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 100 terms

A5 terms

A-Frame Vertical Lift

An A-frame vertical lift bracket holds the spring and shaft so a commercial door travels straight up with no overhead track. Learn when it is specified and how it differs from standard lift.

Air Infiltration

Air infiltration measures how much outdoor air leaks through a closed garage door. Learn how it is tested and which components affect your door's infiltration rate.

Aladdin Connect

Aladdin Connect is Genie's Wi-Fi retrofit that adds smartphone control to an existing Genie opener. Learn how it installs, what it does, and how it compares to Chamberlain myQ.

Anodize

Anodizing grows a hard oxide layer on aluminum garage door parts for corrosion resistance and color. Learn how the process works and why it matters for frames, tracks, and hardware.

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.

B3 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 Rail

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

C12 terms

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 cable breaks. Learn how it works, where it mounts, and when it is required on commercial doors.

Cable Stop

A cable stop is a swaged fitting that anchors a lifting cable in the drum slot. Learn how swaging works, where the stop sits on the drum, and what happens when one fails.

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 anchors the torsion spring assembly at mid-span above the garage door opening. Learn what attaches to it and how it differs from end bearing plates.

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 reinforcement at the mid-point of a garage door section. Learn how it works with center hinges, end stiles, and struts to keep sections rigid.

Chain Hoist

A chain hoist is a hand-operated sprocket for raising heavy commercial rolling doors without a motor. Learn how it works and when it is used on industrial doors.

Counterbalance System

The counterbalance system is the spring, cable, and drum assembly that offsets garage door weight. Learn the components, how torsion and extension systems differ, and what fails.

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 metal section in a rolling door curtain. Learn how slats interlock, what profiles exist, and how they connect to the hood and windlocks.

Cycle

A cycle is one complete open-and-close operation of a garage door. Learn how cycle ratings determine spring and component life expectancy in residential and commercial use.

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 on a torsion spring clamped by cone hardware. They do not add torque. Learn how to identify them when counting active coils for spring sizing.

Dock Leveler

A dock leveler bridges the gap between a warehouse floor and a truck bed, enabling safe forklift access. Learn the types, how each works, and what to look for when specifying one.

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 panel, or carriage house. Learn how styles differ and how to choose.

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 and provides hinge attachment points. Learn about end stiles and center stiles.

Double Low Headroom Track

Double low headroom track uses two parallel overhead tracks to open a garage door with very limited clearance above the header. Learn when it is needed and how it works.

Duplex Spring

A duplex spring nests two torsion springs on one shaft, doubling lift capacity without extra shaft space. Learn when duplex springs are used and how they are wound.

E5 terms

Embossment

Embossment is the stamped surface texture pressed into garage door steel skins. Learn how wood-grain and panel embossments work, what they add, and how they relate to door style.

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. Learn how it differs from a center stile and what it connects to.

Entrapment Protection

Entrapment protection is the UL 325 safety requirement for garage door openers that prevents injury from a closing door. Learn which devices qualify and how they work.

Extension Spring

Extension springs stretch above horizontal tracks to store lift energy. Learn how they differ from torsion springs, what a sheave does, and when to replace them.

EZ-Set Spring System

The EZ-Set Spring System is Clopay's drill-powered torsion spring winding system that replaces manual winding bars. Learn how it works and which Clopay doors include it.

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 older garage door opener security system that uses matching physical toggle switches in the remote and receiver. Learn why rolling code replaced it.

Flag Bracket

A flag bracket is the L-shaped fitting that joins vertical and horizontal garage door track at the top corner. Learn how it fails and what track radius matching means.

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 solder device that releases a fire door to close when temperature reaches its rated threshold. Learn where it installs and NFPA 80 rules.

G2 terms

Galvanizing

Galvanizing is a zinc coating on steel garage door parts that blocks rust. Learn how G90 coating weight works and which parts on a door are typically galvanized.

Garage Door Remote

A garage door remote is a handheld transmitter that sends a coded radio signal to the opener receiver. Learn about rolling code vs. fixed code, frequency, and programming the learn button.

H3 terms

Header

The header is the horizontal beam spanning the top of a garage door opening. Learn what attaches to it, how to measure headroom from it, and how it differs from a lintel.

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.

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.

I2 terms

Insulated Glass

Insulated glass uses two or more sealed panes with a trapped air or gas gap to reduce heat transfer. Learn how it is used in garage door sections and what it adds to overall door R-value.

IPPT (Inch-Pounds Per Turn)

IPPT (inch-pounds per turn) is the torque a torsion spring delivers per revolution. Learn how technicians use IPPT to size a spring to match a specific door weight.

J2 terms

J-Arm

A J-arm connects the opener trolley to the top garage door section, transferring the trolley's motion to push and pull the door. Learn how it mounts, why it fails, and what to look for.

Jamb

A jamb is the vertical framing member on each side of a garage door opening. Learn how the track, flag bracket, and weatherstrip all attach to the jamb during installation.

L7 terms

Lift Clearance

Lift clearance is the gap between a garage door opening's top and the horizontal track centerline. Learn standard dimensions, how it relates to headroom, and when high-lift is needed.

Lifting Cable

A lifting cable connects the bottom of a garage door to its cable drum. When the spring unwinds, the drum winds the cable and the door rises. Learn specs and failure signs.

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. Learn how it differs from a header, what it carries, and why it matters for door installation.

Logic Board

A logic board is the circuit board inside a garage door opener that processes inputs from remotes and sensors to control door movement. Learn what it does and when it fails.

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 horizontal edge of a garage door section that mates with the rail on the section above or below it to form a weathertight joint between sections.

Muntin

A muntin is the grille bar that divides a garage door window into smaller panes. Learn the difference between true divided and decorative (faux) muntins and how they affect appearance.

N1 term

NFPA 80

NFPA 80 governs fire door installation and annual maintenance for rated assemblies including rolling steel doors. Learn what it covers and how it ties to building codes.

O3 terms

Opener Rail

An opener rail is the aluminum track the trolley travels on between the motor and the door header. Learn how rail length, drive type, and mounting height affect opener installation.

Opener Trolley

The opener trolley rides the opener rail and connects to the door via a J-arm to push and pull it open and closed. Learn how it works, what the emergency release does, and what fails first.

Opening Size

Opening size is the clear width and height of a garage door opening measured between jambs and from floor to header. Learn how it differs from door size and rough opening.

P2 terms

Pan Door

A pan door is an uninsulated commercial garage door made from formed sheet metal sections with no foam core. Learn where pan doors are used and how they compare to insulated commercial doors.

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.

R7 terms

Reverse Angle Mounting

Reverse angle mounting flips vertical track to reduce sideroom. Learn when it is needed, how it differs from standard mounting, and what bracket changes it requires.

Rolling Door Bottom Bar

A rolling door bottom bar is the steel member at the base of a rolling curtain. Learn what it carries, how it connects to sensing edges, and why it matters for fire and safety compliance.

A rolling door curtain is the interlocked steel slat assembly that opens by coiling around a barrel above the opening. Learn slat profiles, materials, and how the curtain connects to other components.

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 of a rolling steel door that retains the curtain edges and seals the sides of the opening during operation.

Rolling Door Hood

A rolling door hood is the sheet metal cover over a rolling door's barrel and coiled curtain. Learn hood sizing, mounting, and how it works with the barrel and guide assembly.

Rolling Grille Door

A rolling grille door coils like a solid rolling door but uses open mesh links for airflow and visibility. Learn where it is used, how it differs from solid curtain doors, and what to specify.

S11 terms

S-Hook

An S-hook connects an extension spring to the sheave bracket in a garage door cable system. Learn where S-hooks sit in the extension spring assembly and when to replace them.

Sandwich Construction

Sandwich construction is the three-layer design of insulated garage door sections: outer steel, foam insulation, and inner steel backer. Learn how it differs from single-skin doors.

Sheave

A sheave is a ball-bearing cable pulley used with extension springs to redirect the garage door lifting cable. Learn how it differs from a plain pulley, where it mounts, and when to replace it.

Shiplap Joint

A shiplap joint is the overlapping meeting-rail profile between garage door sections that sheds rain and blocks air infiltration. Learn how it differs from tongue-and-groove joints.

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, where the door rises vertically then curves into horizontal overhead tracks. Learn headroom requirements and when to use other lift types.

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 garage door jambs that the closed door presses against. Learn how it seals the perimeter, what materials are used, and when to replace it.

T12 terms

Tempered Glass

Tempered glass is heat-treated safety glass used in garage door windows that shatters into small blunt pieces rather than sharp shards. Learn why codes require it.

Tension Wheel

A tension wheel adjusts the counterbalance spring tension on a commercial rolling steel door. Learn how to set it and why correct tension prevents motor strain and runaway descent.

Thermal Bowing

Thermal bowing warps insulated garage door sections when inner and outer steel skins are at different temperatures. Learn why it happens and how manufacturers limit it.

Thermal Break

A thermal break is the non-metal strip between a door section's steel skins that stops heat from bypassing the foam core. Learn why it matters for R-value accuracy.

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 the top corners of a garage door's top section that holds the guide roller. Learn how it differs from standard edge hinges.

Top Rail

The top rail is the horizontal frame member at the top edge of a garage door section. Learn how it differs from meeting rails and what attaches to it on the top section.

TorqueMaster

TorqueMaster is Wayne Dalton's enclosed torsion spring system housed inside a steel tube. Learn how it differs from standard torsion springs, what breaks, and what replacement involves.

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 rises from vertical to horizontal travel. Learn how it affects driveway and opener clearance.

V1 term

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.

W4 terms

Wall Console

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

Winding Cone

A winding cone is the end fitting on a torsion spring that accepts winding bars. Learn how it differs from the stationary cone and why tensioning it is high-risk.

Windlock

A windlock keeps a rolling door curtain locked in its guides under wind pressure. Learn how windlocks work with guides, what wind ratings they enable, and where they are installed.

Wireless Keypad

A wireless keypad opens a garage door by PIN code without a remote. Learn how keypads pair to openers, how to set a temporary guest PIN, and how rolling code keeps them secure.

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