APRON Interior flat trim piece which is used under the stool at the bottom of the window.
AWNING WINDOW A projecting window, hinged at the top, opening up and out like an awning.
BACK BEDDING The process of adhering and sealing.
CASEMENT WINDOW A projecting window hinged at the sides and usually opening outward like a door.
FLASHING A metal or plastic strip attached to the outside of the side jambs and head to provide a weather barrier, preventing leakage between the window frame and wall.
FRAME Outside members of a window unit which enclose the sashes. Composed of side jambs, head jamb and sill.
GLAZING The glass panes or lights in the sash of a window. Also the act of installing lights of glass in a window sash.
GLAZING BEAD A vinyl or wood strip, applied around the perimeter of the glass on the exterior of the window sash, for holding the glass in place.
GRILLES-BETWEEN-THE GLASS Aluminum bars in varying thicknesses and profiles sealed between insulating glass panels to simulate muntin bars.
HEADER A beam across the top of the rough opening for a window or door. Headers rest on jack studs and support the weight of the wall above the window unit. They are often constructed out of doubled 2x6’s, 2x10’s or 2x12’s.
INSULATING GLASS Two sheets of glass bonded together in a unit to enclose a captive air space. Units are constructed with a metal spacer inside the outer perimeter. The outer edges are sealed. Spacers contain desiccant material for absorbing and holding any remaining moisture in the air space.
JACK STUD Vertical framing members, generally 2x4’s, which form the inside of the window or door rough opening. They support the header and run down to the sole plate.
JAMBS Side jambs are the vertical pieces of a window frame. The head jamb is the horizontal piece across the top.
KEEPER The receiving portion of a lock that interlocks with the lock arm. It’s mounted to the upper sash check rail on a double hung or single hung window and the inside surface of the sash stile on a casement window.
LIFT A handle or grip installed or routed into the bottom rail of the lower sash of a single hung window, making it easier to raise and lower the bottom sash.
MULLION The vertical or horizontal divisions or joints between individual windows in a multiple window unit.
NAILING FIN A vinyl or metal flange integrated into (or attached to) the perimeter of a window frame for installation onto the rough opening’s header, jack studs and rough sill. A continuous nailing fin may surround the frame as with an all-vinyl window or a nailing fin may be affixed to the head and side jambs as with a vinyl clad window frame.
OPERATOR A metal arm and gear device which allows for easy opening and closing of projecting windows; e.g. casement and awning windows.
PICTURE FRAME CASING The use of casing on all four sides of the interior of a window. The stool and apron at the sill are replaced with casing.
PICTURE WINDOW A large stationary (non-ventilating) window which is designed for a maximum view without obstruction.
RAILS The horizontal top and bottom pieces of a window sash or door panel.
ROUGH OPENING The opening built into a frame wall to receive a window or door unit. It is formed with a header along the top that’s supported by jack studs on each side. The rough sill at the bottom is supported by cripples. A rough opening is generally greater in width and height than the window or door unit.
ROUGH SILL The horizontal framing piece, usually a 2x4, which forms the bottom of the rough opening. It is toe-nailed into the jack studs and supported by cripples.
SASH The framework holding the glass in a window unit. It’s composed of two stiles (sides) and two rails (top and bottom).
SASH BALANCE A coiled spring or spiral system integrated into the jamb liners to allow double hung or single hung sashes to open and close. They also allow the sashes to remain open in varied positions.
SASH LOCK Generally, a cam-action lock applied to the check rails of a double/single hung window, or sliding window to pull the check rails tightly together. They are also applied to the open edges of a projecting window to seal the sash tightly to the frame. Sash locks provide security and weatherability.
SEAT BOARD A flat board cut to fit the contour of a bow or bay window that’s installed between the sills and the flat wall surface. They provide a seat or shelf space.
SHIMS Wood wedges used to secure the window or door unit in the rough or masonry opening in a square, level and plumb position during and after installation.
SIDE LIGHTS Tall, narrow, fixed or operating sash on either or both sides of a door to light an entryway or vestibule.
SILL The horizontal piece that forms the bottom of a window frame. It is generally slanted down to the outside to shed standing water.
SOLE PLATE The bottom horizontal piece in a frame wall, usually single or double 2x4’s. The wall is nailed into the deck or rough floor through the sole plate.
SLIDING WINDOW A window with two or more sashes that slide horizontally past each other within the frame.
STILE The vertical side pieces of a window sash or door panel.
STOOL The interior horizontal trim piece at the bottom of the window frame. The shelf-like piece that projects into the room.
