Because garage door springs and openers can degrade over time, it’s important to occasionally test this safety feature. With the garage door open, place a solid object such as a 2-by-4 board or a cinder block where the door will close. Never test any safety feature using your or another person’s body. With the board or block in place, press the close button. If working properly, the garage door should close on the obstruction and immediately reverse the closing operation when it comes in contact with it.
Step 2: Check the tracks with a level to make sure they're properly aligned. Horizontal tracks should slant slightly down toward the back of the garage; with roll-up doors, the vertical sections of track should be exactly plumb. Both tracks must be at the same height on the garage walls. If the tracks are not properly aligned, loosen but do not remove the screws or bolts that hold the mounting brackets, and tap the tracks carefully into position. Recheck the tracks with the level to make sure they're in the right position; then tighten the screws or bolts at the mounting brackets.
Fiberglass and vinyl garage doors are composite units, combining a steel core behind a fiberglass or vinyl skin. They have also polyurethane insulated base sections, or other type of foam insulation. These premium doors can match steel garage doors, and be a realistic imitation of wood (namely fiberglass units), but they may be more expensive than steel units.