If you're in the process of replacing the extension or torsion springs, then you'll probably need to know exactly how much your garage door weighs in order to purchase the right springs. Pre-fabricated garage doors may have this information readily available, but custom doors are often a different matter.

This guide can help you figure out how much your garage door weighs in a safe and accurate manner.

Analog Scales Are a Must

The first thing you'll need for this task is a reliable analog scale. You can use an ordinary bathroom scale for this task, although it's preferable to use a floor scale or shipping scale if you happen to have one on hand.

There's a pretty good reason why you'll need an analog scale, as opposed to one that offers digital readouts. Most analog scales are designed to register weight changes as they occur. A digital scale, on the other hand, registers weight changes within a narrow amount of time, preventing you from seeing weight fluctuations in real time.

Making Preparations

Next, you'll need to prepare the garage door itself for the task at hand. Disconnect power from the garage door opener, either by unplugging the opener from its power outlet or shutting off power at the circuit breaker.

Use the emergency release handle on your garage door opener to disconnect the opener from the actual door. Afterwards, disconnect the opener arm from the garage door itself, so that it doesn't catch on the inner carriage.

You'll also need to locate and loosen the garage door cable so that the full weight of the door can be read accurately. Locate the bottom-most track bracket and clamp the cable to the bracket with a pair of vise grips or a C-clamp. You may need to repeat this step on the other side of the garage door.

Weighing Wooden Garage Doors

At this point, you'll need to open your garage door in order to place the scale underneath. That can be a difficult task in of itself, given how the garage door opener is no longer supporting the door's full weight. You need to use a pry bar and an assortment of short and long 2x4 lumber pieces in order to leverage the door open:

• Start by wedging the end of your pry bar underneath the door. Use a small 2x4 to leverage the door to slide another, longer piece of 2x4 underneath the door. Make sure the 2x4 is slid in perpendicular, not parallel, to the door opening.
• With the longer 2x4 in place, slid a smaller 2x4 underneath the larger 2x4 and raise the door further.
• Slide the scale underneath the door, making sure to position the scale so that it's not only in the center of the door, but also with the readout visible from inside the garage.
• Carefully lower the garage door onto the scale and record your measurements.

Weighing Steel Garage Doors

Steel garage doors are a bit easier to damage, so you'll need to take the following steps to prevent the door from being bent while leveraging it open:

• Go to one of the corners of your garage door and place your pry bar underneath the bottom fixture.
• Place a small 2x4 underneath the pry bar and use it to leverage the door open. Place another 2x4 underneath the door to hold it open.
• Wedge your pry bar underneath the door where it's resting on the 2x4. You'll need to leverage the door open again so that another 2x4 can fit on top of the first 2x4. In the end, you'll need two boards on top of one another underneath the door.
• Place a long 2x4 directly underneath and parallel to the garage door. Use the pry bar to leverage both the door and the board upwards. Slide another 2x4 underneath the door, making sure it sits perpendicular to the garage door.
• Remove the pry bar and use the perpendicular 2x4 to lift the door further, and then slide the scale underneath the door. Carefully lower the door onto the scale and record the readings.

When you're finished, simply reverse the above steps. In some cases, you may need to place a 2x4 on top of the scale just to make sure the door sits level as you weigh it. Just make sure to subtract the weight of the 2x4 from your final readings. 

For more information, or for help with this and other garage door services and repairs, contact a local garage installation and repair company, or visit sites like http://www.garagedoorjax.com/.