Garage Door Glossary: Terms Explained in Plain English
Springs, drums, tracks, photo-eyes, R-value, and more, explained by people who work on doors every day on the Grand Strand.
When a technician starts talking about drums, astragals, and headers, it helps to know what they mean. This glossary covers the terms you’re most likely to hear, in everyday language, so you can understand your door and feel confident asking questions. It’s written by people who work on doors every day on the Grand Strand, and we’ve linked to detailed guides where relevant.
Category
Door Parts
- Panel (section)
- One of the horizontal segments that make up the door. Most doors have four or five stacked panels. See panel replacement.
- Hinge
- The metal joint connecting two panels so the door can bend as it goes around the curve of the track. See hinge and bracket repair.
- Track
- The metal rails on each side of the door that guide it up and down. See track repair.
- Roller
- The small wheel, usually nylon or steel, that rides inside the track. See roller replacement.
- Bracket
- A metal fitting that holds hardware in place. The bottom brackets, where cables attach, are under high tension and should never be loosened by a homeowner.
- Astragal (bottom seal)
- The rubber or vinyl seal along the bottom edge of the door. See weatherstripping replacement.
- Threshold seal
- A seal attached to the garage floor that adds a second barrier against water and pests.
- Stile
- The vertical piece at the edge of a panel that provides structure and hardware mounting points.
- Header
- The structural framing above the door opening.
- Jamb
- The vertical framing on each side of the door opening.
Category
Spring System
- Torsion spring
- A spring mounted horizontally on a shaft above the door that twists to counterbalance the door’s weight. See torsion vs. extension springs.
- Extension spring
- A spring that runs along the side tracks and stretches and contracts as the door moves.
- Safety cable
- A cable that runs through an extension spring to contain it if it breaks.
- Cable
- The steel wire that connects the bottom of the door to the drum or spring system. See cable repair.
- Drum
- The grooved wheel at each end of a torsion shaft that winds and unwinds the cable.
- Shaft
- The metal bar that torsion springs mount on.
- Winding bars
- The specialized tools used to safely wind a torsion spring. Never improvise these.
- Cycle
- One complete open and close of the door. Spring life is often rated in cycles. Standard springs are commonly rated around 10,000 cycles.
- High-cycle spring
- A spring built to last more cycles than a standard spring.
- Balance
- How evenly the springs offset the door’s weight. A balanced door stays in place when lifted halfway by hand.
Category
Opener Terms
- Opener (operator)
- The motorized unit that raises and lowers the door. See opener repair.
- Trolley
- The part that slides along the rail and connects to the door.
- Rail
- The track the trolley slides along, attached to the opener.
- Belt drive / chain drive / screw drive
- The three common ways an opener moves the trolley. Belt drives are typically quietest.
- Horsepower (HP)
- A rating of opener motor power, matched to door weight.
- Logic board
- The circuit board that controls the opener. Moisture damage is a common problem on the coast.
- Emergency release
- The red cord that disconnects the door from the opener for manual operation.
- Photo-eye (safety sensor)
- The pair of sensors near the floor that detect obstructions. See our sensor guide.
- Auto-reverse
- The feature that reverses the door if it meets resistance.
- Remote / keypad
- Wireless controls for the opener. See programming.
- Smart opener
- An opener with WiFi connectivity and app control. See smart openers.
- Battery backup
- A battery that keeps the opener working during a power outage.
Category
Materials and Performance
- Steel
- A common door material, available in various gauges.
- R-value
- A measure of insulation performance. Higher means better insulation. See insulated vs. non-insulated.
- Polystyrene / polyurethane
- Two common types of foam insulation in doors.
- Wind load
- The pressure wind puts on a door. Wind-rated doors are built and tested for higher loads. See wind-rated doors.
- Galvanized
- Steel coated with zinc to resist rust.
- Carriage-house style
- A door designed to look like traditional swing-out barn doors while operating as an overhead door.
Category
Coastal and Storm Terms
- Corrosion
- Deterioration of metal from chemical reaction, accelerated by salt and moisture. See our coastal corrosion guide.
- Salt air
- Airborne salt particles from the ocean that speed up rust.
- Hurricane season
- June 1 through November 30 in the Atlantic. See the hurricane checklist.
- Windborne debris
- Objects carried by high wind that can dent or damage a door.
Category
Service Terms
- Off-track
- A door whose rollers have left the track. See off-track repair.
- Tune-up
- A maintenance visit with inspection, lubrication, and adjustment. See maintenance.
- Itemized invoice
- A bill that lists each part and labor charge separately. We provide one every time.
Frequently Asked Questions
Springs store the energy that counterbalances the door; cables connect the door to that system.
It’s a measure of insulation. A higher R-value means better resistance to heat flow.
A pair of safety sensors near the floor that stop the door from closing if something’s in the way.
One full open and close. Spring lifespans are often rated in cycles.
Call (854) 248-1833 and we’ll explain it in plain terms.