There are two types of garage door springs.  Expansion (extension) and torsion. All springs are under tremendous pressure and are considered dangerous.  Only professionals should work on these springs.

Torsion Springs

Broken Garage Door Spring First I will talk about the torsion springs and how we inspect them.  Torsion springs come in many different sizes.  They twist to help support the door to make it easier to open and close. Each one is designed to support certain weights and sizes of overhead garage doors.  The first thing we have to do is determine if the springs are the correct size for the door they are helping to lift.  If the springs are professionally installed, the installer will spray paint a line straight across the springs.  The springs are supposed to be wound 7.5 times.  So we should see 7.5 spaces between the lines if the springs are properly wound. Then we disconnect the door from the garage door opener.  We move the door so that the bottom of the door is close the the middle of the opening.  The door should stay in the middle, fully open, and the fully closed position.  If the door falls or springs up, there is a problem.  

Expansion Springs

Expansion springs are a bit different.  They stretch to help support the door open and close.  Their proper length and size will be unknown to home inspectors.  They should be the same on both sides.  The door should stay in the fully closed and open position without any help.  Springs are ordered for the size of the door.  Extension spring sizes use two numbers.  The first number is the length of the spring when the spring is NOT extended.  The second number is half the height of the garage door. So an Extension spring sized 25″X42″: would mean the not extended length is 25″ and the height of the door would be 7 feet.  42″ x 2 = 84″ or 7 feet

They are also color coded at the ends.  The codes are as follows.

  • White 10, 110, 210 lbs
  • Green 20, 120, 220 lbs
  • Yellow 30, 130,230 lbs
  • Blue 40, 140, 240 lbs
  • Red 50, 150, 250 lbs
  • Brown 60, 160,260 lbs
  • Orange 70,170, 270 lbs
  • Gold 80, 180, 280 lbs
  • Light Blue 90, 190, 290 lbs
  • Tan 100, 200, 300 lbs Door Heights – 

The most important thing to check when inspecting these doors is that a safety cable is installed.  These springs break.  When they break, they are violent.  The cable secured at both ends will keep the spring from damaging property or harming people and animals should they be near when it does break.  We will also check that both springs are the same on both sides.  This includes length and color coding.  And when we open the door; it should open equally on both sides.