Simpson Door Company

Glossary of Terms

ARGON GAS FILLED: Insulated glazing filled with argon gas to yield superior insulating, energy gain/loss factors.

ARTIST COLLECTION®: Simpson's line of exterior doors that combine the design talents of today's artists with Simpson's manufacturing excellence.

ASTRAGAL: When two doors are installed in a double-hung installation, the vertical profile that divides the two doors, providing a weather seal and place for the strike for the operable door. The astragal is usually attached to the fixed door, but is sometimes removable.

BAR: A narrow, rabbeted, horizontal, vertical or diagonal wood member extending the total length or width of a glazed opening, used to separate individual pieces of glazing material.

BEAD: See glazing bead.

BEVELED EDGE: A shallow angle applied to the perimeter of one side of a piece of glass, usually used on small pieces of glass.

BRICK MOULD: The exterior profile that is used to trim out a door installation around the top and sides of the door(s) and/or sidelight(s).

BUILDER’S ADVANTAGE SERIES®: Simpson’s Builder’s Advantage Series offers large decorative glass units with clean and simple door design. The result is a welcome mix of both traditional and ornamental design philosophies.

BUNGALOW SERIES®: Simpson's line of exterior doors that combine the traditional look of beaded, v-groove panels with glass, creating a traditional look that's popular in today's home architecture.

C-GROOVE: A shallow, wide groove cut in one side of a glass panel, usually in a decorative design, usually polished. Compare to v-groove.

DOOR, COMBINATION: A door assembly of stiles, rails and wood panels utilizing interchangeable insect screening and glazing panel inserts. Combination doors are normally designed to occupy the exterior rabbet of exterior door frames.

DOOR, DECORATIVE: A door assembled of stiles and rails, that typically incorporates a glazed opening and raised moulding in the construction.

DOOR, FRENCH: A door assembly of stiles and rails, containing primarily glass inserts and may possibly contain bars.

DOOR, LOUVER: A door with one or more sets of louvers in place of panels. Simpson Louver doors feature a thick, 2-1/4" plantation-style blade that affords strength and privacy while allowing air flow from room to room.

DOOR, PANEL: A door assembly of stiles, rails and one or more panel modules. Intermediate rails or mullions are used to separate panels.

DOOR, PERFORMANCE SERIES®: A door manufactured for exterior use with composite components constructed into the bottom of the stiles to block moisture absorption into the door. For additional protection, a medium density overlay (MDO) face and PVC sticking can be specified.

DOOR, SASH: A door assembly of stiles, rails and both glass and panel modules.

DOOR, STILE & RAIL: A door assembled of a framework of vertical stile components and horizontal rail components to form openings that are filled with inserts comprised of wood, glass, or other materials.

DOWELED CONSTRUCTION: A method of constructing wood doors where holes are machined into, but not through, the stiles and matching holes in the rails. Dowels are inserted into these holes with glue to attach the rails to the stiles.

DP RATINGS: Design pressure rating that describes a product’s ability to withstand uniform loads caused by wind.

DRIP MOULD: A horizontal moulding section used as a decorative detail on a door, usually applied to the upper intermediate rail of a door.

DUTCH: A door divided horizontally so that the lower or upper part can be shut separately.

EDGE BAND (EDGE STRIP): Applied to both the outside and inside of Simpson stile and rail components. The edge bands cover the fingerjointed core of the component and blend seamlessly with surface veneers.

ENGINEERED CONSTRUCTION: A method of door component construction utilizing smaller fingerjointed, end- glued pieces of core material and a surface veneer yielding a superior component as opposed to the same component made of solid wood. See core.

INSULATED GLAZING (IG): A glazing construction consisting of two or more pieces of glass separated by a sealed, insulating air space(s).

JAMB: The vertical and horizontal frame members, which along with the sill, makes up a door frame.

LAMINATED CONSTRUCTION: A method of bonding multiple layers of wood, solid or composite to form a thicker component.

LEAF: An individual door in a pair or multiple arrangement of doors. See Door, Bifold.

LOW-E: A glazing option made with either a special coating or in combination with a gas fill (see argon filled) meant to reduce energy transmission through the glazing modules.

MASTERMARK® COLLECTION: Simpson’s premier line of exterior doors. When you order a Mastermark door, you are getting the very best design, materials and craftsmanship available in the world today.

MILL OPTION: A door made of available softwood, normally either Douglas Fir or Western Hemlock, at the option of the manufacturing facility.

MORTISE: A square hole or trough cut into a rail or stile meant to receive a tenon for a mortise-and-tenon joint.

MULL COVER: A piece of trim used to conceal the joint between two pieces of jamb.

MULLION (MUTT): A vertical module used to separate panels.

MUNTIN (MUNTIN BAR): A short bar, either horizontal or vertical, used to separate individual pieces of glazing material but which does not extend the full width or length of the opening.

NANTUCKET COLLECTION™: Simpson Nantucket Collection wood doors are an award-winning combination of historic charm and modern technology. Made to endure demanding climates.

OVOLO STICKING: Profile on a door component. Simpson's most requested profile and popular for traditional stile and rail doors for decades.

PANEL, FLAT: A solid, laminated, or engineered panel with a flat face.

PANEL, RAISED: A door panel whose face is raised above the edges, which are shaped to fit into grooves in the stiles and rails. Raised panels may be solid, laminated or engineered.

PATCH: A matching wood piece carefully inserted and glued into the various modules of the door after defective portions have been removed.

PERFORMANCE SERIES®: See Door, Performance Series.


SELECTS SERIES: Simpson’s Selects Series combines two popular door designs with nine distinct glass options, making your home look unique, without breaking the bank.

SHAKER STICKING: Profile of a door component. Provides a clean design aesthetic for doors.

SIDELIGHT(S): An assembly of stiles, rails, panels and one or multiple glazing module(s). Sidelights are normally designed to occupy a fixed position adjacent to exterior doors, either in a common frame with the door or in a separate frame.

SIMULATED DIVIDED LITE (SDL): A type of construction used in a French or sash door that features a single glass unit with bars applied to the glass surface, providing the look of traditional True Divided Lite with improved performance.

SOLAR HEAT GAIN COEFFICIENT (SHGC): Measures how well a product blocks heat by sunlight. SHGC is expressed as a number between 0 and 1. The lower the SHGC, the less solar heat is transmitted.

SOLID CONSTRUCTION: A method of manufacturing modules or door components from a single piece of raw lumber.

SPECIES: A distinct, scientific designation given to identify various living orders. In our case, species refers to the distinct wood species used in our product, such as Douglas Fir or Western Hemlock.

STANDARD GRADE: Wood products that are structurally sound with minor surface defects and discoloration permitted, providing a surface suitable for an opaque (stain or paint) finish.

STICKING: A profile machined into the edges of stiles, rails, mullions, muntins or bars, adjacent to panels or glazing materials. Simpson's most popular include ovolo sticking and shaker sticking.

STILE: Wooden modules that form the vertical edges of the door; two per door.

CAME: The dividing metal used between small pieces of glass to make a larger glazing panel, sometimes referred to as “leading,” which is often offered in brass, black and silver colors.

CARVING: A decorative design carved or routed into one or more surfaces or faces of a door.

CASING: Interior or exterior trim designed to conceal the joint or gap between two components.

CERAMIC FRIT: A material made of ground glass that is applied to a glass panel in a slurry, and then fired in a furnace to impart a decorative motif.

COMMODITY DOOR: A door layout that is commonly used throughout the industry.

COPED CONSTRUCTION: The ends of rails, mullions, muntins or bars so machined that they will fit and cover the contour of the sticking or other components.

CORE: The innermost layer in veneered construction, normally consisting of several individual wood pieces edge- glued and end-glued or fingerjointed together.

CRAFTSMAN COLLECTION: Simpson's line of exterior doors that combine tall, flat panels with decorative glass designs, a look suitable for any home.

DENTIL SHELF: A horizontal profile that incorporates square “teeth.” A design usually applied to the upper intermediate rail of a door. Also referred to as dentil mould.

DESSICANT: A moisture absorbing additive to the air space in an insulated glass unit to prevent moisture from fogging on the interior surface of the glazing.

DOOR, BIFOLD: Doors so hinged that as to fold flat against the vertical door jamb. Bifold doors are normally classified as either two or four leaf units.

FACE WIDTH: The total width of a door module, minus the width of the part profile and applicable moulding.

FILM-PROTECTED GLASS: A protective film coating applied to protect the glazing from damage due to handling and finishing.

FINGER-JOINT: A series of “fingers” precision machined on the ends of two pieces of wood, which are meshed and bonded tightly together. See core.

FINISH: A protective product applied to the surface of a door, either in the form of a clear material such as varnish or stain-sealer, or as an opaque finish such as paint.

FIRE-RATED DOOR: An exterior-grade door, constructed with panels containing an inner core of fire-abatement material to slow or stop the progress of fire between structures, such as between a garage and a house.

GLAZING: The glass insert(s) or glass modules used in a door.

GLAZING BEAD: A small wood moulding applied to the perimeter of glazed openings to secure the glazing materials within the door.

GLAZING COMPOUND: An extruded bead of synthetic material used to impart water or weather resistant qualities to the glazing of the door.

GLAZING, DECORATIVE: A decorative insert panel made by assembling small pieces of textured or beveled glass to form a pattern divided by came. See came.

GLAZING TAPE: An adhesive, foam tape used to secure a glazed insert in a door, between the applied or stop moulding and the insert.

HEADER: The upper portion of a door opening.

INNERBOND®PANEL: A raised panel made by utilizing laminated construction, yielding a superior panel, resistant to splitting.

PREFIT: The trimming of a door at the factory to fit an exact opening.

PRIMED: A sealing finish applied to a wood door to assist in adherence of the finish paint coat.

RAIL: A horizontal structural module of a door.

RAIL, BOTTOM: The bottom rail of a door.

RAIL, INTERMEDIATE: A rail, other than the top or bottom rail, used to separate panels, or to separate panels from the glazing.

RAIL, LOCK: An intermediate rail, if present, located approximately adjacent to the lock set.

RAIL, TOP: The uppermost rail of a door.

RAISED MOULDING: A decorative profile that extends above the surface of the door that can be either decorative, or can function as a stop for a glass or panel insert.

REDI-PRIME™: Simpson's line of primed interior wood doors. A variety of panel and French designs with a superior surface that is ready to paint.

RESIN PANELS: Panels made with translucent resins and encapsulated materials.

SAFETY GLASS: Glazing materials so constructed, treated or combined with other materials as to minimize the likelihood of cutting or piercing injuries resulting from human contact. Laminated glass, tempered glass, wired glass and safety glass are examples of safety glazing materials used in doors.

SELECT GRADE: Wood products that contain no knots or pitch pockets and have tightly spaced grain, intended to receive a stain or natural finish, free of surface defects that would affect the finish.

STOP: A profile used to secure an insert into a door frame or transom sash.

SWEEP: That portion of the weather-seal attached to the bottom of the door, providing a seal between the door and the sill.

TRANSOM: An assembly of a wood frame and one or more inserts, designed to be installed above a door or door unit, either in a common frame or in a separate frame.

TRUE DIVIDED LITE (TDL): A type of construction used in a French or sash door that features individual glass units divided by muntin bars.

ULTRABLOCK®: TECHNOLOGY A method of door construction that minimizes the natural paths for moisture infiltration in the bottom rail and lower portion of the door stiles and rails, thereby eliminating damage caused by moisture. UltraBlock technology is part of the Performance Series.

U-VALUE (U-FACTOR): The U-value of glass is measured by the number of BTUs that will pass through each square foot area, per degree of temperature difference, from one side of the glass to the other. The lower the U-value, the greater the glass’s resistance to heat flow and the higher the insulating value.

V-GROOVE: A narrow, polished, v-shaped groove cut in one side of a glass or wood panel, usually in a decorative design. Compare to c-groove.

VARNISH: A clear finish that allows the natural colors and figure of the wood to show through the finish. See finish. Compare to paint.

VERTICAL GRAIN: Straight, closely-spaced annual growth rings of light and dark wood made by slicing the wood from cants, as opposed to rotary cutting which produces a wavy figure.

VIEWSAVER®: Simpson’s ViewSaver technology combines a sleek profile bar design with ¾" thick insulated glass for maximum energy efficiency.

WARP: Any distortion in the plane of the door itself and its relationship to the frame or jamb in which it is hung.

WATERBARRIER® TECHNOLOGY: A Simpson manufacturing process that combines a one-piece Medium Density Overlay (MDO) over the face of a door and PVC beads and bars to create an exterior that resists water infiltration. Perfect for extreme exposures to the elements, WaterBarrier technology is part of the Performance Series.

WEATHER SEAL™: A process wherein the profiled end of the bottom rail and profiled side of the stile is coated to resist water infiltration where these two components meet. This process is exclusive to Simpson’s Performance Series.

WOOD COMPOSITE: A wood-based compound utilizing wood fibers, reconstituted wood or other wood derivatives and binder materials.