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 123 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

What the Genie adapter adds to an opener you already own, what it costs, the one Wi-Fi band it will not join, and where to start when setup stalls.

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 Lear's built-in garage door button in many Chrysler, Jeep, Dodge and RAM vehicles. How to program it, and how it compares with HomeLink.

Center Bearing Plate

The center bearing plate holds the torsion shaft above the middle of the door and anchors both springs. Why it must bolt into solid wood or steel framing.

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 springs, cables and drums that offset a garage door's weight. How the counterbalance works, how a balanced door behaves, and signs it is failing.

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 is the garage door makers' trade group. What its TDS data sheets cover, what "meets DASMA" means for cycle life and wind load, and who relies on it.

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 garage door frame is the jambs and header that finish the opening. What bolts to it, how wide the jambs need to be, and how block garages get one.

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 garage door section is one horizontal panel of a sectional door. Typical heights, how many a 7- or 8-foot door uses, and when one can be replaced.

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)

DIP switches are the small toggles in older garage door remotes and openers that set a fixed code. How they pair, why they are easy to copy, what replaced them.

Flag Bracket

The flag bracket joins the vertical and horizontal garage door track at the top corner. What it connects, signs it is loose, and why the radius must match.

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

Cape Cod and vaulted garages cannot take level horizontal track. How the pitch is measured and ordered, and why a standard trolley opener often won't fit.

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

Garage door hinges join the sections and carry the rollers. What hinge numbers mean, why the wrong number binds the door, and signs a hinge is worn.

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 steel bar bolted across a door section so it does not bow from wind or opener force. Where struts go and signs you need one.

H7 terms

Header

The beam above your garage door carries more than the door. What mounts to it, the lumber a 16-foot opening needs, and the headroom a standard lift takes.

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 track runs the door higher before it turns overhead, freeing ceiling space and clearance for tall vehicles. What it needs and where it fits.

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 the Gentex garage door button in many car visors and mirrors. How it works, how to program it, and why it needs re-pairing after a new opener.

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 pairs a garage door opener with a new remote or keypad. Where to find it, how pairing works, and how holding it erases old remotes.

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

Garage door lift cables run from the bottom brackets to the drums and raise the door as the spring unwinds. Sizes, strength, and the fraying signs to watch.

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

The opener circuit board reads remotes, the wall button and safety sensors and runs the motor. Signs a logic board has failed and how to match a replacement.

Low Headroom

How much clearance a standard track needs, how little you can get away with on a low-headroom kit, and the opener that fits when the ceiling is too tight.

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

Motor runs, door does not move: the trolley is the usual reason. What it connects to, how the emergency release frees it, and the two parts that wear out.

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 walk-through door built into a sectional or rolling overhead door. How it is framed, where it is used, and why it is not a legal exit.

Perimeter Seal

The weatherstripping along the top and sides of a garage door. What a perimeter seal blocks, signs it has worn out, and how it pairs with the bottom seal.

Photo Eye Sensor

Garage door photo eyes send an infrared beam across the opening and reverse the door when it breaks. Where they mount, what the lights mean, common faults.

R9 terms

R-Value

Most insulated garage doors rate R-6 to R-18. What R-value measures, why polyurethane foam beats polystyrene, and when a higher number pays off at home.

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

The three brand names rolling code hides behind, what makes a remote and opener drift apart, and the reset that pairs them again when HomeLink refuses.

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 the ball-bearing pulley that turns the lifting cable on an extension-spring garage door. How it works, how it wears and why the groove matters.

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

Spring bumpers are the cushioned stops in the horizontal track that catch the door at full open. How they work and how moving one changes where it stops.

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.

T13 terms

Telescoping vertical lift

Telescoping vertical lift is a door whose leaves rise and nest behind each other, so a tall opening needs far less headroom than standard vertical lift.

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 is the steel rod the springs turn to lift a garage door. Solid vs. hollow shafts, what mounts on one, and the signs a shaft is bent.

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

Garage door track radius is the curve where the track turns overhead. When 12-inch, 15-inch and low-headroom track fit, and how the radius sets headroom.

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

The features an opener must have to meet UL 325, the model year that splits compliant openers from the rest, and what the standard added after that.

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

Garage door vertical track: the steel channel on each jamb that guides the rollers up. How it mounts, why it must be plumb, and signs it is out of line.

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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