Garage Door Glossary
Every part of a residential garage door and opener, defined in plain language: what it is, where it sits, and what it does. Use it to follow a quote, read a guide, or describe a problem on the phone.
Written by the ClearTech Garage Doors team in Winnipeg and checked against manufacturer documentation. Updated .
A
- Auto-reverse
- The opener safety function that stops and reverses a closing door when it meets resistance. Every opener sold since 1993 has it, and it is tested by closing the door onto a 2x4 laid flat on the floor; the door must reverse on contact. A tune-up checks it every time (Annual Tune-Up).
B
- Backroom
- The distance from the inside face of the door opening straight back into the garage along the ceiling. The horizontal tracks and the opener rail live in this space, so a new door needs roughly the door height plus 18 inches of backroom, and more when an opener is added. One of the five measurements in how to measure for a garage door.
- Balancealso: door balance
- The state of a door whose springs carry almost all of its weight. A balanced door, disconnected from the opener, stays where you leave it at waist height and lifts with one hand. A door that drops or drifts is out of balance, which overworks the opener; the balance test takes two minutes.
- Battery backup
- A rechargeable battery inside or beside the opener motor unit that runs the door for a limited number of cycles when the power is out. Without one, the door is opened by hand with the emergency release (opening the door in a power outage).
- Belt drive
- An opener that moves the trolley along the rail with a steel-reinforced rubber belt instead of a chain. It is the quiet choice for a garage under a bedroom; the belt needs no lubrication (choosing an opener).
- Bottom bracketalso: bottom fixture
- The steel bracket bolted to each bottom corner of the door where the lift cable attaches. It is under full spring tension whenever the door is closed, which is why it is usually marked with a warning tag: removing or loosening it can release that tension in an instant.
- Bottom sealalso: astragal, bottom weatherstrip
- The rubber or vinyl strip along the bottom edge of the door that presses against the floor to keep out drafts, water, snow, and mice. Most steel doors hold it in an aluminum retainer; the seal slides in from the end of the section (replacing a bottom seal).
C
- Cable drumalso: drum
- The grooved spool at each end of the torsion shaft that winds the lift cable as the springs turn the shaft. The two drums must be set identically or the door climbs crooked. A cable that has jumped its grooves is one of the most common repair calls (cable off the drum).
- Centre bearing bracketalso: spring anchor bracket
- The steel bracket bolted to the header at the middle of the door that supports the torsion shaft and anchors the stationary cones of the springs. On a two-spring door the springs sit on either side of it.
- Chain drive
- An opener that moves the trolley with a roller chain running along the rail, like a bicycle chain. It is the longest-serving opener design: strong and inexpensive, but noisier than a belt, and the chain needs occasional lubrication and tension checks.
- Conealso: winding cone, stationary cone
- The cast fitting at each end of a torsion spring. The stationary cone bolts to the centre bearing bracket; the winding cone at the other end has set screws that clamp it to the shaft and four holes for winding bars. Winding cones hold the spring's full tension and are the reason spring work is left to a technician (Spring Repair).
- Cycle
- One full open and close of the door. Springs are rated in cycles rather than years: a standard residential torsion spring is rated for about 10,000 cycles, which is seven to twelve years at typical use, and high-cycle springs are available (signs of a broken spring).
D
- DASMA
- The Door & Access Systems Manufacturers Association, the North American industry body whose technical data sheets set the conventions for door installation, spring replacement, safety testing, and maintenance that this site's guides are checked against.
- Direct drive
- An opener design in which the motor itself travels along the rail on a stationary chain, instead of a fixed motor pulling a trolley. There is one moving part, so it runs very quietly; Sommer is the best known maker (choosing an opener).
E
- Emergency releasealso: red cord, manual release
- The red-handled cord hanging from the opener trolley. Pulling it disconnects the door from the opener so the door can be moved by hand, for a power outage or a stuck opener. Pull it only with the door fully closed: if a spring is broken, a released door that is open can come down under its own weight (power outage guide).
- End bearing plate
- The flat steel plate at each end of the torsion shaft, bolted to the jamb or the flag bracket, that holds the bearing the shaft turns in. The cable drum sits just inside it.
- Extension spring
- A long coil spring mounted alongside each horizontal track that stretches as the door closes and contracts to help lift it. Common on older and single-car doors; every extension spring should have a safety cable through it, because a broken one can fly across the garage (torsion vs extension springs).
- EZ-Set
- Clopay's torsion spring system, wound with a power drill through a geared winder mounted on each end bracket rather than with winding bars. It looks like a standard torsion setup with a small gearbox at each end (EZ-Set explained).
F
- Flag bracket
- The tall angle bracket at the top of each vertical track where the curved track begins and the end bearing plate mounts. Its name comes from its shape, a vertical leg with a short horizontal flag.
- Force settingsalso: sensitivity
- Opener adjustments that set how much resistance the door may meet before the opener stops or reverses. Set too high, the opener will push through an obstruction instead of reversing; set too low, it reverses on a stiff hinge. They are not a cure for a door that is out of balance.
H
- Header
- The horizontal framing member across the top of the door opening. The centre bearing bracket, the opener's header bracket, and the top weatherstripping all mount to it, so it needs to be solid wood, not drywall.
- Headroom
- The clear space between the top of the door opening and the ceiling or the lowest obstruction above it. A standard torsion spring setup needs about 12 inches; low-headroom hardware works down to roughly 5 inches (how to measure).
- High-lift track
- A track layout in which the door travels farther straight up before curving back, used in garages with tall ceilings or a car lift. It needs special drums and usually a jackshaft opener, since a standard rail cannot reach.
- Hinge
- The stamped steel hinges that join the door's sections so it can bend around the curved track. Hinges are numbered by position (a 1 at the bottom joint, higher numbers up the door) and the end hinges also carry the rollers. Squeaks start here, and a drop of lubricant fixes most of them (lubricating a garage door).
- Horizontal track
- The section of track that runs back along the ceiling, hung from angle iron, that the door rests on when open. See track.
I
- Insulation (R-value)also: R-value, insulated door
- R-value is the measure of a door section's resistance to heat flow; higher is warmer. Polyurethane foam injected between two steel skins gives the highest R-value per inch, polystyrene panels less. The number applies to the section, not the whole door with its gaps (insulation and R-value).
J
- Jackshaft openeralso: wall-mount opener, side-mount opener
- An opener mounted on the wall beside the door that turns the torsion shaft directly, with no rail across the ceiling. It frees the ceiling, works with high-lift tracks, and is the usual choice when the garage has a car lift or storage overhead (choosing an opener).
- Jamb
- The vertical framing on each side of the door opening. The vertical tracks bolt to the jambs through the track brackets, and the perimeter weatherstripping nails to their outside face.
K
- Keypadalso: wireless keypad, entry pad
- The outdoor code pad mounted beside the door that opens it with a PIN, paired to the opener with the learn button. It runs on its own battery; a keypad that lights but no longer opens the door usually needs that battery first (opener guides).
L
- Lift cablealso: cable
- The braided steel cable on each side of the door that runs from the bottom bracket up to the cable drum. The springs do the lifting; the cables carry that lift to the door. Fraying, kinks, or rust at the bottom end mean it is close to snapping (Cable & Roller Repair).
- Lock modealso: vacation mode
- A setting on many wall consoles that disables every remote and keypad until it is switched off again, so the door can only be opened from the wall button. A remote that suddenly stops working while the wall button still works is often this (opener guides).
- Low-headroom track
- A hardware kit with a second, lower set of tracks and modified top brackets that lets a door operate where there is less than the standard 12 inches of headroom. Usually paired with a rear-mounted torsion spring.
M
- Motor unitalso: motor head, powerhead, the opener
- The box hung from the ceiling at the back end of the rail that holds the opener's motor, logic board, light, and the learn button. It moves the door; it does not carry the door's weight. That is the springs' job, which is why a door with a broken spring cannot be opened by a healthy opener.
O
- Openeralso: garage door operator
- The motorized unit that opens and closes the door on command: the motor unit, the rail, the trolley, and the safety sensors, together. Residential openers are rated by horsepower or newtons of force, and the right size depends on door weight and balance, not door size alone (Opener Repair & Installation).
P
- Panel vs. sectionalso: section, panel
- A section is one of the horizontal slabs, usually four or five, that make up a sectional door and hinge together. A panel is the embossed rectangle pressed into the face of a section for looks. In the trade, "panel replacement" means replacing a whole section.
- Photo eyesalso: safety sensors, safety beams
- The pair of small sensors mounted on the tracks about 6 inches off the floor that send an invisible beam across the opening. If anything breaks the beam while the door is closing, the opener reverses. Misaligned or dirty eyes are the most common reason a door refuses to close and the opener light blinks (opener guides).
- Pulley
- On an extension spring door, the grooved wheel at the end of each spring and at the front of each horizontal track that the lift cable runs around. Worn pulleys squeal and chew cables.
R
- Rail
- The straight steel or aluminum beam running from the motor unit to the header bracket above the door, which the trolley travels along. The chain, belt, or screw that drives the trolley runs inside or along it.
- Retaineralso: bottom retainer, seal channel
- The aluminum channel along the bottom edge of a steel door section with slots that grip the bottom seal. Retainers come in a few slot shapes (T, bead, bulb), so a replacement seal has to match the retainer, not just the door width.
- Roller
- The small wheel on a steel stem that sits in a hinge or bracket at the edge of each section and rides inside the track. Plastic rollers are the builder-grade default, steel rollers with open bearings are loud, and nylon rollers with sealed bearings are the quiet upgrade (garage door rollers).
- Rolling code
- Remote-control security in which the code sent to the opener changes on every press, so a recorded signal cannot be replayed. Every major opener brand has used it since the late 1990s under names like Security+ and Intellicode, and it is why a remote must be paired at the opener rather than copied.
S
- Safety cablealso: containment cable
- A steel cable threaded through the centre of an extension spring and anchored at both ends, so that when the spring breaks the pieces stay put instead of being thrown across the garage. DASMA treats it as required on every extension spring door.
- Sandwich constructionalso: steel-foam-steel, triple-layer door
- A door section built as an outer steel skin, a solid foam core, and an inner steel skin bonded together. It is stiffer, quieter, and warmer than a single-skin section with a foam board clipped behind it, and it is how most insulated doors sold in Winnipeg are made (insulation and R-value).
- Sideroom
- The wall space on each side of the door opening, from the edge of the opening to the nearest wall or obstruction, where the vertical tracks and the spring end hardware mount. Standard torsion hardware needs about 4 inches a side; some spring systems need more (how to measure).
- Strutalso: reinforcement strut
- A horizontal steel brace bolted across the inside of a door section to stiffen it. Wide doors carry one on several sections, and the top section should always have one where the opener arm attaches, or the section bows and eventually cracks at the arm.
T
- Threshold seal
- A raised rubber strip glued to the garage floor directly under the closed door, used when the floor is uneven or slopes toward the garage and the bottom seal alone cannot keep meltwater out (Weather Seal Replacement).
- Top bracketalso: top fixture, top roller bracket
- The adjustable roller bracket at each top corner of the door. Sliding it in or out sets how firmly the top section presses against the header weatherstripping when the door is closed.
- TorqueMaster
- Wayne Dalton's spring system, in which the torsion springs sit inside a steel tube above the door instead of on an exposed shaft. It is wound through a drive on the end bracket and has a small turn counter; parts and service differ from a standard torsion setup (TorqueMaster explained).
- Torsion shaftalso: torsion tube, shaft
- The steel shaft running across the full width of the door just above the opening, carried by the end bearing plates and the centre bearing bracket. The torsion springs wrap around it and the cable drums are clamped to its ends, so when the springs unwind, the shaft turns the drums and the cables lift the door.
- Torsion spring
- The tightly coiled spring mounted on the torsion shaft above the door that stores energy by twisting and releases it to lift the door. Double-car doors usually have two; a broken one shows a clear gap in the coil. It holds enough force to cause serious injury, so winding and replacement are a technician's job (signs of a broken spring, torsion vs extension).
- Track
- The steel channels the rollers ride in: a vertical track up each side of the opening, a curved radius section at the top, and a horizontal track back along the ceiling. Residential track is 2 inches wide; 3-inch track is used on heavy commercial doors. A door that has "come off the track" has rollers outside this channel (off-track doors).
- Travel limitsalso: limit settings, up and down limits
- The opener settings that tell it where fully open and fully closed are. A door that reverses just before it touches the floor, or stops short of fully open, usually has a limit set wrong rather than a mechanical fault.
- Trolleyalso: carriage
- The sliding part that rides along the opener rail and connects to the door through the curved door arm. The emergency release cord hangs from it; pulling the cord unhooks the trolley from the drive so the door moves freely. A trolley that moves while the door stays put has usually been released, or its drive has stripped.
U
- UL 325
- The North American safety standard for garage door openers. Since 1993 it has required every residential opener to reverse on contact and to have a secondary entrapment device, which in practice means photo eyes. Openers without working photo eyes do not meet it.
V
- Vertical track
- The length of track bolted to each jamb that guides the door's rollers straight up from the floor to the curve. It is where ice, gravel, and road salt collect in winter, and where a bent lip lets a roller pop out. See track.
W
- Weatherstrippingalso: stop moulding, perimeter seal, door stop
- The vinyl strip nailed to the outside of the jambs and header with a soft flap that presses against the face of the closed door, sealing the gap around the sides and top. It is separate from the bottom seal and is the usual fix for drafts and light showing around the door (weatherstripping guide).
- Winding bars
- The pair of solid steel rods, usually 18 inches long and sized to the holes in the winding cone, used to wind and unwind torsion springs. Screwdrivers and rebar are not substitutes; a bar that slips out of a loaded cone is how most spring injuries happen.
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