Residential - Commercial - Industrial


Know Your Garage Door, Durham Region ON

Know Your Garage Door System – Garage Door Terminology Explained

How well do you know your garage door system?

Did you know, on average, a garage door opens and shuts 1500 times each year?

That on average a garage door is raised and lowered approximately 4-6 times a day?

That it’s actually the torsion spring which does the heavy lifting of a garage door, and not the opener?

Or how about this sobering fact? If a garage door or operator system is improperly installed or adjusted, it can exert a formidable amount of force when the door closes, and subsequently could cause injury, entrapment, damage or worse.

Most of us don’t put much thought into the mechanics and individual parts that make it possible for the garage door to open and close at our bidding. However, we might find ourselves suddenly interested in knowing a little more about the door system if it stopped working and needed to be repaired!

Get to Know Your Garage Door

Watch this brief video from for an overview of the different parts of the garage door (i.e. cables, sensors, rollers, etc.) and how each part functions within the system.

To increase your knowledge of garage door systems and understand the terminology a repair technician is using, refer to this glossary where we’ve compiled a comprehensive (though not complete) list of terms and definitions relating to garage doors, installation and service. If you need a repair or tune up, contact us today!

While not impossible for a skilled do-it-yourself-er to replace parts on their own, we STRONGLY recommend that you hire a knowledgeable, trained professional to do repairs, especially when dealing with parts that are under extreme tension – such as torsion springs. Many people are seriously injured every year as a result of attempting repairs without proper training and equipment. It is ESSENTIAL to have the right tools and know-how to do the job safely. At Upright Door Service Inc., our technicians are highly qualified, and have the expertise to spot and correct potentially dangerous situations.

And once you know garage door and the terminology associated, learn 4 common reasons why your garage door may need service.

Discover the history of the garage door opener, today’s technology and the possibilities for the future by clicking here.

Know Your Garage Door - Garage Door Diagram_DurhamRegionON



Here is a comprehensive, though not complete, list of terms used when describing garage doors, installation and service.

Adjusting Cone (See “Winding Cone/Winding Sleeve)

Air Infiltration The leakage or passage of air through a door system.

Angle Brace Lateral brace attached to back hang and roof construction or ceiling.

Angle Iron Brackets Length of L-shaped steel material used to support and brace horizontal track from ceiling

Astragal See “Bottom Weather Seal” and “Weatherstrip”

Astragal Retainer A component, mounted to the bottom edge of a door, that holds an astragal (bottom weather seal) in place.

Back Hang Hanger fabricated from angle iron, which attaches the end of the horizontal tracks to roof construction or ceiling.

Backroom Horizontal distance measured into the building from the face of the header above a door opening to the first obstruction at the required headroom. Should be at least 18″ more than the height of the garage door.

Battery Backup Emergency system that allows operation of garage door system in the event of a power outage.

Belt Drive Garage door opener uses rubber belts to open door, eliminating the metal-on-metal contact that occurs in other drives, therefore offering smooth, quiet operation.

Bottom Bracket This structural support bracket located on the bottom garage door section, holds track rollers and may provide for the connection of lifting cables. WARNING: Never remove the screws from this bracket because the whole lifting system (spring / tube / drum / cable) is under very high tension.

Bottom Rail The lowest horizontal rail of a door section.

Bottom Weatherseal A compressible seal/weatherstrip attached to bottom rail of the garage door to provide a seal between the floor and garage door, and is intended to improve a door’s performance against air infiltration and thermal transmission.

Bow Condition where a garage door bottom rail of a wood door is not level or straight. Closed door’s corners appear to turn up or “smile”.

Cable Multi-strand galvanized wire rope used to attach the garage door, via bottom brackets, to the counterbalance mechanism.

Cable Drum Grooved drum, fitted on torsion spring shaft that lifting cables wind around as the garage door opens. WARNING: Do not loosen set screws as parts are under extreme tension.

Cable Length The specific amount of cable required to properly operate a garage door.

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

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

Carriage House Stamped Design  Garage doors shaped from steel and embossed with a wood grain finish replicates the historic look of carriage style doors that used to swing, slide or fold open.

C.H.I. Carriage House Stamped with 4 Pc Arched Stockton Windows
C.H.I. Carriage House Stamped with 4 Pc Arched Stockton Windows

Centre Bearing Bracket A plate or bracket that houses a shaft bearing and aligns and supports the torsion shaft and spring assembly. It also anchors stationary cone(s) to header. WARNING: Do not remove screws from this bracket as parts are under high tension.

Centre Bearing Plate A plate or bracket that houses a shaft bearing and aligns and supports the counterbalancing mechanism to the torsion shaft, as well as anchoring one end of torsion spring to header. WARNING: Do not remove screws as parts are under high tension.

Centre Hinge Flat hinge located on all intermediate stiles to allow for section break as door operates. Also used as graduated edge hinge between bottom and intermediate section.

Centre Stile Vertical member of door section providing structural rigidity and location for centre hinge attachment.

Chain Drive Oldest style and perhaps among most common of garage door openers. Uses a chain attached to metal trolley to open the garage door.

Chain Hoist A sprocket or pocket wheel that is connected to the torsion spring shaft to provide mechanical advantage to raise and lower a manually-operated garage door by use of a hand chain.

Chain Hoist Operator Jackshaft type operator to which chain hoist is attached.

Clearance The amount of side room, head room and back room required to properly install a sectional door.

Commercial Door A sectional overhead garage door intended for vehicular use at entrances of buildings such as manufacturing plants, loading docks and service stations, and is normally operated less than 5,000 cycles per year.

Containment Cable A cable threaded through an extension spring to retain the spring if it breaks.

Counterbalance To oppose or balance with an equal weight or force.

Counterbalance System A system which counteracts the weight of a garage door to reduce human or motor effort required to operate the door.

Cycle One complete opening and closing operation of the garage door.

DASMA An international manufacturing trade association called Door and Access System Manufacturing Association. It contains 5 divisions including: residential & commercial sectional doors; rolling doors; operator & electronics; specialty; and association division.

Dead Load/Dead Weight A load without movement (a static applied load) generally referring to the weight of the door.

Decorative Hardware Accessories to decorate your garage door.

Door Frame The frame into which the door fits; consists of two upright door jambs, and a door header.

Door Header The upper part of a door frame, consisting of the head jamb, head casing, stop and trim molding.

Door Jamb The upright framing on each side of the door opening.

Door Movement There are 4 types of door movement: standard lift, full vertical lift, high lift and low headroom. The type of door movement to use is determined by the room available between the top of the door and the ceiling (or first obstruction).

Door Opener See “Garage Door Opener”

Door Opening (Daylight Opening) Opening dimensions taken between the floor and header and between face of door jambs.

Door Size Door dimensions specified by the width first and the height second.

Double Door Commonly used to refer to larger width doors used on two car openings.

Drum See “Cable Drum”

End Bearing Plate Plate commonly used on torsion spring counterbalance units, are used to secure the counterbalance spring assembly to the door track and to the wall. They include a ball bearing to support radial movement of a torsion shaft at each end. WARNING: Do not remove bolts as parts are under extreme tension.

End Stile Stile located at each end of a door section which provides for attachment of graduated edge hinges. They are responsible for carrying the total section load, and therefore must be of superior strength to provide structural integrity.

Extension Spring A garage door has one of two types of counterbalance spring systems – an extension spring system or torsion spring system. An extension spring is generally mounted above horizontal tracks, extends from front of door opening to the back hang and provides lifting power by stretching. WARNING: Springs are under extreme tension. We strongly recommend leaving any necessary repairs to trained professionals.

Exterior Lock Keyed lock on exterior of door.

Flag Brackets These L-shaped brackets connect the vertical and horizontal tracks and secure them to the jamb and header.

Flush Door Design The garage door face has an even surface and is not interrupted by visible rails and stiles.

CHI Flush Panel - Durham Region ON
CHI Flush Panel

Follow-the-Roof Pitch (Contour Track) Horizontal track that allows the garage door to follow the contour of roof construction or ceiling.

Full View Section Garage door section is completely glazed with various types of glass or clear plastic. Aluminum extrusions join with steel or aluminum sections above and below. This style offers bright light, open visibility and modern design – excellent for architectural applications such as fire-halls, restaurant patios, car dealerships, service stations, etc.

Garage Door Opener Electric motorized device to control door operation.

Gauge Unit of measure to evaluate the thickness of sheet metal. The smaller the gauge number, the thicker the steel.

Glazed Fitted with panes of glass or clear plastic.

Graduated End Hinge Hinges located on edge of door sections which allow sections to pivot as door opens and closes. They also support the track rollers that the garage door travels on, and are graduated and numbered (#1-#10)  for correct placement to provide a flush fit against the jamb when the door is closed.

Grille Insert within a window intended to enhance the window’s appearance and give appearance of divided lites.

Hang Down Refers to the amount of the garage door that hangs down from the opening when the door is in the open position.

Header Seal Weatherstripping mounted at opening header to seal the opening between header and curtain.

Headroom Vertical distance between the opening height of the door and the garage ceiling (or lowest ceiling obstruction) required for proper operation of the door and hardware. Minimum headroom required is 12″

High Lift A standard 7′ garage door has tracks that gently curve and then level into a horizontal position about 8′ off the garage floor. High Lift (or Lift Clearance) is the distance above the top of the garage door opening to the underside of the horizontal track when high lift track is required. High Lift garage doors have a longer portion of vertical track from the top roller and the curved portion of the track, which changes the trajectory of the door so it extends vertically before leveling into the horizontal position.

High Lift Track Track and hardware that causes the door to rise vertically some distance above the top of the door opening before it levels out into a horizontal position.

Hinge Garage doors are made up of independent sections –  hinges are located on end stiles and centre stiles at the meeting rails, and  are necessary to join the sections together so they operate as one complete door.  Hinges join the door sections together with bolts and screws, and allow the sections to “break” or pivot independent of each other as the door travels. (See “Graduated End Hinge” and “Centre Hinge”).

Garage Door Parts: Hinge, Durham Region ON

Horizontal Radius Section of track that transitions from vertical to horizontal track welded, bolted or riveted to the horizontal track and then bolted to the flag angle.

Horizontal Track Comprised of a section of track and reinforced with an angle to guide and support the garage door as it suspends in the horizontal position. The horizontal track contains a curved end called the radius (See “Radius”).

IDA International Door Association plays a key role in quality control in the door and access systems industry. It’s primary mission is to provide helpful programs and services to dealers, “to enhance their value and professionalism”. IDA partners with the Institute of Door Dealer Education and Accreditation to produce educational, certification and accreditation programs.  IDA members represent the highest quality door system professionals available to general public.


IDEA The Institute of Door Dealer Education and Accreditation (IDEA) is an educational organization established to meet the informational needs of consumers and the business and accreditation needs of door and operator dealers.

Inside Lock Spring loaded, sliding deadbolt lock or spring latch which is only operable from garage interior.

Insulated Door Door sections containing insulating material.

Insulation Material having ability to reduce heat or cold transmission.

Jackshaft Operator Electric operator is mounted on the wall at the end of the torsion spring shaft and directly drives the shaft.  Available in both commercial and residential types, and are available in light, medium, industrial and heavy industrial-duty. For use on high or vertical lift doors, rolling doors and grilles. Should not be used on Low Headroom or Standard Lift without “Pusher Springs”. 

Keypad Most keypads are wireless. Enter a 4-5 digit code and keypad communicates with the receiver on the opener to operate your garage door. Offers convenient access for when you don’t have a key or remote on hand.

Lift Clearance  (See “High Lift” and “High Lift Track”)

Lift Handle A handle, normally located on the bottom section of garage door, to provide safe gripping point when manually lifting a sectional garage door.

Lock Cable Cable that connects locking handle to side latch.

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

Long-Stem Roller Roller with a shaft length of 7 inches or longer.

Low Lift Hardware (Also known as “Quick Turn Bracket”) Low headroom accessories which enable a door system to operate in minimal headroom conditions.

Meeting Rail Top horizontal rail or bottom horizontal rail of any section that meets and joins to form a weatherproof seal.


Overlay Decorative ornaments of metal, wood or hardboard used for outside decoration of garage door sections.

Operator See “Garage Door Opener”

Panel The area between stiles in a door section. They are rigid and injected with high density pressure-injected polyurethane and having wood end blocks. Standard door height is usually comprised of 4 or 5 panels.The “look” of a door is considered the “panel style.”

Perforated Angle Angled metal with a series of punched holes used to hang garage doors and openers.

Perimeter Seal Weatherstripping installed at the perimeter of a garage door.

Pinch Resistant A term for a door that has been designed to prevent injuries such as crushing, entrapping, breaking, severing or dislocating a person’s finger between garage door sections.

Photo-electric sensors/Photo Eyes See “Safety Reversing Sensor”

Polyurethane A type of foam insulation Injected into garage door sections to ensure a high thermal-resistance rating and solidness.

Properly Balanced Door It is important that a garage door be properly balanced. Its dead weight should be between 10 and 20 lbs. (5 and 10 kg). If the door feels heavier than that, the source of the problem must be identified and corrected (ex.: springs that have lost their effectiveness)A properly balanced garage door should operate with minimal effort by hand, and will reduce the amount of strain on your garage door opener as it works to lift the weight limits it was designed for. When properly balanced, a garage door should be able to be stopped at any position.

Pull Down Rope A rope connected to the bottom bracket used to manually pull the door down.

Pusher Springs Pusher springs are installed at the end of horizontal tracks to assist a door in lowering safely. Normally used for standard movement (regular or Low Headroom) doors, and especially when a jackshaft opener or chain hoist is installed.

Qualified Electrician All electrical work including wiring, conduit and connections for electric garage door openers MUST be done by a qualified electrician. Our garage door specialists will install electric openers and their accessories, but they cannot connect them to the building’s power supply.

Quarter Turn A unit of turn measurement when winding tension of a torsion spring.

Quick Disconnect Door Arm Attaches garage door to automatic opener and allows quick disconnect to allow door to be manually opened (in the event of a power failure).

R-Value A measurement of thermal efficiency of a garage door, or how well the garage door insulates. The higher the R-value, the increased thermal efficiency of a garage door.

Radius Curved section of track that transitions from vertical to horizontal track welded, bolted or riveted to the horizontal track and then bolted to the flag angle. The curve is measured in inches, thus determining headroom requirements. See “Headroom.”

Rail  Horizontal member of a section.

Rail Components Garage door opener rail assembly parts include T-rail, chain or belt, travelers assembly, front idler bracket.

Raised Panel Door Design A raised and decorative design on door sections.

CHI Raised Panel - Durham Region ON
CHI Raised Panel Long with Sherwood Windows

Rate of Rise Measurement of change per revolution of a drum’s moment arm.

Residential  A sectional overhead type door which is intended for use in a residential garage, and normally operated less than 1,500 cycles per year.

Roller Assembly (Also known as “Track Roller”) A combination of a wheel and axle that is used to guide a garage door through the track system, and essential to the proper operation of a garage door. They are available in 2″ and 3″ sizes (depending on track size) and come in nylon, steel and plastic, with and without ball bearings. Available as short or long stem.

Roller Bracket A device that is mounted to a door section and holds a track roller.

Rollers (“Track Roller”) Steel, ball-bearing wheels or nylon rollers that allow sections to roll freely along garage door tracks.

Garage Door Parts: Roller


Safety Beams/Safety Sensor Safety sensors project light beam across garage door opening, and automatically reverses door if anything interrupts the beam. Garage door openers manufactured since 1993 are required to include photo eyes/motion sensors – mounted no higher than 6 inches above the ground, which reverses upon contact with about 15 pounds of pressure/resistance.

Safety Bottom Bracket See “Broken Cable Device”

Section A single segment of a sectional garage door that extends the full width of an opening; usually joined together by hinges. Garage doors are comprised of multiple sections to fill the appropriate height of a garage door opening. Typically, 7′ tall doors are typically comprised of 4 sections spanning the width of an opening.

Sectional-Type Door Door made of two or more horizontal sections hinged together, providing a door capable of closing the entire opening and which is by means of tracks and track rollers.

Sideroom  A horizontal measurement from each side of the door opening, outward to the nearest obstruction. Minimum sideroom of 3-3/4″ should be available on each side of door on interior wall surface to allow for attachment of vertical track assembly

Single Door  Commonly used to refer to smaller width doors used on one car openings.

Spring Assembly Hardware used to make up the garage door counterbalance assembly. WARNING: Springs are under extreme tension. We strongly recommend leaving any necessary repairs to trained professionals.

Spring Balance The amount of turns necessary to counterbalance the weight of the garage door.

Steel End Caps 16 ga. steel caps installed on end of the door panels – used with single or double hinges. Recommended for high cycle doors. End caps create thermal bridge between exterior and interior surfaces.

Step/Lift Plate A part that can be used as a lift handle or a step down plate for manually operating a garage door.

Stile Vertical reinforcement of a section.

Striker Plate A plate used along with a locking system to secure a lock mechanism.

Strut U-shaped reinforcement hardware that attaches horizontally to the inside of the garage door section (and runs the span of section) to add rigidity and strength. Wide, heavy garage doors require struts to help prevent buckling and sagging while the door is in the horizontal position, and increases the windload capability.

Thermal Break The separation between the outer and inner surfaces of a door section.

Top Bracket/Top Fixture  Adjustable bracket mounted on top section of garage door (in top corner) to position top roller and adjusts top section for tight fit.

Top Rail Horizontal rail forming the top of a door as distinguished from the meeting rails and bottom rail

Top Seal Weatherstripping which fastens to top of the door to form a seal along the top of the opening.

Torque The twisting force around an axis.

Garage_Door_Parts-TorsionSpring DurhamRegionON

Torsion Spring A garage door has one of two types of counterbalance spring systems – an extension spring system or torsion spring system. Torsion spring is a counterbalance spring which provides balancing power by winding and unwinding through the door cycle, and is considered the safest spring system. It works in the manner of twisting one end or part about a longitudinal axis while the other end is held or turned in the opposite direction developing torque. WARNING: Springs are under extreme tension. We strongly recommend leaving any necessary repairs to trained professionals.

Torsion Spring Shaft Tubular or solid shaft for torsion spring counterbalance assembly.

Track Channel shaped metal bars that provides a guide for the roller wheels on sectional garage doors.  (See “Vertical Track” and “Horizontal Track”). There are different types of tracks such as Standard or Low Headroom.

Track Brackets A fixture, connected to a rack which is designed for the track to be mounted to the jamb.

Trajectory The arc of travel or sweep of the top section as the door is raised from closed to open position. When planning the location of light fixtures and pipes, it is important to determine the trajectory.

Turn 360-degree revolution of a component about its axis.

Turns on Spring See “Winds On Spring”


Vertical Lift Refers to a hardware design that causes doors to open vertically where no horizontal tracks are required.

Vertical Track Assembly Mounted to the jambs with brackets on each side of the garage door opening, which guides and supports the garage door vertically in the closed position.

Wall Control Panel This panel Is commonly mounted inside the garage next to the door which leads into the house. It opens and closes the garage door and may have other features which allow homeowner to control garage lighting, disable remotes and keypads with a lock-out button, and see important system status messages.

Weatherstrip Material used at the perimeter of a garage door, intended to improve a door’s performance against air infiltration and thermal transmission.

Wind Load The amount of force the wind exerts along the face of a garage door as it stands in a closed position.

Winding Cone/Winding Sleeve Part that fits into a garage door torsion spring which permits winding of the torsion spring and tension adjustment. WARNING: Parts are under extreme tension.

Winding Rod A solid rod that fits into the socket of the winding cone to tension torsion springs.

Window Lite Glazing (glass or clear plastic) that is mounted in a door. The number of panels in a section limits the quantity of lites that can be installed. May be double glazed for insulation value. See “Full Vision Section.”

Winds on Spring The number of winding turns on a torsion spring.

Now you know your garage door!


Share this post