency release handle on the opener.
If you need to leave the door open until you can make repairs, block the door track on both sides so the door can't move, and unplug the garage door opener (if you have one). If you want to close the door, you can try closing it with the opener, making sure there's nothing in the door's path in case something goes wrong. However, this will put some strain on the opener. Alternatively, you can have a few strong helpers hold the door while you disconnect it from the opener and carefully close the door manually—again, it will be very heavy.
When to Call a Pro
It's often recommended that garage door springs should always be replaced by pros. This is understandable advice, but the rule is not hard-and-fast. A moderately experienced homeowner who's competent with tools and has a basic understanding of mechanical systems can replace either type of garage door spring, thereby saving $200 to $300 in labor costs (on average).
The procedures are pretty basic, but they involve many steps that must be done in the proper order, just like the pros do it. It's also critical that you get the proper size replacement spring. If you think you're up to the task, look at online tutorials by garage door pros to see what's involved. Helpful videos explain how to measure your old springs and order the correct replacement size as well as how to do the job from start to finish.
Professionals can replace garage door springs in an hour or two. When you hire a pro, make sure to ask about the quality of the springs they will install. They may well offer several grades of springs to choose from, at a range of costs. Top-of-the-line springs may be guaranteed for life, while economy springs can be expected to last perhaps five years under normal use.
Because your automatic garage door opener has been under some strain as the springs have become more worn and less effective, this is also a good time to evaluate the opener. The same technician who replaces the springs can also replace the opener if it is nearing the end of its life.