A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 


Angle Mounted Track - A method of fastening vertical track to a doorjamb using a full height continuous angle. 


Back Hangs-The vertical supports for the horizontal track, cross-braced to prevent lateral movement and track spread.

Backroom -The required clearance from the face of the header to any obstruction to the rear of the horizontal track.

Bead metal, vinyl or rubber strip used to secure glass around the periphery of a pane. 

Bottom Bracket structural support located on the bottom section of the garage door that provides for attachment of the lifting cables on the sectional garage doors. Also referred to as "Bottom Corner Bracket." 

Bracket Mounted -Track method of fastening vertical track to a doorjamb using angle brackets. Also referred to as "Mounted or Track Bracket."

Break-Away -Track Vertical track assembly that steps back from the jamb used for high lift and vertical lift track to permit outside lock handle projection to clear the lintel. 

Bumpers, Spring leaf spring installed at the end of the horizontal track. Especially useful on lift clearance or full vertical manually operated garage doors, acting as a cushion and stop. 


Cable Drums Grooved drums on the torsion spring shaft that lifting cables wind around when the garage door opens. Designed to allow cable to be accumulated or dispensed in an orderly manner and to prevent lapping or cable chafing.

Cable Safety Device safety bottom fixture specifically designed to prevent a garage door from falling if a cable breaks.

Cable Sleeve manufactured device used to form a loop of cable, the size of which is determined by the cable diameter.

Cable Stop swagged fitting at the end of the cable to prevent slippage through a slot in a drum.

Cables Multistrand wire used to attach the garage door, via bottom brackets, to the counterbalance mechanism.

Center Bearing Plate See "Center Support Bearing."

Center Hinge Flat hinge located on all intermediate stiles to allow for garage door sections to turn the track radius as the door opens.

Center Lift Cable Additional cable assembly, which is secured to the outside of the garage door at points toward the center of the door. Used to provide extra lifting support for extremely wide or heavy doors. 

Center Stile/Multi Vertical members of a garage door section that provide structural rigidity and location for center hinge attachment. 

Center Support Bearing Bearing and mounting plate installed at approximately half the door width above the garage door, which acts as a support for the spring shaft. Can be mounted in various locations, not necessarily in the center, depending on size of the springs.

Clearances The amount of sideroom, headroom, and backroom required to properly install a sectional garage door.

Coupling Adjustable two-part cast iron connector for torsion solid shafts on wide garage doors. Eases installation and allows adjustment in cable lengths so that doors will operate smoothly without cocking.

CurtainThe part of the sheet door that actually rolls up and down or slides side to side. Manufactured of corrugated sheets seamed together.

Cycle One complete cycle of begins with the garage door in the closed position. The door is then opened and closed again. Note: Torsion spring operated garage doors with higher-than-normal cycle life requirements may be specified with 25,000, 50,000, or 100,000 cycle springs.


Dead Load static-applied load. A load without movement.

Door FrameThe frame into which the garage door fits, consisting of a door header and two upright members called doorjambs.

Double-Thick GlassLighter than plate glass, about 1/8" (3.18 mm) thick, often termed double-strength glass. 

Drums Circular stamped metal parts attached at various locations along the tubular shaft that allows the sheet door curtain to coil up when the garage door opens.

Duplex Spring combination of two torsion springs.


End Stiles Stile located at each end of a garage door section that provides for attachment of end hinges.

Escutcheon plate surrounding the lock mechanism that acts as a bearing surface for the lock shaft; one of the parts of a lock set, usually held in place by small screws known as escutcheon screws.

Exhaust Ports Orifices put in the bottom section of a garage door for release of carbon monoxide fumes when tubed from an automobile exhaust system. 

Extension SpringsCounterbalance springs that provide lifting force by stretching. Commonly called stretch springs. Extension springs are mounted to each of the rear track hangers and attached to a pulley at the other end of the spring.

Exterior Lock Keyed lock that can be operated on exterior of the garage door. Extrusion Fabricated aluminum or plastic shapes made by forcing hot aluminum or plastic billets through an extrusion press die.


Flag Bracket-shaped bracket used to facilitate the union between vertical and horizontal tracks.

Flush Design Refers to garage door sections unbroken by roll-formed ribs. The face of the complete garage door presents an even surface.

Follow-the-Roof Track Designed to place the back track on the roof incline, and as close as practical to the roof. Can be used with standard lift or lift clearance track. 

Front-Mounted Low Headroom Low headroom hardware where springs mount on torsion shaft above opening. 

Full Vertical Track Assembly An assembly designed from a piece of vertical track and a piece of continuous angle or jamb brackets. Used to secure the track to the jamb. 

Full Vision Section totally glazed section with various types of glass or clear plastic. The section is formed of aluminum extrusions that combine with steel sections above and below. 


Galvanizing Zinc coating to protect steel against corrosion.

Glass, Insulated Two pieces of glass spaced approximately 1/4" (12.7 mm) apart and hermetically sealed to form a single-glazed unit with an air space between. Heat transmission through this type of glass can be as low as half that of non-insulated glass.

Glass, Tempered Reheated to just below the melting point and suddenly cooled. When shattered it breaks into small pieces. 

Glass, Wire Polished or rough glass, 1/4" (6.35 mm) thick. Wire mesh is embedded within the glass so that the glass will not shatter when broken. Many types of wire patterns are available. 


Headplate Structural bracket used to secure vertical and horizontal track, as well as counterbalance systems.

Headroom measurement from the top of the garage door opening upward to the lowest building obstruction on the inside of the header wall. Use this measurement for vertical clearance all the way back to the end of the horizontal track.

High Cycle Springs Special counterbalance springs with increased life cycle capability for high usage garage doors.

Hinges To make the independent sections to act as a complete garage door, the sections must be hinged together. 
Hinges are found on the end stiles and center stiles at the meeting rails. All hinges perform two basic functions within a garage door system: 1. They join the sections together with bolts or screws. 2. They allow the sections to break, independent of each other, as the garage door travels up and down.

Hinges on the end stiles perform two additional tasks: 1. They are designed to support the roller on which the the garage door travels. 2. They are offset to provide a flush fit to the garage door itself when in the closed position.

Horizontal Track An assembly usually made up of a section of track and reinforced with an angle that is used to both guide and support the garage door in the horizontal position. Furnished with an integral section of curved track. 


Incline To slope, to slant. To follow roof pitch. 

Inclined TrackTapered vertical track and a graduated height of edge hinges that assure a weathertight fit between the garage door and jamb.

Inside LockSpring loaded, sliding deadbolt lock operable only from the interior of the garage door.InsulationMaterial that has the ability to reduce heat or cold transmission.

Insulation Terms:BTU Amount of heat necessary to raise the temperature of one pound of water, one degree Fahrenheit.

K-value (Thermal Conductivity) Laboratory-determined value of the thermal conductance of a material.

R-value (Thermal Resistance) Ability of a material to retard the transmission of heat. The higher the R-value, the better the garage door insulation performance.

U-Factor (Heat Transmission Coefficient) Amount of heat, in BTU, transmitted through one square foot of material (the garage door) in one hour at a temperature difference of 1° Fahrenheit from one side to the other. The lower the U-value, the better the insulating material.


Jamb Seal Weather-stripping attached to the garage door jamb to provide a seal along the jambs.

JambsThe upright framing on each side of the garage door opening. When wood jambs are specified, the vertical track is mounted to the inside surface of the jamb and the stop molding is nailed to the side surface within the opening. 


Lift ClearanceRefers to track hardware that causes the garage door to rise vertically some distance before leveling out into a horizontal position. Also known as "High Lift Track," Lift-Clearance is the distance above the top of the garage door opening to the underside of horizontal tracks.

Lift-Handle handle, normally on the bottom section of the garage door, to assist in manually lifting the sectional door. Lites Frames glazed with glass or clear plastic. The number of panels in a section limits the quantity of lites that can be installed. May be double glazed for insulation value. 

Low Headroom Track hardware accessories to improve garage door installation with minimum headroom conditions.


Master Keying Arrangements whereby cylinder locks, although fitted with different keyed cylinders, can be opened or locked by one master key. In new buildings, the hardware supplier has responsibility for the lock cylinder and the locking device has to be coordinated with the hardware supplier. Cylinder may be furnished by this supplier and changed in the field.

Meeting Rail The top or bottom horizontal rail in any section that meets and joins with an adjacent garage door section in horizontal rail.

Mounting PlatesFlat steel or wood members placed on the wall to accommodate spring support, spring shaft bearings, chain hoists and mountings for operators.

Movable Center Post lightweight extruded aluminum post/track assembly, which substitutes for the jamb between two adjacent garage doors and can be released and carried from the opening.

Mullion slender dividing bar between two garage doors. Usually designed to carry horizontal (wind) load but not vertical load. 

Muntin bar member supporting and separating panes of glass within a sash or door.


NEMANational Electrical Manufacturers Association. Established to provide standards for electrical components. Number designation refers to motor operator and controls to meet the ambient requirements.


Opening SizeFrequently called daylight opening or finished opening. Dimensions are taken between masonry or wood walls or between steel jambs.

Opening Width Distance between jambs of the garage door opening.

Outside Hook-upBottom fixture with an arm that bends around vertical track to receive lifting cables. Generally used with low headroom hardware. 


Padding Refers to the wood framing at jambs and header to which the garage door track is mounted. 

PaneThe area between vertical stiles in a garage door section.

Pass Door Sometimes called wicket door or access door. It is a small swing door built into the larger upward acting garage door allowing people to walk in and out without opening the large door. 

Pedestrian Door Access door adjacent to the upward acting garage doors. Avoids the use of a sectional door as a legal egress. 

Perimeter Seal Complete weather-stripping package for sectional garage doors, consisting of astragral, jamb seal and header seal.

Perimeter Wearstrip Vinyl or felt attached to corrugated sheet door curtain to prevent rubbing. Located at the ends or drum locations.

Pane the area between vertical stiles in a garage door section.

Pass Door

 Sometimes called wicket door or access door. It is a small swing door built into the larger upward acting garage door allowing people to walk in and out without opening the large door. 


Rabbeted JointJoint formed by connecting rails with grooves cut out in opposing edges to permit overlapping weathertight meeting of sections. 

RadiusThe curved portion of the track, which allows the door to move from vertical to horizontal. The curve is measured in inches, thus determining headroom requirements. 

Rain or Water Stop step at the edge of the garage floor, approximately 1" (25.4 mm) higher than the outside finish. The garage door sits between the two.

Rear Track Hangers Often constructed of punched angle iron, laterally braced, these hangers attach the end of the horizontal track to the garage ceiling. 

Removable Post Designed to allow the use of two or more garage doors in a single opening with center posts that can be removed when doors are raised. Especially desirable where small openings are required normally, but occasionally the entire clear opening is necessary. 

Reverse Angle Mounting exceptionally sturdy method of track mounting used on all steel jambs and wood jambs at the architect's direction. 

Roller AssemblyThe combination of a wheel and axle that is used to guide a garage door through the track system, either 2" (50.8 mm) or 3" (76.2 mm) diameter, depending on track size. 

RollersSteel, ball-bearing wheels or nylon rolelrs that allow sections to roll freely along garage door tracks.

RSLO/LSLORight side looking out/left side looking out. Used to indicate hand of chain hoist or electric operation or lite or exhaust port location. 


Safety Spring Containment An extra cable used with garage door extension springs to prevent it from causing damage or injury if the spring breaks. The cable is threaded through the center of the spring and is secured on both ends of the horizontal track.

Sectional Joint Meeting Rail Seal An integral weather-strip with the section at the joints between garage door sections.

Sectional Garage Doors Garage doors made of two or more horizontal sections hinged together to provide a door large enough to close the entire opening. Sectional doors are guided into the horizontal or open position by a system of vertical or horizontal tracks. May be fabricated of continuous roll-formed steel with reinforcing ribs or flush sections of steel or aluminum.

Shaft BearingsType of bearing that adequately supports the radial forces dictated by the weight of the counterbalance assembly and door weight, and the lateral forces exerted. See "Center Support Bearing."

Shafts, Tubular and Solid tubular or solid steel counterbalance shaft transmits the lifting force of the torsion springs to the cable drums and lifting cables.

Sheave pulley with integral ball bearings designed to handle a cable. Used to control the movements of the cables employed in the garage door counterbalance system. Various types are stud or clevis.

Shiplap Joint The configuration of the meeting rails. When closed, the shiplap prevents rain, wind, and light from infiltrating the garage door between the door sections. 

Sideroom horizontal measurement from each side of the garage door opening outward along the wall to the nearest obstruction within the building.

Spring Anchor PlatesDesigned to transmit torque from the stationary end of a torsion spring to the building structure and, at the same time, support the weight of the torsion shaft in a level attitude. The anchor plate is able to withstand the lateral forces exerted by a torsion spring. Usually supplied by the general contractor.

Spring Assembly Hardware used to make up the garage door counterbalance assembly.Spring Bumper Small spring-cushioning bumper attached to the horizontal track, which stops the door at the full open position.

Spring FittingsThe sleeves or cones that are used to affix the torsion springs to the torsion shaft. One piece is a stationary sleeve or spring retainer, and the second piece is an adjusting cone or winding sleeve.

Steel Jamb MountingContinuous angle attached to vertical track and fastened to the jamb by welding, self-tappers, or bolts. 

Steel Jambs Door framing made from either channel or angle iron.

Stop Molding Seals the perimeter of the garage door against weather and light infiltration. Stop molding is nailed to the jamb, outside the door, and is incorporated as one of the final steps in the installation process. Sometimes called doorstop, it is usually wooden or plastic.

Stop Bars or brackets mounted at the top of guides to prevent bottom bar from traveling out of the guides when the sheet door curtain is fully raised. 

Straight Incline Track Vertical track assembly that extends from floor to twice the height of the opening without break-away feature. 

Struts-shaped metal reinforcement members attached horizontally to the inside of the garage door section to add strength and rigidity. Struts are necessary on wide heavy garage doors to help prevent sagging and bowing and to provide additional reinforcement to comply with the required windloading. Also called trusses.



 Provides a guide for the roller wheels. The vertical track is mounted to the jambs with brackets on each side of the garage door opening. The horizontal track contains a curved end called the radius .In the closed position, the garage doors rest in the vertical track. In the open position, the garage doors suspend from the horizontal track. Sectional door track usually consists of two vertical pieces and two horizontal pieces.

Tongue-and-Groove The configuration of the meeting rails that differs from shiplap in having matching channel groove and protrusion on the longitudinal edges of the abutting meeting rails for wind and weather protection.

Top Fixture Adjustable brackets that carry track rollers mounted on the top corners of the garage door's top section.

Top Header Seal Flat weatherstrip fastened along the full width of top door section as a seal along the header.

Top Rail The horizontal rail forming the top horizontal member of a garage door as distinguished from the meeting rails and bottom rail.

Top Seal Weatherstripping that fastens to the top of the garage door generatoing a seal along the top of the opening.

Torque The turning effect of a tangential force acting at a distance from the axis of rotation or twist; torsion springs apply such effect to spring shafts.

Torsion Shaft The shaft of a torsion spring assembly that transmits the lifting force of the torsion springs to cable drums and lifting cables.

Torsion Spring Counterbalance Assembly Designed and constructed to provide a safe and durable conversion of spring torque to lifting force by balancing the weight of a sectional overhead garage door.

Torsion Springs Mounts above the garage door opening. The springs are manually wound, or charged, then set to a shaft that runs through the spring. The spring turns the shaft, which raises or lowers the door via the cables winding on drums.

Track Provides a guide for the roller wheels. The vertical track is mounted to the jambs with brackets on each side of the garage door opening. The horizontal track contains a curved end called the radius .In the closed position, the garage doors rest in the vertical track. In the open position, the garage doors suspend from the horizontal track. Sectional door track usually consists of two vertical pieces and two horizontal pieces.

Trajectory The arc of travel, or sweep of the top section, as the garage door is raised from closed to open position. Determining the trajectory is important when planning the location of pipes, light fixtures, etc.


Vertical Lift hardware design that allows a sectional garage door to open vertically along the wall above the door opening without turning back inside the building. 


Wicket Door Hollow-metal pedestrian door installed adjacent to the sheet door that shares the same building opening.

Winding BarsUsed by garage door installers to set initial tension on torsion springs at the winding cones.

Winding Cone Part that fits into a torsion spring, permitting winding of the torsion spring and tension adjustment.

Winding Sleeves Designed to safely allow the application of torque from a torsion spring. The winding sleeves' design properly retains a torsion spring when fully wound or unwound and withstands the radial and lateral forces exerted by the torsion spring.

Windload The lateral force that the wind exerts upon a garage door as it stands in a closed position.

Wood Jamb Mounted  

Wood Jambs Upright wooden piece forming the side of the garage door opening

Weatherstripping that fastens to the top of the garage door generatoing a seal along the top of the opening.

TorqueThe turning effect of a tangential force acting at a distance from the axis of rotation or twist; torsion springs apply such effect to spring shafts

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