If you want to replace your garage door springs on your own, you need to buy a new set of springs. Below we explain how to purchase so-called extension springs. Typically, springs of this type can be seen on smaller doors (8′ or 9′). Unlike torsion springs, they run alongside and above the tracks.
Before you actually start looking for the replacement springs, you need to measure the width and the height or your door, as well as the length of the old springs. Also, you need to get the weight of the door.
Measure the size of your garage door and the length of the springs
This step is pretty simple. Write down the width and height of your door, measured with a tape measure. Keep in mind that it should be a nominal size.
Measuring the spring can be successful only when the spring is relaxed or the door is up. If one of the springs is broken (and that is very likely if you are going to replace them), you may measure the pieces separately and add the numbers.
How to find out the weight of the garage door
If you cannot find the weight of your door on its ID Tag, we recommend looking for it online. Before you start, check out the name of the manufacturer, model number, and style. With this information in hand, you have a chance for a successful search.
In case both the methods mentioned above did not bear fruit, you will face a fairly difficult task of actually weighing the door.
To start with, put two 2″ x 4″ boards on a regular analog bathroom scale. We do not recommend using digital scale as it only registers weight in a narrow window of time. Analog scales are capable of showing how the weight changes.
Position the scale under the corner of the garage door on the same side as the broken spring (in case one of the springs is broken). Now you know how much ½ of the door weighs. Multiply by two to have the final result.
Are both the springs broken? In this case, you will have to position the scale in the center of the door. Asking for help sounds like a good idea as without springs a garage door is extraordinary hard to lift, taking into consideration its weight may exceed 350 LBS.
Some Internet sources provide calculators that help to determine the door weight judging from the material it is made of. However it is nothing but an approximate figure and it is not reliable enough for purchasing the springs.
Purchasing Garage Door Springs
Now you are ready to order a new kit of springs. You may get one in your favorite home supply store or find it online. Choose the springs that best suit the actual weight of your door.