Glossary of Terms and Definitions

Search for window, doors or siding terms in our glossary

ABC Chart
A – Air Tightness the highest rating for air is A3; B – Water Tightness, the highest rating for water is B7; C – Wind Load Resistance, the highest rating for wind is C5.

Accent Moulding 
Half-round and square mouldings that provide a distinctive mode of expression to doors.

Thermoplastic glazing material.

Active Coils 
The number of working coils in a torsion spring.

Support member used to fasten torsion spring assembly of a vertical lift door to the wall above the door opening.

Air Infiltration 
Air movement through the building envelope. In the case of windows the CSA A440 standard for windows, the “A” measurement rates air infiltration.

Aircraft-Type Cable 
Several strands of galvanized wire rope braided together.

The space in the cavity between two panes of glass in an insulating glass unit.

A light weight metal used for building components.

Anchor Brackets 
Metal clips used to secure frame to jackstud.

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

Angle Iron
Length of L-shaped steel material generally used to support and brace rear of horizontal tracks from roof construction or ceiling.

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

A hard non-corrosive oxide film on the surface of aluminum.

Flat trim piece placed horizontally just beneath the window stool.

Arch Top 
A term used to describe a window unit with the curved frame. These units, also called curved-tops or round-tops are often placed over another window.

Argon Gas 
A non toxic gas used in insulating glass units to reduce heat transmission.

The center member of a double door, which is attached to the fixed or inactive door panel.

Automatic Latch 
An automatic door locking device.

Awning Window 
A window unit, similar to a casement, hinged along the top, where the bottom of the sash swings outward.




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

A mechanical device used in single and double hung windows to offset the weight of the sash during opening and closing. Spiral balances as well as weights and pulleys are used.

Bar Joist 
A lightweight truss adaptable for the support of roof decks.

Bay window
A composite of three or more windows, usually made up of a large center unit and two flanking units at 30°, 45° or 90° angles to the wall.

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

Blind Rivet 
A type of fastener that mechanically joins two pieces of material together by means of a riveting tool.

Bottom Rail 
The bottom horizontal member of a window sash or door.

Bow Window 
A composite of four or more window units in a radial or bow formation.

Brick Mould 
Outside casing around window to cover jambs and through which nails are driven to install the window.

Broken Cable Device 
A bottom fixture intended to prevent a door from falling in the event of cable breakage.

A fixed or removable lining used to constrain, guide, or reduce friction.

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

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

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

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

Cam Lock 
A lever operated lock which is used to lock the sash into the frame.

The dividers between glass bevels in decorative glass door inserts.

Window with sash cranking outward, to the left or right.

Exposed moulding or profile around a window or door, on either the inside or outside, to cover the space between the window frame or door jamb and the wall.

A compound for filling joints and sealing cracks to prevent leakage of water or air.

Cellular PVC 
Extruded polyvinyl chloride material used in window and door components and trim. Unlike rigid vinyl, it features a foam or cell structure inside. It can often be nailed, sawn and fabricated like wood.

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. (Commercial garage door application)

Center Stile/Mutt
Vertical members of a garage door section that provide structural rigidity and location for center hinge attachment. (Commercial garage door application)

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.

Chain Hoist 
Adds mechanical advantage to manually-operated garage doors. Couples to one end of the solid torsion shaft. (Commercial garage door application)

Hollow sections designed into uPVC frames to provide added structural strength, insulation and noise reduction.

Check Rail 
On a double-hung window, the bottom rail of the upper sash and the upper rail of the lower sash, where the lock is mounted.

A generic term referring to any of a variety of window units with one or more curved frame members, often used over another window or door opening.

Another term for siding. A thin material made of vinyl or aluminum, fitted over wood sash, door jamb or window for weather protection and finish color.

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

Clerestory Window
A venting or fixed window in the upper part of a high room that admits light to the centre of a room.

Colonial Grill 
An internal, rectangular grill bar used in a number of different grill designs.

Combination Door
A screen or storm door used in combination with a primary door. Storm windows also are referred to as combination windows.

Complete Tear Out Window Install
A method of installing a replacement window where the older window is completely removed back to the original window opening (RSO).

A term used for window and door components that consist of two or more materials, such as fibers or wood and plastic. The term also is used for windows and doors that combine two or more materials in the frame or sash construction, such products as a wood interior and vinyl or aluminum exterior.

Water vapor from the air deposited on any cold surface that has temperature below the dew point.

Heat transfer through a material. Heat flows from a higher-temperature area to a lower-temperature area.

Cottage Double-Hung
A double-hung window in which the upper sash is shorter than the lower sash.

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.

The short 2″ x 4″ members used to frame under the sill or above the header in a rough opening for a window in a frame wall.

A watertight wall or frame used to raise slope glazing above the surface of the roof as a preventive measure against water leakage from melting snow or rain run-off.

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

Curved Top
A term used to describe a window with a curved frame. These units, also called arch top or round top are often placed over another window.

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.

Daylight Opening 
The measurement denoting the width and height of visible glass in that order.

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

Design Pressure
A numerical value that defines the structural wind loading requirements (in pounds per square foot) for a building and the components and cladding of a building.

Direct Set 
Refers to a unit in which the glass is glazed directly into the frame, with no sash members. The unit is stationary.

Divided Lites 
Separately framed pieces or panes of glass. A double hung window, for instance, often has several lites divided by muntins in each sash. These designs are often referred to as six-over-six or eight-over-eight etc…, to indicate the number of lites in each sash. Designs simulating the appearance of separately framed panes of glass are often referred to as SDLs or simulated divided lites. Designs using actual separate pieces of glass are sometimes referred to as TDLs or true divided lites.

Door Frame
A complete door frame consists of two jamb legs, header and sill.

Door Size
Always specify the width first and the height second: for instance 8′ 6″ (2591 mm) wide by 7′ 3″ (2210 mm) high. Refer to “Opening Size.”

Door Skin 
A single sheet of material used as the face of the door.

Door Slab 
A complete door panel that has not been assembled into a frame.

A space which protrudes from the roof, usually including one or more windows.

Double Glazing 
Use of two panes of glass in a window to increase energy efficiency and provide other performance benefits.

Double Hung 
A window with two vertical operating sash that slide up and down.

Double Rafter
The doubling (side by side) of the roof members to reinforce an opening in the roof for a slope-glazing installation.

Double-Thick Glass 
Lighter than plate glass, about 1/8″ (3.18 mm) thick, often termed double-strength glass. See “Glass Type.”

Drip Cap
A moulding placed on the top of the head brick mould or casing of a window frame.

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
A combination of two torsion springs.

Egress window 
A window large enough, as defined by local building codes, for exit or entry in case of an emergency. Typically required in bedrooms.

Electric Operator 
An electrically operated device which will open awning windows by using a switch. This is used in lieu of a roto gear crank or pole crank.

The relative ability of a surface to reflect or emit heat by radiation. Emissivity factors range from 0.00 to 1.00 and are typically measured in U-Factor (or its inverse R-Factor). The lower the emissivity, the less heat that is emitted through a window system.

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

Endvent Slider 
A window with a horizontally sliding sash on each end and a fixed unit in the centre. Generally the sliding units are quarter the width of the entire unit and the centre section is half the width.

Energy Rating (ER)
A measure of the thermal performance of a window. A window’s air infiltration and solar heat gain are used to calculate that window’s ER. ER numbers range from 0 to over 40. The higher the ER number the better the energy performance.

Energy Star 
A program sponsored by Natural Resources Canada. ENERGY STAR qualifies windows that meet minimum energy performance criteria.

A 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. (Commercial garage door application)

Extension Jam
Wood or PVC pieces attached and extending from a window or door frame to accommodate different wall thickness.

Extension Springs
Counterbalance 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.

A form produced by forcing heated material through a die.

False Mullion 
A mullion simulating the look of a single hung window on a casement or a picture window. The unit is divided by a strip of vinyl (similar to the divided lites).

An architectural term referring to the arrangement of windows in a wall.

A means of joining individual pieces of wood together to form longer lengths. The ends of the pieces are machined to form a set of interlocking fingers, which are then coated with adhesive and meshed together under pressure.

Fire Door 
Fire doors are designed to meet independent testing for some applications where the fire code has specified this product.

Fixed Lite 
Non venting or non operable window.

Fixed Panel 
Non operable door usually combined with an operable door unit.

Non-venting or non-operable.

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

The two end windows in a multiple unit.

A strip of metal or vinyl that diverts rain water away from a wall or roof assemble.

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

If a sealed glazing unit fails, the moisture or the residue from evaporating moisture that collects on the inside surfaces is called “fogging”.

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. (Commercial garage door application)

The main structural element of a window composed of two vertical side jambs and two horizontal components called a head and sill. The window sash fit (s) inside the window frame.

French Door 
Generally refers to a pair of hinged doors that open from the middle.

French Hinged Door
Hinged door(s) which have wider panel members around the glass.

French Sliding Door
A sliding door which has wider panel members around the glass, giving the appearance of a French hinged door.

Front-Mounted Low Headroom
Low headroom hardware where springs mount on torsion shaft above opening. (Commercial garage door application)

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. (Commercial garage door applica

Full Vision Section
A 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. See “Glass Type.” (Commercial garage door application)

Fusion Welded 
The process of joining uPVC materials by melting them together with extreme heat, resulting in the materials uniting or welding into a one-piece unit.

Zinc coating to protect steel against corrosion.

Garden Window
A window that projects beyond the outside surface of the adjacent wall. These windows are designed to accommodate the growing of potted plants.

A pliable, flexible continuous strip of material used to effect a watertight seal between sash and frame of roof windows much like the seal around a refrigerator door.

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. (Commercial garage door application)

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. (Commercial garage door application)

Glazing Bead 
A plastic or wood strip applied to the window sash around the perimeter of the glass.

Glazing Compound 
A pliable substance applied between the window sash and the lights of glass to seal against the elements and sometimes to adhere the glass to the sash.

Glazing Stop 
A component of the sash or door panel that holds the glass in place.

The glass panes or lights in the sash of a window. Also the act of installing lights of glass in a window sash.

Grill (Internal) 
Small bars that visually divide a window into panes. Comes in various sizes, colours and configurations. See also True Divided Lite.

Grill (Wood) 
Removable wood dividers (interior only) made to simulate True Divided Lites.

Half Round 
A fixed picture window which is one half of a full circle.

Hard Coat Glass 
A glass product that is coated during the manufacturing process at the molten glass stage. Also known as a pyrolytic coating. The other type of glass coating is a sputter coat which is applied in a secondary process. Sometimes referred to as soft coat.

Handles, cranks, locks, tilt mechanisms, etc.

Head Board
A flat board cut to fit the contour of a bow or bay window and installed between the head jambs and the flat wall surface to finish off that area which would normally be ceiling.

A horizontal framing member installed above a door or window to transfer the building’s load from above the opening to the supporting wall structure on either side of the opening. A properly sized header keeps the structure from sagging, or worse yet, collapsing at the window opening. Header size is based on the rough opening size, the bigger the window, the stronger the header must be. Factors like overhead floor length and joist spacing may be involved in calculating header size. Check with your local building inspector for requirements.

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

A 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.

Heat Gain 
The transfer of heat from the outside to the inside by means of conduction, convection and radiation through all surfaces of a house.

The vertical dimension.

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

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.

A window with a top sash that swings inward.

Horizontal Slider 
A window with a movable sash that slides horizontally.

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. See “Radius.”

Hung Window 
Window style in which one or both sashes slide up and down.

Impact Resistant Glass 
Single or double pane construction made up of laminated glass containing a .090 interlayer.

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

Inex Spacer 
Low conductance spacers (INEX) that reduce heat transfer near the edge of insulated glass units.

Heat loss due to air escaping through cracks or spaces around an exterior door or window.

Inside Lock 
Spring loaded, sliding deadbolt lock operable only from the interior of the garage door.

Insulating Glass (IG) 
Two or more lites of glass with a hermetically sealed air space between the lites. The sealed space may contain air or be filled with an inert gas, such as argon.

Material that has the ability to reduce heat or cold transmission.

J Channel 
Trim for siding used primarily at the sides of windows and doors.

Jack Stud
Framing members, generally 2″ x 4″s, which form the inside of the window or door rough opening. They run from the sole plate to the header, which is supported by them.

The side and head trim of a door or window frame.

Jamb Depth 
Width of a window or door from the interior to the exterior of the frame.

Jamb Extension 
A frame member which is added onto the jamb of a door or window to extend the frame to match wall thickness. Can be wood or uPVC.

Jamb Liner 
Metal or plastic covering the inside surface and head jambs of sliding windows.

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

The protruding, hook-shaped part of a casement window lock, which is mounted on the inside surface of the sash stile.

King Studs 
The wall studs that run the entire length of the wall that trimmer studs attach to.

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

Laminated Glass 
Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken. Used for enhanced safety and security, as well as sound reduction.

Handle or grip installed on the bottom rail of the lower sash of a double-hung window to make it easier to raise or lower the sash.

Lift Clearance 
Refers 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 Rail 
The lip that is attached to the sash of a slider window to allow the homeowner to grasp and open the window.

A handle, normally on the bottom section of the garage door, to assist in manually lifting the sectional door.

Light or Lite
Glazing framed by muntins and/or sash in a window or door.

Light shaft 
An insulated shaft built to direct the light from a roof window or skylight through the attic to the room below.

A structural component or beam above a window or door opening that supports the wall above. Also referred to as a header.

The complete lock system comprised of the lock mechanism together with knobs, keys, plates, strikes, and other accessories.

Low – E Glass 
Low-E stands for low emissivity. Low-E glass reduces radiant heat transfer through the glass lowering home heating and cooling costs.

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

Masonry Openings 
The opening in a masonry wall to accept a window or door unit, the same as a rough opening in a frame wall.

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 ihas 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. (Commercial garage door application)

Medium density fiberboard. A wood fiber composite used in a variety of window, door and millwork applications.

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

Generally all building components of finished wood that are made in a woodworking plant or planing mill. Includes doors, window sashs, door frames and window frames as well as stair components, trim moldings, mantels and wainscot panels.

Mineral Core 
Fire rated core of a door available in 45 mins, 60 mins & 90 mins.

An ornamental exterior trim around the perimeter of a frame.

A slot or rectangular cavity cut into a piece of wood to receive another part.

A strong wood joint made by fitting together a mortise in one board and a matching projecting member (tenon) in the other.

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

Movable Center Post 
A 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. (Commercial garage door application)

The vertical or horizontal divisions or joints between single windows in a multiple window unit.

Mullion casing 
An interior or exterior casing member to cover the mullion joint between single windows.

Multipoint Lock 
A locking system, operated with one handle that secures a window or door at two or more locking points.

A short bar used to separate glass in a sash into multiple lights. Also called a windowpane divider or a grille.

Nailing Fin 
A thin leg extending beyond the outside surface of a window frame. A nailing fin covers the spaces between the window and the window opening in the wall. A nailing fin provides temporary fastening of a window. Permanent fasteners pass through window jambs at shim locations.

National Fenestration Rating Council® -a non-profit organization that provides fair, accurate and credible energy performance ratings for windows and doors.

Night Latch 
A safety device available in some windows that allow the sash to be opened a few inches for ventilation, but prevents maximum opening.

Obscure Glass 
Glass formed by running molten glass through special rollers with a pattern on them causing the glass to become obscure. Most often used in bath rooms for privacy. Also known as frosted or privacy glass.

An eight-sided window.

Offset Hung 
A Double or Single Hung window in which the two sash heights are unequal or offset from centre.

Size Frequently called daylight opening or finished opening. Dimensions are taken between masonry or wood walls or between steel jambs.

A metal arm and gear which allows for easy operation or closing of projecting windows.

frame member The exterior protruding portion of a window frame which has no exterior casing.

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

Refers to the wood framing at jambs and header to which the garage door track is mounted. Usually furnished by general contractor. See “Jambs.”

window A large, arch-top window flanked by smaller windows on each side.

A component of a sliding glass door, consisting of glass in a frame installed within the outer frame of the door.

Parting Strip 
The small strips of wood placed in the side and head jambs of a double hung window to separate the upper and lower sash.

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. Cannot be used as a legal exit. (Commercial garage door application)

Passive Solar Collector 
Any glazed area in the walls or roof of a building pointed to the south to take maximum advantage of the sun’s heat without a mechanical (or active) method of storage or distribution of the heat.

Passive Solar Heat Gain 
Solar heat that passes through a material and is capturerd naturally, not by mechanical means.

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

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.

Picture frame casing 
The use of casing on all four sides of the interior of a window, replacing the stool and apron at the sill. Also known as full-bound casing.

Picture Window 
A window with no operating hardware. Can be Fixed Picture, which has a narrower frame with more glass area or a Fixed Casement, which has a wider frame to match the operating Casement and Awning windows.

The pitch of a roof is the degree of the inclination upward from horizontal or flat. It may be expressed in degrees or as the ratio of the number of inches it rises in each 12 inches of horizontal span: 4/12 means the roof rises four inches in every foot of horizontal span.

A mode of operation for ventilating windows which generally means the sash pivots on a central axis and turns 90 or more degrees.

Prehung Door 
A door already mounted to the jambs, eliminates steps of fitting the hinges and squaring door.

Prime Window 
A primary window, as opposed to a storm or combination unit added on.

PVC (polyvinylchloride) 
A thermoplastic material used for building components.

Quarter Round 
A fixed picture window which is one quarter of a full circle.

A groove along or near the edge of a piece of wood.

Rabbeted Joint 
Joint formed by connecting rails with grooves cut out in opposing edges to permit overlapping weathertight meeting of sections. See “Shiplap Joint” and “Tongue-and-Groove.”

The transfer from heat and/or light energy through the atmosphere.

The curved portion of the track, which allows the door to move from vertical to horizontal (and vice versa). The curve is measured in inches, thus determining headroom requirements. See “Headroom.”

Structural members of a roof that support the roof load and run from the ridge to the eaves (overhang).

The cross or horizontal members of the framework of a sash or door panel.

Rain or Water Stop 
A 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. See “Back Hangs.”

Reflective Glass 
Window glass coated to reflect visible light and solar radiation striking the surface of the glass.

Relative Heat Gain (RHG) 
A calculated relationship of heat gain (through a window system) that accounts for center-of-glass U-Value and center-of-glass shading coefficient based on a standard inside and outside temperature.

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. (Commercial garage door application)

Retro Fit Window Installation (insert window) 
A method of installing a replacement window inside the frame of an older wood window.

Reverse Angle Mounting 
An exceptionally sturdy method of track mounting used on all steel jambs and wood jambs at the architect’s direction. See “Angle Mounted Track.” (Commercial garage door application)

Roller Assembly 
The 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. Available as short or long stem.

Steel, ball-bearing wheels that allow sections to roll freely along garage door tracks.

A decorative corner piece used with interior trim.

Roto Gear 
A term used to describe the steel drive worm and gears and crank device used for Casement and Awning Windows.

Rough Opening 
The opening left in a frame wall to receive a window or door unit.

Rough Sill 
The horizontal rough framing member, usually two inches by four inches, which forms the bottom of the rough opening. It is toe-nailed into the jack studs and is supported by cripples.

Round Top 
An arch top window which can be used separately or stacked to another window or door. Available in quarter round, half round, half ellipses, ellipses, full circles, cambered and gothic arch tops.

RSLO/LSLO Right side looking out/left side looking out. 
Used to indicate hand of chain hoist or electric operation or lite or exhaust port location. (Commercial garage door application)

The measure of a products ability to resist the transfer of thermal energy. A window with a high R-Value has greater resistance to heat flow and a higher insulating value than the one with a low R-Value.

Safety Glass 
A strengthened or reinforced glass that is less subject to breakage or splintering and less likely to cause injury if broken.

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.

The frame containing one or more panes of glass.

Sash Balance 
A system of weights, cords and/or coiled springs which assist in raising double-hung sash and tend to keep the sash in any placed position by counterbalancing the weight of the sash.

Sash Cord 
Rope or chain in double hung windows that attach the sash to the counter balance.

Sash Lift 
Protruding or recessed handle on the inside bottom rail of the lower sash on a double or single hung window.

Sash Lock 
A cam-action type lock applied to the check rails of a sliding window or at the open edges of a projecting window to pull the check rails tightly together or to seal the sash tightly to the frame, both for security and weathertightness.

Sash Stiffener 
A reinforcement, usually inserted into a sash profile prior to assemble, designed to increase the strength of the unit.

Sash Weights 
In older double-hung windows, the concealed cast-iron weights that are used to counterbalance the sash.

Screen (Full and Half) 
Screen material of fiberglass mesh attached to an aluminum surround. Screens inhibit entry of insects, yet permit light, air and vision. Double Hung, Double Slider, Casement and Awning utilize full screens; half screens are available on Single Hung and Single Slider units. They are not child resistant and cannot be used as a security feature.

Seat Board 
A board attached to the bottom of a bay or bow window, providing support and a flat surface.

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.

A series of straight pieces joined together to create the appearance of a radius.

Shading Coefficient
The ratio of solar heat gain through the glass relative to that through 1/8″ (3mm) clear glass under the same set of conditions. The smaller the number, the better the glass is at stopping solar heat gain.

Shaft Bearings 
Type 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 
A tubular or solid steel counterbalance shaft transmits the lifting force of the torsion springs to the cable drums and lifting cables.

A 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.

A wedge or strip of wood used to level a window or door in the rough opening.

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. See “Tongue-and-Groove.”

Side Jam 
The vertical pieces of a window or door frame.

Narrow fixed units mulled or joined to operating door units to give a more open appearance.

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

The framing member forming the lower side of an opening that supports the window’s weight. The sill is supported by cripple studs.

Sill Pan 
A product placed under a window or door during the installation process that is designed for water drainage.

Simulated Divided Lites (SDLs) 
A type of grille or grid design that creates the appearance of a number of smaller panes of glass separated by muntins, but actually uses larger lites of glass with the muntins placed between and/or on the surfaces of the glass layers.

Single Glazing 
Use of a single lite of glass in a window. Not as energy efficient as insulating glass or other forms of double glazing.

Single Hung 
A window resembling a double hung, or vertically sliding window, with a fixed top sash.

Main surface of a door. Door slabs come in different gauges and are hot dipped galvanized steel, primed white or prefinish white.

Sliding Patio Door
Glass sliding door available in a Mechanical or Welded Sash design.

Slope glazing 
Any glazed opening in a sloped roof or wall, such as a stationary skylight or fully operable roof window.

Material running from the back of the fascia board to the wall, usually made of plywood, vinyl or aluminum. Soffit is often vented to allow air movement into the space under the roof.

Soft Coat Glass 
A glass product that is coated in a secondary process known as sputter coating, usually to offer low-emissivity or solar control benefits. Hard coat or pyrolytic glass is coated during the manufacturing process at the molten glass stage.

Solar Control Glass
Glass produced with a coating or tint that absorbs and reflects solar energy, thereby reducing solar gain.

Solar Gain 
The process of providing a net heat gain within a structure, over and above the normal heat loss, by passive collection of the sun’s heat through windows and other glazed areas.

Solar heat Gain Coefficient (SHGC)
An NFRC (National Fenestration Rating Council) rating. Measures how well a product blocks heat caused by sunlight. Ratings range between 0 and 1. The lower the SHGC, the less heat is transmitted indoors. Generally, a lower SHGC is desirable in warm climates and a higher SHGC is desirable in cold ones.

Sole Plate 
The bottom horizontal member in a frame wall. Usually either single or double 2″ x 4″s. It is nailed to the deck or rough floor and the studs are nailed into it.

Solid Core 
Wood block, particleboard or fire rated mineral fiber used in the core of a door. Solid core doors are either flush or raised panel.

Sound Transmission Class (STC)
A rating measuring a window’s acoustic properties or its ability to reduce sound transmission. An STC rating is determined by measuring the sound transmission over a selected range of sound frequencies. The higher the number, the less sound transmitted.

Spring Anchor 
Plates Designed 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. See “Center Support Bearing.”

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. (Commercial garage door application)

Spring Fittings
The 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.

Stacked Unit 
A combination unit where one unit is fixed on top of another.

A non-operating, fixed sash, panel or unit.

Steel Jamb Mounting 
Continuous angle attached to vertical track and fastened to the jamb by welding, self-tappers, or bolts. (Commercial garage door application)

The vertical members of window sash and panel doors.

Horizontal trim piece attached to the sill. The bottom rail of the lower sashs in a double hung window rests against the stool

Small molding strips attached to side and head jambs to guide and stop moving sash and swinging doors.

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.

Straight Incline Track
Vertical track assembly that extends from floor to twice the height of the opening without break-away feature. See “Break-Away Track.” (Commercial garage door application)

L-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.

Vertical wood framing members which form a frame wall. In normal construction these are eight foot-long 2″ x 4″s.

Tempered Glass 
Glass that has been through a special heat-treated tempering process that increases its strength. When shattered, the glass breaks into small pebble-like pieces to reduce injury. Note that glass must be cut to size before it is tempered.

A rectangular projection cut out of a piece of wood for insertion into a mortise.

Used in place of a crank handle on Casements or Awnings to allow for interior blinds.

Thermal Break 
A thermally insulating or low conductance material used between interior and exterior aluminum (or other conductive material) window and door components.

Thermal Performance
The ability of a window to act as a barrier to the transfer of heat.

Thermal Transfer
The movement of heat or cold through a substance.

An aluminum or wood member, bevelled or tapered and used with exterior or interior door sills.

Tilt Window 
A single or double hung window whose operable sash can be tilted into a room to allow cleaning of the exterior surface on the inside.

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.

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.

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 (See “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.

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.

A small window above another window or door. Usually used for additional light and more rarely for ventilation.

Trimmer Studs 
Studs that support the header and transfer structural weight from the header down to the floor. Trimmers serve as framing for nailing side jambs.

Triple Glazing
A sash glazed with three lights of glass, enclosing two separate air spaces.

True Divided Light
Traditional window construction incorporating smaller panes of glass actually separated by muntins, rather than simulating such an appearance with larger lites of glass and a muntin grid or grill placed between or on the surfaces of the glass layers.

A measure of heat transmission through a window. A lower value indicates less heat transference therefore better the insulating value which leads to better energy efficiency. The reciprocal of R-VALUE.

Ultraviolet or UV Light 
Invisible rays produced by the sun that can cause fading of furniture fabrics, carpets and paint finishes.

Unison Lock 
A casement locking system which secures the window at two locking points by operation of one handle.

Unplasticized polyvinyl chloride makes vinyl rigid.

Vapor Barrier
A watertight material used to prevent the passage of moisture into or through floors, walls and ceilings.

Venting Unit 
A window or door unit that opens or operates.

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

Vinyl (or uPVC) 
Unplasticized polyvinyl chloride. The type of vinyl used in our windows.

Warm Edge 
A type of insulating glass construction using an airspacer offering lower thermal conductance than traditional aluminum spacer. Warm edge IG units typically offer higher resistance to condensation and an incremental improvement in window energy performance.

Weather Stripping 
A strip of resilient rubber or pile material designed to seal the sash and frame members in order to eliminate air and water infiltration.

Weep Hole
A small opening in a window or sill member through which water may drain to the building exterior.

Wicket Door 
Hollow-metal pedestrian door installed adjacent to the sheet door that shares the same building opening. (Commercial garage door application)

Wind Bourne Debris 
Region Areas within hurricane-prone regions within one mile of the coast where the basic wind speed is 110mph or greater, or where the basic wind speed is equal to or greater than 120mph.

Winding Bars 
Used 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.

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

Force exerted on surface by moving air.

Window Rating 
The level of performance for strength and weatherproofness of windows and doors as determined by test. Window ratings are expressed in design wind pressure terms.

Window Styles 
Single Hung, double hung, single horizontal, double horizontal, casement, awning, octagonal and specialty shapes.

Windowpane Divider
A short bar used to separate glass in a sash into multiple lights. Also called a muntin or a grille.

Wood Jamb Mounted 
Regular method of mounting vertical track to wood jambs.

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


A unit of length equal to 3 feet or 36 inches.

Zero Clearance Opener 
Opener that fits applications where there isn’t enough room for a traditional “boom” type opener.

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