Glossary

Garage Door Glossary

Plain-English definitions of the parts, hardware, openers, and industry terms behind every garage door. Tap any term for the full explanation.

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Showing 122 terms

A5 terms

A-Frame Vertical Lift

An A-frame vertical lift bracket supports the torsion spring and shaft so a commercial garage door rises straight up without overhead track curves.

Air Infiltration

Air infiltration rates how much outdoor air leaks through a closed garage door, measured to ASHRAE standards and influenced by seals and weatherstripping.

Aladdin Connect

Aladdin Connect is Genie's plug-in Wi-Fi adapter that retrofits smartphone control and real-time status monitoring to compatible Genie garage door openers.

Anodize

Anodizing is an electrochemical process that grows a protective oxide layer on aluminum garage door parts, making them resistant to corrosion and surface wear.

Astragal

An astragal is the rubber or vinyl weatherstrip on a garage door's bottom rail that seals against the floor. Learn how astragals work and when to replace them.

B4 terms

Back Hang

A back hang is a steel bracket that suspends the horizontal garage door track from the ceiling. Learn where back hangs install and what happens when they fail.

Barrel Assembly

A barrel assembly is the horizontal cylinder above a rolling steel door that holds counterbalance springs and coils the curtain. Learn its key parts and role.

Bottom Bracket

The bottom bracket is the steel fitting at each lower corner of a garage door that anchors the lift cable and attaches to the bottom section's end stile.

Bottom Rail

The bottom rail is the horizontal steel frame at the base of the lowest garage door section that holds the astragal seal and anchors the lift cable bracket.

C13 terms

Cable Drum

A cable drum is the grooved spool at each end of a torsion shaft that winds the lifting cable as the spring unwinds, pulling the garage door upward.

Cable Ferrule

A cable ferrule is a metal sleeve crimped onto a lift cable end to form a loop or stop. Learn how it terminates a garage door cable and what failure looks like.

Cable Safety Device

A cable safety device stops a garage door from free-falling when a lift cable breaks, typically required on commercial high-cycle doors over a certain weight.

Cable Stop

A cable stop is a swaged metal fitting crimped onto the end of a lifting cable that seats in the drum slot to anchor the cable as the drum winds.

Car2U

Car2U is a Lear in-vehicle system for programming factory car buttons to open your garage door. Learn which vehicles include it and how it compares to HomeLink.

Center Bearing Plate

The center bearing plate mounts above the garage door opening to support the torsion shaft at mid-span and anchor the spring assembly between two springs.

Center Hinge

A center hinge is a flat steel hinge on the center stile of a garage door that lets adjacent sections pivot. Learn how center hinges differ from edge hinges.

Center Stile

A center stile is the vertical steel reinforcement at the mid-point of a garage door section that resists racking and provides the hinge attachment point.

Chain Hoist

A chain hoist is a hand-operated sprocket mechanism for raising commercial rolling doors without a motor, used in locations without reliable power supply.

Counterbalance System

The counterbalance system is the spring, cable, and drum assembly that offsets garage door weight so the opener or a person can lift it with minimal effort.

Counterweight System

A counterweight system balances a heavy door using hanging weights on cables instead of springs. Learn where they are used and how they compare to springs.

Curtain Slat

A curtain slat is one interlocking formed-metal section in a rolling door curtain that hooks to adjacent slats, collectively making up the coiling door curtain.

Cycle

A cycle is one complete open-and-close operation of a garage door, used to rate the expected life of springs, openers, and other hardware components.

D10 terms

DASMA

DASMA sets garage door industry standards through its TDS series. Learn what DASMA publishes, how TDS numbers are organized, and why compliance matters.

Dead Coils

Dead coils are the inert end coils of a torsion spring clamped by cone hardware that add no torque and must be excluded when counting active coils.

Dock Leveler

A dock leveler bridges the height gap between a warehouse floor and a truck bed, enabling safe forklift and pallet-jack access during loading and unloading.

Dock Seal

A dock seal creates a weathertight barrier between a loading dock door opening and a truck trailer. Learn how dock seals work and their main components.

Door Frame

A door frame is the jambs and header that form the finished border of a garage door opening. Learn what attaches to it and how frame size affects door fit.

Door Panel Style

Door panel style describes the decorative design on each garage door section—flush, raised panel, recessed, or carriage-house—defining the door's appearance.

Door Section

A door section is one horizontal panel of a sectional garage door. Learn how sections connect, what they are made of, and how many a typical door has.

Door Stile

A door stile is the vertical structural member inside a garage door section that resists racking under load and provides hinge and roller attachment points.

Double Low Headroom Track

Double low headroom track uses two overhead rails to open a garage door when clearance above the header is too limited for standard track configuration.

Duplex Spring

A duplex spring nests two torsion springs on a single shaft to double lift capacity without extending shaft length, used on heavier or wider residential doors.

E7 terms

Embossment

Embossment is the stamped texture pressed into garage door steel skins to create wood-grain and decorative panel patterns without additional paint or material.

End Bearing Plate

The end bearing plate mounts on the left and right walls above a garage door to support the torsion shaft ends and position the cable drums at each side.

End Stile

An end stile is the vertical member at each end of a garage door section that carries the edge hinges and corner rollers connecting the section to the track.

Entrapment Protection

Entrapment protection is the UL 325 requirement that garage door openers include devices to detect and stop on any obstruction before it can trap a person.

Extension Spring

Extension springs mount above horizontal tracks on each side of a door and stretch open to store lift energy, counterbalancing door weight on lighter doors.

Extension Spring Safety Cable

An extension spring safety cable threads through a stretched extension spring and contains it if it snaps, preventing the broken coil from becoming a hazard.

EZ-Set Spring System

The EZ-Set Spring System is Clopay's drill-powered torsion spring that replaces manual winding bars, making spring changes safer without traditional tools.

F6 terms

Faux Divided Lite

A faux divided lite uses surface grille bars to make a single garage door window look like multiple small panes. Learn how it differs from true divided lites.

Fixed Code (DIP Switch)

A fixed-code DIP switch is the bank of toggle switches in older garage door remotes and receivers where matching physical positions form the shared access code.

Flag Bracket

A flag bracket is the L-shaped fitting at the top of each jamb that connects vertical and horizontal garage door track at the top corner of the track run.

Flush Design

Flush design is a garage door style with a flat, panel-free exterior surface. Learn how it differs from raised-panel doors and where it is most commonly used.

Follow-the-Roof Track

Follow-the-roof track angles garage door track to match a sloped ceiling. Learn when to use it, how pitch angles work, and what opener types pair with it.

Fusible Link

A fusible link is a heat-activated device that releases a fire-rated door to close automatically when temperatures reach the code-specified threshold.

G4 terms

Galvanizing

Galvanizing is the zinc coating applied to garage door steel parts to block rust, measured as a coating weight such as G90 (0.90 oz of zinc per sq ft).

Garage Door Hinge

A garage door hinge is the stamped steel plate that joins adjacent sections of a sectional door, letting them pivot as the door moves through the curved track.

Garage Door Remote

A garage door remote is a handheld radio transmitter that sends a coded signal to the opener receiver to open or close the door from inside a vehicle or nearby.

Garage Door Strut

A garage door strut is the horizontal steel reinforcement bar that spans a door section to prevent it from bowing under wind load or opener thrust.

H7 terms

Header

The header is the horizontal beam spanning the top of a garage door opening where flag brackets, track hardware, and the opener rail mount during installation.

Headroom

Headroom is the clear vertical space between the top of a garage door opening and the lowest ceiling obstruction, which determines what track system fits.

High-Lift Track

High-lift is a track configuration that adds extra vertical rise before the door transitions to horizontal travel, freeing overhead space for tall vehicles.

High-Performance Door

A high-performance door is a fast-cycling commercial door that opens at 100+ IPM, limiting energy loss at busy warehouse and production facility openings.

HomeLink

HomeLink is a built-in vehicle transmitter, found in sun visors and mirrors, that controls garage door openers and gates without a handheld remote.

Horizontal Radius

The horizontal radius is the curved track piece that transitions a garage door from vertical to horizontal. Learn how radius size affects headroom requirements.

Horizontal Track

The horizontal track guides garage door sections into the overhead ceiling-parallel position after they clear the curved transition section of the track.

I2 terms

Insulated Glass

Insulated glass uses two or more panes separated by a sealed gas gap to reduce heat transfer, used in garage door window sections to improve door R-value.

IPPT (Inch-Pounds Per Turn)

IPPT (inch-pounds per turn) measures the torque a torsion spring delivers per revolution, used to match a replacement spring to the door's exact weight.

J3 terms

J-Arm

A J-arm is the steel bracket connecting the opener trolley to the door's top section, transferring the trolley's linear motion to push and pull the door.

Jamb

A jamb is the vertical framing member on each side of a garage door opening where the vertical track, flag bracket, and side weatherstripping mount and seal.

Jamb Seal

A jamb seal is the flexible weatherstrip along each side jamb that compresses against the closed door's edge to block wind, rain, and debris from entering.

L8 terms

Learn Button

The learn button is a recessed button on a garage door opener that pairs the opener to a new remote or keypad by accepting the transmitter's radio signal.

Lift Clearance

Lift clearance is the vertical gap between the top of a garage door opening and the horizontal track centerline, setting the baseline for standard or high-lift.

Lifting Cable

A lifting cable is the steel wire connecting the garage door's base to its cable drum; as the spring unwinds, the drum winds the cable and raises the door.

Limit Switch

A limit switch tells a garage door opener when the door has reached open or closed and stops the motor. Learn how limit switches work and how to adjust them.

Lintel

A lintel is the structural steel or concrete beam spanning a masonry garage door opening that carries the wall load and supports the door frame above.

Logic Board

A logic board is the circuit board inside a garage door opener that processes remote signals and sensor inputs to control motor direction and travel limits.

Low Headroom

Low headroom is when clearance above the garage door opening is too tight for standard track. Learn what hardware solves the problem and what the limits are.

Low-E Glazing

Low-E glazing is glass with a thin metallic coating that blocks infrared heat while passing visible light. Learn how it improves garage door window performance.

M2 terms

Meeting Rail

A meeting rail is the shaped horizontal edge of a garage door section that interlocks with the adjacent section above or below to form a weathertight joint.

Muntin

A muntin is the bar dividing a garage door window into smaller panes, available as true divided glass or as a decorative grille overlay over a single pane.

N1 term

NFPA 80

NFPA 80 is the U.S. fire protection standard governing installation, testing, and annual inspection of fire-rated door assemblies including rolling steel doors.

O5 terms

Opener Battery Backup

An opener battery backup is a secondary power source built into compatible garage door openers that allows the door to operate during a power outage.

Opener Force Setting

The opener force setting controls the motor torque a garage door opener applies before stopping, preventing the door from closing on an obstruction.

Opener Rail

An opener rail is the aluminum channel mounted between the motor unit and the door header that the trolley travels along to drive the door open and closed.

Opener Trolley

The opener trolley is the carriage that rides the opener rail and connects to the door via a J-arm to push and pull it open and closed during powered operation.

Opening Size

Opening size is the clear width and height of a garage door opening, measured between jambs and from floor to header, which is smaller than the door itself.

P4 terms

Pan Door

A pan door is an uninsulated commercial garage door made from formed sheet steel sections without a foam core, used where thermal performance is not required.

Pass Door

A pass door is a swing door built into a large garage or rolling steel door for foot traffic. Learn where pass doors are used and their code requirements.

Perimeter Seal

A perimeter seal is the complete weatherstripping system around a garage door's top and side edges that closes gaps between the door frame and door panels.

Photo Eye Sensor

A photo-eye sensor is a pair of infrared devices mounted near the floor on each side of a garage door that reverses closing if the beam is broken.

R9 terms

R-Value

R-value measures the thermal resistance of insulated garage door sections—higher numbers mean less heat transfer through the door's foam and steel layers.

Reverse Angle Mounting

Reverse angle mounting orients the vertical track's flange inward to reduce the sideroom required at each jamb when standard clearance is not available.

Rolling Code

Rolling code is a security protocol that generates a new encrypted signal each press of a remote, preventing code-grabbing attacks on garage door openers.

Rolling Door Bottom Bar

The rolling door bottom bar is the steel member at a rolling curtain's base that seals the opening, supports sensing edges, and carries safety hardware.

Rolling Door Curtain

A rolling door curtain is the coiling interlocked steel slat assembly that opens by winding around a barrel overhead, used on commercial rolling steel doors.

Rolling Door Governor

A rolling door governor controls curtain descent speed on a fire-rated rolling steel door. Learn how the governor works and why fire doors must have one.

Rolling Door Guide

A rolling door guide is the vertical channel on each jamb that retains the curtain edges and blocks air and debris from entering along the sides of the opening.

Rolling Door Hood

The rolling door hood is the sheet metal enclosure over a rolling door's barrel and coiled curtain, protecting the assembly from weather and damage.

Rolling Grille Door

A rolling grille door is an open-mesh coiling door that provides airflow and visibility through an opening while still acting as a physical security barrier.

S12 terms

S-Hook

An S-hook is an S-shaped wire link connecting an extension spring's stationary end to the sheave bracket on a garage door, completing the cable assembly.

Sandwich Construction

Sandwich construction is the three-layer design of insulated garage door sections: outer steel skin, bonded foam core, and an inner steel or vinyl backer.

Sensing Edge

A sensing edge is a pressure-sensitive strip on a commercial garage door's bottom bar that reverses the door when it contacts a person or object during closing.

Sheave

A sheave is a grooved ball-bearing cable pulley used in extension spring systems to redirect the lifting cable toward the door's bottom corner bracket.

Shiplap Joint

A shiplap joint is the overlapping edge profile between garage door sections where one meeting rail's lip covers the other to shed water and block air.

Smoke Gasketing

Smoke gasketing seals a fire-rated rolling steel door's perimeter to limit smoke passage per NFPA 105. Learn where it installs and what standard requires it.

Soft Start / Soft Stop

Soft start / soft stop is a garage door opener feature that ramps speed up and down at each end of travel. Learn how it reduces noise and extends opener life.

Spring Bumper

A spring bumper is a cushioned stop on the horizontal track that absorbs impact when the garage door reaches full open. Learn where it mounts and what it does.

Spring Cycle Life

Spring cycle life is the open-close cycles a garage door spring is rated to survive. Standard is 10,000 cycles; high-cycle springs reach 100,000 or more.

Standard Lift

Standard lift is the most common garage door track configuration: the door rises vertically then curves into horizontal overhead tracks parallel to the ceiling.

Stationary Cone

A stationary cone anchors the non-rotating end of a torsion spring to the center bearing plate. Learn how it pairs with the winding cone to tension the spring.

Stop Molding

Stop molding is the trim nailed to each garage door jamb that the door's edge compresses against when closed, providing a seal and a positive stopping point.

T12 terms

Tempered Glass

Tempered glass is heat-treated safety glass required in garage door windows; it fractures into small blunt granules on impact instead of sharp shards.

Tension Wheel

A tension wheel is the adjustment mechanism on a commercial rolling door used to set spring counterbalance tension so the curtain weight is properly balanced.

Thermal Bowing

Thermal bowing warps insulated garage door sections when the outer steel skin heats in sun while the inner skin stays cool, causing the section to curve.

Thermal Break

A thermal break is a non-metal separator between a door section's inner and outer steel skins that prevents heat from conducting around the foam core.

Tongue-and-Groove Joint

A tongue-and-groove joint interlocks garage door sections for a tighter weather seal. See how it compares to shiplap and why the profile matters for insulation.

Top Fixture

A top fixture is the adjustable bracket at each top corner of a garage door that holds the guide roller and leads the top section into the curved track.

Top Rail

The top rail is the horizontal steel member at the top edge of a garage door section that provides rigidity and connects to hinges and the top fixture bracket.

TorqueMaster

TorqueMaster is Wayne Dalton's enclosed torsion spring system with the coil sealed in a steel tube, requiring proprietary parts for service or replacement.

Torsion Shaft

The torsion shaft transmits spring torque to cable drums to lift a garage door. Learn its specs, what attaches to it, and signs it has bent or failed.

Torsion Spring

A torsion spring mounts above the garage door on a shaft and counterbalances door weight by twisting. Learn key specs and what components it connects to.

Track Radius

Track radius is the measurement in inches of the curve where garage door track bends from vertical to horizontal. Learn how it affects headroom requirements.

Trajectory

Trajectory is the arc the top garage door section sweeps in front of the opening as it transitions from vertical rise to horizontal travel overhead.

U1 term

UL 325

UL 325 is the UL safety standard requiring garage door openers to include entrapment protection such as photo-eye sensors and force-limiting controls.

V3 terms

Vertical Lift

Vertical lift keeps garage door sections on the wall instead of going overhead. Learn when it is used, how springs differ, and what wall height it needs.

Vertical Track

The vertical track is the section of garage door track mounted along each jamb that guides door sections straight up from the floor to the horizontal curve.

Vision Lite

A vision lite is a framed glass or polycarbonate insert in a commercial garage door section that admits daylight and provides sightlines into the bay.

W4 terms

Wall Console

A wall console is the hardwired push-button panel inside the garage that operates the opener, controls the light, and activates the opener's lock function.

Winding Cone

A winding cone is the end fitting on a torsion spring designed to accept winding bars, allowing a technician to add tension to the spring during service.

Windlock

A windlock is a steel bracket that locks a rolling door curtain in its guide channels under wind pressure, preventing the curtain from deflecting out.

Wireless Keypad

A wireless keypad opens a garage door by PIN entry without a remote, paired to the opener via the learn button and supporting temporary guest access codes.

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