Helpful terms and definitions for windows and doors
Primary operating door panel.
The aluminum frame around a screen or energy panel
A piece of casing or decorative trim installed against the wall immediately beneath the stool of a window.
A colorless and odorless gas used to fill the airspace between insulating Low E glass. The addition of argon greatly increases the insulating performance of the Low E glass.
Single units mulled together.
A moulding applied to one stile of a French Door, Sliding French Door or French Casement window unit which the other door panel or window sash strikes. Usually head and footbolt devices will be found on the astragal side.
Authentic Divided Lites (ADL)
Also known as True Divided Lite. Permanent stationary muntins and bars separate the glass in a window or door sash to give the sash two or more lites of glass.
Awning Window Unit
A combination of frame and sash, hinged at the top of the vertical jambs which allows the unit to pivot from the top with the sash opening to the exterior of the building.
A block and tackle system used in the jamb liner of double hung or single hung units.
A narrow rabbeted, horizontal or vertical sash or door member in an authentic divided lite unit, extending from rail to rail or stile to stile along the total length or width of the glass opening.
A series of windows installed in a bay which is two flanker units and a center sash; a bay may be an arc or a polygon; when a bay is or closely approaches an arc, the window is termed a bow. See Bow Windows.
The frame member on a double hung window located between the jambs and the casing. The blindstop forms a rabbet that supports either a storm sash or screen.
A series of adjoining window units, installed on a radius.
Brick Mould Casing BMC
An exterior moulding of window and door frames that abuts the exterior facing material of the structure. The casing serves as the boundary moulding for brick or other siding material and also helps to form a rabbet for screens and/or storm sash or a combination door.
A tube inserted into the insulating glass spacer that allows the inside and outside air pressure to equalize in higher elevations.
A combination of frame, sash, weather-strip, concealed hinges and operating device assembled as a complete and properly operating unit. Casements have a flat sill and a sub-sill; screens and/or energy panels are optional. Operating casements have a crank handle for smooth operation.
Clad Brick Mould Casing (BMC)
A clad extrusion designed to simulate brick mould casing for window clad products.
Manufacturer’s clad products refer to wood window and door parts which are covered with an extruded permanent colored aluminum jacket on the exterior side of the frame and sash.
The plastic and metal assembly on which the cam pivots of a double hung or single hung sash rest. The clutch is attached to the block and tackle system of the balance tubes which allow opening and closing of the sash. The clutches are color coded for easy identification of balance strength.
A wood or aluminum storm sash with self-storing screen and operating glass panels. Available for double hungs, gliders and wood swinging doors, these panels are removable.
A window with unequal sash, top and bottom.
Daylight Opening (DLO)
The width and the height of the visible glass.
Depth of the Jamb
The point where the exterior casing ends to the point where the interior casing begins. On clad units, the point from the backside of the nailing fin to the interior of the frame.
Refers to a window with no sash. The glass is glazed directly into the frame and is stationary.
Division of light by the use of muntin bars.
Muntins: The actual bars that create a pattern in the window.
Authentic Divided Lites (ADLs): Single or insulating glass, individually glazed between the muntin bars.
Simulated Divided Lites (SDLs): Muntins permanently adhered to the interior and exterior of the glass.
Grilles: Wood Muntins fastened to the interior of the sash to create the effect of divided lites, removable for easy glass cleaning.
Spacer Bar: Tiny aluminum bars inserted between SDL muntins to emulate ADL.
Grilles Between Glass (GBG’s): Aluminum flat or contour bars divide the glass visually. Because the grille is between the glass, grilles do not become misplaced or damaged. Cleaning is easy without small panes of individual lites.
Double hung windows have two movable sash which operate vertically. Double hung sash are held in an open position with the use of coil spring block and tackle balancing devices.
A formed aluminum or vinyl piece which is installed at the top of windows and doors that allows water to run off the casing of the unit instead of seeping around the casing and into the unit.
An electrically operated device which will open casements or awnings units by using a switch. This is used in lieu of a roto gear crank or pole crank.
A decorative door handle plate attached to the stile directly behind the handle(s). Generally square or rectangular shaped.
An article or product of vinyl or metal-made by the process of extruding. Extrusions include vinyl sill and head jamb tracks, vinyl jamb liners and aluminum cladding used on the exterior of clad units.
A series of fingers machined into the ends of two pieces of lumber to be joined together. They are then held firmly in position by adhesive. Finger jointed wood is very strong and has a lesser chance of warping than does a clear piece of wood the same length.
A former term used to describe a side or lateral part. Also previously used to describe a 3-wide picture unit or bay. See two-wide entry.
Flat, surfaced on four sides, pieces of pine of various widths and thicknesses for trimming door and window openings. The casing serves as the boundary moulding for siding material and also helps to form a rabbet for screens and/or storm sash or combination doors.
A locking rod device installed vertically in the stile or astragal of a door or screen which when activated secures the panel or screen in a stationary position.
The stationary portion of a window that encloses either the glass (direct glaze) or the sash (operating or stationary) and consists of the head jamb (top), sill (bottom), sub-sill, side jambs, jamb extension, brick mould or flat casing, and blindstop.
A flat aluminum extrusion used in conjunction with the 90 degree frame expander to provide a flat casing appearance for clad units.
A casement styled unit with two sash in one frame providing a sense of openness unrestricted by a vertical mullion or stiles when both sash are open.
French Doors are available in either inswinging or outswinging rectangular or arch top style choices.
Glass Size (GS)
The measurement of the actual glass, not the visible glass.
Installing glass into windows and doors.
SINGLE GLASS: Glazing with a single piece of glass.
INSULATING GLASS: two panes of glass separated by a spacer and hermetically sealed together with dead air space between the panes.
Strips of profiled wood or vinyl used to hold the glass in position in the sash. Wood glazing bead is attached to the rails and stiles of the sash using staples, small nails or vinyl barbs. A vinyl bead is held in place by extruded barbs positioned in the kerf. Aluminum caps may be used over the vinyl bead in some cases.
A two sided adhesive tape placed between the glass rabbet and the glass and/or the glazing bead and glass of some unit types.
Horizontal operating units which have one sash fixed while the other glides open and shut horizontally.
Removable wood dividers made to simulate authentic divided lites.
A term used to describe the right or left hand operation of a window or door.
The top member of a frame.
A locking rod device installed vertically in the stile or astragal of a door or screen which when activated secures the door in a stationary position.
A term used to define a window or door product meeting the requirements of historical renovation standards.
Secondary operating door panel.
Insulating Glass (IG)
Inswing French Door
A French door with panels that swing to the inside. One, two, three and four panel units available as stationary or operating.
The casing trim used on the interior perimeter of the window or door. Generally supplied by others except in the case of round top casing which is factory supplied.
A jamb-like member, usually surfaced on four sides, which increases or extends the depth of the exterior or interior window or door frame; jamb extensions imply a larger depth than “wood jamb liners.”
Thin strips of wood attached to the head jamb, side jambs and sill to accommodate various wall thicknesses. Common jamb depths are: 4 9/16″, 4 13/16″, 5 1/16″ and 5 3/16″.
Keyed Cylinder Lock
A lock providing an exterior entry and locking convenience.
Inert gas known for its ability to provide insulating properties in a small air space.
Glass composed of two sheets of glass fused together with a sheet of transparent plastic between the sheets. When broken laminated glass will generally not leave the opening.
A method of gluing strips of thin clear wood to the lengthwise surfaces of finger jointed material to provide the appearance of clear stock.
A lever handle and lever arm operator available as an option on awning units.
A complete door 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. The lower the emissivity the higher the percentage of long-wave radiation blocked thereby improving thermal performance. Low E glass is coated with a thin microscopic, virtually invisible, metal or metallic oxide layer. The primary function is to reduce the U-value by suppressing radiative heat flow. A secondary feature is the blocking of short wave radiation to impede heat gain. There are two basic types of Low E glass. The first, vacuum or sputter coated Low E, is referred to as soft-coat (See Low E II definition). The second is pyrolytic Low E, commonly referred to as hard-coat. (See pyrolytic definition.)
A high performance Low E glass, providing the best winter U-value and warmest center glass. It offers significant improvement in reducing solar heat gain coefficient values, providing customers one of the coolest summer glass temperatures of all Low E products. Additionally, ultraviolet light transmission is greatly reduced. The Low E II coated glass products are specifically designed for insulating glass units normally as a second surface coating. See Low E and pyrolitic definitions.
A brick, stone or block opening into which a window or door unit is installed including the outside casing.
Mortise and Tenoning
The system by which assembles authentic divided lite units, a projecting tenon on either the muntins or bars fit snugly into a mortise in either a bar, stile or rail.
The act of attaching two or more window or door units together. The joint is then finished with a mullion center cap or mull trim.
The vertical member of a sash, window or door frame between openings in a multiple opening frame.
SPACE MULL: Two or more units mulled together with a space left between the units. The jamb extension surrounds the entire unit.
STUD POCKET: Two or more units mulled together with a space between the units. The jamb extension surrounds each unit separately, providing space for a support member between the units.
The 3/8″ mullion reinforcement is designed to be used on wood or clad multiple casement, awning and direct glaze assemblies to improve structural performance.
An adjustable lock system used on the French Casement to ensure a tight seal of the sash frame components. It also provides a secure locking system.
Multi-Point Locking System
A line of standard or optional multiple point locking mechanisms installed on the operative panel(s)/ sash of various products to enhance security and performance.
Muntins (or “munt”)
A short “bar,” horizontal or vertical, extending from a bar to a stile or rail or another bar.
A factory installed vinyl strip that is inserted into a kerf in the frame of clad units. Nailing fin installation is the standard method used for installing clad units.
A handle without a keyed cylinder. The door cannot be locked from the exterior.
Glass formed by running molten glass through special rollers. These rollers have a pattern on them causing the glass to become patterned and thus obscure.
The current term used to describe one frame with single or multiple sash or panels.
Our drawings always illustrate the window sash or door panels as if you are looking at it from the exterior. X means operating, O means stationary.
An operating sash, panel or unit.
Outswing French Door
A French door with panels that swing to the outside. One, two, three, or four panel units available as stationary or operating.
The letters OX or XO identify the operation of window or door units as viewed from the exterior. The letter O stands for stationary while the letter X stands for operating.
Either the stationary or operator wood frame with glass used on door products.
A strip of wood with weather-stripping attached which prevents air and water infiltration. Part stops are commonly found at the head jamb of a double hung unit.
A term used to describe the angle of a roof. For example: A 4-12 pitch indicates that the roof rises 4″ vertically for each 12″ horizontally.
A decorative wood block placed between the vertical casing and the top casing of a unit to provide an elegant interior casing profile.
An aluminum extension pole used to open or close roof windows or awnings which would be inaccessible because of their height.
A high level term used to describe triangles, trapezoids, pentagons, hexagons and octagons.
The first coat of paint in an application that consists of two or more coats; also refers to the paint used for such an initial coat – primer.
Lineal profiles of constant cross section manufactured by combining plastic resin and continuous glass fiber reinforcement. These thermally insulating and structural components are ideally suited for applications where strength, thermal stability and weather resistance are required, such as in patio door frames and commercial windows.
Pyrolytic Low E Glass (Hardcoat)
Pyrolytic Low-E is designed to be used either in non-insulating applications such as energy panels that have exposed surfaces or for insulating glass applications. In some northern climatic situations where an application or customer requires increased solar heat gain, over Low E II performance, this is a desirable option. This increased solar heat gain which is desirable in winter may increase summer energy costs if the home is air conditioned. The pyrolytic coating is typically applied to the second surface, but can be applied to the third surface to provide increased solar heat gain.
The resistance a material has to heat flow. Higher numbers indicate greater insulating capabilities.
A groove along or near the edge of a piece of wood.
The length of an imaginary line from the center point of a circle to the arc or circumference of a circle.
The cross or horizontal members of the framework of a sash, door or other panel assembly.
Kerfs machined into the frame parts of a unit. Relief kerfs inhibit warping.
Refers to units which are sized for replacement purposes.
A circular cover plate attached to the stile directly behind a knob or door handle. May be plain or have a decorative design embossed into the cover.
A term used to describe the steel drive worm, gears and crank device used for opening awnings and casements.
The opening in the wall where a window or door unit is to be installed. Openings are larger than the size of the unit to allow room for insulation and to shim the unit square.
Generally a semicircle window which is mulled to the top of another window or door, thus forming the round top appearance. There are full round tops, separated round tops, ellipticals, transoms, inverted corners, ovals and Gothic heads, etc. Round tops can be used separately or combined with other units to create a seemingly endless selection.
The operating and/or stationary portion of the window unit that is separate from the frame. The sash consists of the following parts:
STILES: Vertical sash members.
RAILS: Horizontal sash members.
CHECK RAILS: Horizontal sash members that meet, as in double hung units. These could also be vertical check stiles, as in the glider or patio door.
BARS: Divisional members extending from rail to rail or from stile to stile in an authentic divided lite unit.
MUNTINS: Divisional members extending from a bar to a rail or stile or another bar.
An optional metal device which attaches to a casement sill and bottom rail which limits the sash to a specified opening -5, 10, 15 or 20 degrees.
A locking device which holds a window shut, such as a lock at the check rails of a double hung unit. Larger units utilize two locks.
Sash Opening (SO)
The opening between wood frame members for both height and width (disregarding any jamb hardware tracks). This measurement is used predominantly when measuring an opening for the Double Hung Tilt Pac.
Horizontal measurement across the face of a sash.
Screen OM (outside measurement)
The width and the height of a screen including wood or metal surrounds.
A close-mesh woven screen material of metal or fiberglass attached to an aluminum or wood surround. Screens inhibit entry of insects, yet permit light, air and vision. Most window and door products utilize full screens. Half-screens are available for single hung units.
The side (vertical) member of a frame.
A stationary glass panel mulled to or installed next to a door.
The horizontal member forming the bottom of a window or exterior door frame; the lowest member of the frame of a structure, resting on the foundation and supporting the frame.
The extension of the lip of a window sill to the outside edge of the casing.
A window very similar to a double hung window, except that the top sash is stationary or non-operable.
Sliding French Door
A sliding door utilizing French door style panels.
The measure of the tilt of a line; rise over run.
An interlocking metal bracket attached at the center of the hinge side of a casement sash and frame with a call number height of 40″ or more and both sides of an Awning sash and frame with a call number height of 48″ or more. It pulls the sash tightly against the frame weather-strip to maximize performance.
Used to separate the two pieces of glass in an insulating glass panel.
For measuring the area of a unit. RO width (in inches) x RO height (in inches) divided by 144 equals the area in square feet of a unit.
A semi-elliptical area, the lower center is the point where the dividing spokes meet and radiate outward. May be constructed of glazed sash, removable grilles, ADL or SDL.
A non-operating sash, panel or unit.
Stationary Sash Bracket
A 90 degree L bracket used to secure stationary casement and awning sash to the frame. The sash can be removed for replacement by removing the wood stops and bracket screws.
The upright or vertical perimeter pieces of a sash, panel or screen.
A horizontal trim member that laps the window sill above the apron and extends beyond the interior casing. See apron entry.
A wood framed assembly containing non-removable glass. The storm sash is removed during the summer and replaced with a wood framed screen.
Structural Masonry Brackets
An installation bracket used with multiple high/wide window units or large doors for added structural support. The brackets are also used to attach the unit in the rough opening in lieu of nailing through the casing, thus eliminating unsightly nail holes.
The supplemental member of a frame used under most awning and casement units as an additional sill with the primary purpose being to hold multiple units together at the sill.
A semi-elliptical area, the lower center of which contains a sun-like figure with sun rays radiating therefrom. May be constructed of glazed sash, removable grilles, ADL or SDL.
An attractive, protective trim which is secured to an energy panel by an adhesive or vinyl barb to give the glass panel a safe finished edge. Also the aluminum framework for most standard screens.
Float glass panels heated and then cooled rapidly in a controlled environment. This process makes the glass several times stronger than regular glass. It also makes it safer because when broken it yields small pebble-like fragments.
A pattern of a window unit from which dimensions and measurements can be determined. Round Tops require templates for replacement units.
Current term referring to any product or unit when three frames (i.e. separate jambs) are mulled together as a multiple unit.
A window above a window or door. Transoms can be either stationary or operating.
A vinyl or aluminum button and screw. Buttons are used to secure wood combinations, storm sash and wood screens to the exterior casing or energy panels to the sash or door panel.
Current term referring to any product or unit when two frames (i.e. separate jambs) are mulled together as a multiple unit.
A measure of total heat flow through a window or door barrier from room air to outside air. Lower numbers indicate greater insulating capabilities.
One single product such as a one wide casement.
Vinyl Glazing Bead
A vinyl extrusion used on clad units which serves the same purpose as a wood glazing bead for wood units.
A strip of resilient material designed to seal the sash and frame members in order to reduce air and water infiltration.
Glass with wire embedded into the glass when the glass is still in a molten state. This prevents the glass from falling out of the sash if it should break.
The letters OX or XO identify the operation of window or door units as viewed from the exterior. The letter O stands for stationary while the letter X stands for operating.