Alpine Stairway – a stairway characterized by open risers and thick stringers.

Angle Newel – see Intersection Newel.

Appliqué – an ornamental trim element, which may be applied to stringers, risers, fascia, or box newels.

Apron – see Stringer.

Apron Lining – see Stringer, see Ornamental Stringer.

Astragal Moulding – a narrow, convex, architectural moulding which is often used on a self-supporting stairway at the point where the drywall meets the edge of the stairway’s stringer.

Baluster – a vertical member spanning from the stairway’s tread, floating shoe rail, shoe rail, buttress cap board or the landing’s landing tread to the handrail above. Balusters serve function and aesthetics.

Balustrade – a collective term, which references newel posts, balusters, handrail and fittings as an assembly.

Baseboard – that horizontally applied trim member that is positioned flat against a wall finishing the meeting point of the wall and the floor.

Baseboard Block – a preparation to the bottom edge of the lower end of a stairway stringer that is designed as a termination point for the baseboard.

Block-Top Baluster – a baluster with a square top designed to be inserted into a railing whose bottom surface is mortised.

Box Newel Cap – an ornamental cap or finial applied to the top of a box newel.

Box Newel Post – a hollow constructed newel post, usually square, that is fabricated utilizing conventional woodworking methods rather than turned on a lathe.

Box Stairway – a stairway from that category of construction that utilizes box stringers, usually intended for applications between walls.

Box Stairway Buttress – a form of foundation for an open balustrade on a box stairway, which includes a knee wall or structural carrier supporting the side of the box stairway that is to be fitted with the open balustrade.

Box Stringer – a stringer that is mortised to house the ends of the stairway’s treads and risers that are wedged into the mortises with tapered, glue-smeared wedges.

Box Width – the overall width, outside of stringer to outside of stringer, of a box stairway.

Bracket – see Stringer Bracket, Handrail Bracket.

Bracket Stairway – an open stairway with flat scrolled ornamental brackets applied to the open stringer.

Bull Nosed Starting Step – one that has, in the plan view, a half circle shape that protrudes beyond the stairway’s stringer.

Bull Nosed Tread – one whose leading edge is a half circle shape.

Buttress – see Box Stairway Buttress; see Landing Buttress.

Buttress Cap Board – a finish covering board, usually with molded edges, applied to the topside of a stairway or landing buttress.

Buttress Design Landing Trim Package – a trim package which includes the fascia, baseboard, buttress cap-board, and Mouldings required to trim a given buttress landing.

Cap – see Box Newel Cap; see Buttress Cap Board; see Parapet Cap Board; see Rail fitting Cap.

Cap Board – see Buttress Cap Board; see Parapet Cap Board.

Capping – see Buttress Cap Board; see Parapet Cap.

Carriages – see Carrier.

Carrier – a structural element, usually wood or steel, applied to the underside of a stairway to cause its independence.

Category of a Stairway – see Stairway Category.

Circle – a plane figure generated around a center work point. A circle contains 360°

Circular Stairway – describes a stairway from a group comprised of both curved and spiral stairways.

Closed Stairway – see Box Stairway.

Combination Alignment – a condition in which both the lower detail elements of the stairway balusters are aligned in the horizontal plane, and their upper detail elements are aligned along the rake angle.

Combination Stairway – a stairway whose construction is partially from each of the two categories (box and open) of construction.

Commode Step – describes a series of two or more bullnosed ended (in the plan view) tread and riser assemblies stacked on top of one another forming a layered starting step assembly or stairway.

Concave Tread – a tread whose leading edge, trailing edge, or both edges is convex in shape, as viewed from the bottom of the stairway.

Configuration of a Stairway – see Stairway Configuration.

Conventional Design Landing Trim Package – a standard landing trim package, which includes landing tread, fascia, and scotia.

Convex Tread – a tread whose leading edge, trailing edge, or both edges is concave in shape, as viewed from the bottom of the stairway.

Cove Moulding – a Moulding from the scotia-Moulding group. See Scotia.

Cross Flight – see Side Flight.

Curb – the superstructure of that portion of a landing buttress that is elevated above the floor surface that the buttress is servicing.

Curtain Step – see Scroll Step.

Curved Stairway – a stairway from the circular stairway class that includes at least one curved or radius stairway stringer.

Cut – see Tread Run.

Cut String – see Open Stringer.

Dependent Buttress – a buttress design that includes the employment of a supporting wall from below or a structural carrier to cause the buttress’ independence.

Dogleg Stairway – see Switchback Stairway.

Double Newel – a collective term describing two side-byside newel posts, usually utilized in open-welled half-turn stairways.

Drop – see Newel Drop.

Easing – see Overhand Easing; see Starting Easing; see Starting Easing Cap; see Up easing.

Elevation View – the viewpoint depicting vertical ascent from one direction.

Elliptical Stairway – a curved stairway designed with compound radii.

Encroachment – see Stairwell Encroachment.

Faired – a methodical fabrication or design term that describes the blending of compound radii, or angular pieces, to present a graceful flow to the millwork.

Fascia Board – a horizontal trim board which covers framing members to achieve a finished appearance.

Fascia Trim – a collective term referencing a landing’s complete trim package, exclusive of its balustrade.

FFD – Finished floor down – refers to the thickness of the finish flooring material intended for application atop the sub floor; a critical element of the riser calculation.

FFU – Finished floor up – refers to the thickness of the finish flooring material intended for application atop the sub floor; a critical element of the riser calculation.

Fillet – is used to fill the plow between the balusters after they are installed in both a handrail or shoerail.

Finial – an ornamental top for use on a newel post. A finial may be a ball, a pineapple, a spire or any other decorative ornament.

Fitting – a generic term describing any of the fittings utilized in the design of a balustrade’s handrail or a wall rail or a safety rail.

Flared Stairway – describes that stairway type that is designed with flared stairway treads; an inline-flared stairway may have a concave radius dissected through one or both ends of its treads; a radial flared stairway may have a concave radius dissecting one of both ends of its treads.

Flier – see Flyer.

Flight – any individual stairway section. A flight may be two risers or twenty risers or more. Individual flights are commonly joined with intermediate landings, but may span directly from one floor to another of a building.

Flight of Stairs – see Flight.

Floating Stairway – a stringer-less stairway whose treads emerge from a stairwell wall, apparently unsupported.

Flush Mount/Flush Mounting a Newel Post – the method of mounting a newel flush on a starting step, tread, landing or balcony.

Flyer – see Inline Tread – that stairway, or stairway tread, which is parallel in design.

Free Form Tread – a tread whose shape cannot be accurately described by geometric terminology.

Freestanding Stairway – see Independent Stairway.

Glue Block – a small, usually triangular, block of wood that is coated with glue and strategically utilized to bond two stairway components, such as tread and riser.

Going – see Tread, see Run, see Stairway Run.

Going of a Flight – see Stairway Run.

Grand Stairway – an elaborately designed stairway, generally found in the entrance foyer of a larger home.

Gooseneck – a generic term for that group of rail fittings comprising intersection and transition goosenecks from both the PTP (post to post) and OTP (over the post) categories.

Half Pace Landing – an intermediate landing servicing a primary stairway flight along with two additional side flights.

Half Turn Stairway – a stairway flight, or flights, that terminates in a direction that is approximately 180° from it’s beginning.

Hand of Stair (the) – describes the open side or turning direction of a stairway as viewed from the bottom.

Handrail – the top element of a balustrade, which serves as a safety implement to hold while traversing a stairway. A wall-mounted element serving the same purpose.

Handrail Bracket – an ornamental and functional apparatus used to fasten a handrail to a wall. Handrail brackets may be fabricated from wood, metal or other material.

Header – one of the series of beams defining the perimeter of a stairwell opening.

Header Joist – the framing member utilized as a stairway header, which relates to the width of a stairwell.

Headroom – describes the dimensional attribute relating to the vertical distance between the stairway’s rake line and the nearest appurtenance overhead.

Helical Stairway – a stairway that climbs symmetrically around a cylinder, real or imaginary. A spiral stairway is a classic helical stairway.

Horizontal Alignment – a condition in which the bottom detail elements of the stairway balusters are aligned in the horizontal plane.

Horizontal Baluster – a baluster maintaining strict horizontal alignment of a given baluster’s bottom block. See Raking Baluster.

Horn – see Stringer Horn.

Horse – see Stringer.

Housed – a woodworking term that describes one stairway or balustrade component that is let into a second component.

Housed Stringer – see Box Stringer.

Independent Buttress – a stairway buttress which is not supported by a knee wall from below, rather, the stairway itself is fabricated as a self-supporting assembly or it’s independence is achieved with the assistance of a structural carrier applied against or under the stairway.

Independent Stairway – a stairway which is not supported by a knee wall from below, rather, the stairway itself is fabricated as a self-supporting assembly or its independence is achieved with the assistance of a structural carrier applied against or under the stairway.

In-line Flared Tread – describes a stairway tread type that is rectangular with a concave radius dissecting one or both ends of the tread.

In-line Stairway – describes a stairway type designed with parallel rectangular stairway treads. An in-line stairway is also referred to as a flyer.

Intermediate Landing – a landing that is situated as a point of convergence for two or more stairway flights. An intermediate landing may be an appurtenance to a level of the building in a split-level building design.

Intersection Fitting – a railing element which connects the railing sections at the intersection of two stairway flights.

Intersection Newel – a type of newel that is positioned at the intersection of two converging stairways.

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Knee Wall – an angled wall built either to the underside of a stairway or flush with the top (rake line) edge of a box stairway. A knee wall serves as a structural support. It may also server as a means of closing off a stairway below.

Landing – a beginning or termination point for a stairway flight. A landing may be a primary level of the building or an intermediate fabrication. See Intermediate Landing.

Landing Area – describes that area adjacent to the stairway at either its commencement or termination point at a primary level of the building.

Landing Baluster – a baluster positioned on a level landing.

Landing Buttress – describes a built-up curb applied to the leading edge of a landing’s surface that serves as the foundation for the landing’s balustrade.

Landing Fitting – a railing element used to connect together horizontal sections of railing on a landing.

Landing Newel – a type of newel that is positioned at any point along a landing, either intermediate or primary, that does not transition directly into a stairway balustrade or wall rail. The top of the stairway newel is referred to as a transition newel rather than a landing newel.

Landing Transition Baluster – a baluster positioned at the point at which a stairway joins a landing.

Landing Tread – the narrow transition tread incorporated into the top of a stairway flight. The top surface of the landing tread aligns flush with the top surface of the landing’s finish flooring material.

Landing Trim – the landing tread, fascia, and Moulding surrounding a landing, and providing a finished appearance.

Left Hand – describes the open side of an open stairway or the side of a box stairway, while ascending, that is to be finished with a buttress.

Level – horizontal. (not to be confused with plumb, which refers to vertically true).

Level Quarter Turn – a quarter turn designed for use in horizontal applications.

Level Rail – refers to that rail found in a landing balustrade or a wall rail passing around the perimeter of a landing.

Line of Travel – see Walking Line.

Long Base Baluster – a baluster whose base is elongated in order to facilitate rake alignment on the stairway.

Mitered Stringer – see Open Stringer.

Model of a Stairway – see Stairway Model

Moulding – a broad term describing lineal trim elements available in numerous shapes and sizes.

Monkey Tail – a colloquial term that refers to the turnout configuration of starting fitting. See Turnout.

Mortised – a woodworking term relating to letting a groove or series of grooves into a component by skillfully removing wood to a defined configuration.

Mounting Bracket – see Handrail Bracket

Newel Cap – an ornamental cap affixed to the top of a newel post, usually a box newel post. A newel cap may be further decorated by adding a finial atop of the cap itself.

Newel Drop – an ornamental cap or other finial, or a combination of cap and finial, applied to the bottom of a newel post.

Newel Post – a larger structural post, usually positioned at the stairway’s beginning, the intersection of two stairway flights, the transition of a stairway and a landing or at strategic points around the landing.

Newel Stairway – a stairway that employs the use of newel posts within its balustrade.

Nominal Size – refers to the reference size which is greater than the actual size, i.e. a 2″ x 4″ as referenced is actually 1 1/2″ x 3 1/2″.

Nosing – 1) that portion of a stairway tread that overhangs the riser board. 2) A narrow trim piece that simulates a tread’s nosing. Landing tread is not nosing. See Return Nosing.

Notch/Newel Notch – a cut is made in the bottom block of a newel post to allow the newel to overhang the edge of a tread/riser, landing or balcony.

Open Left Stairway – a stairway from that category ofconstruction that utilizes an open stringer on its left hand side while ascending.

Open Newel Stairway – an open stairway, incorporating newel posts as a design element of its balustrade.

Open Right Stairway – a stairway from that category of construction that utilizes an open stringer on its right hand side while ascending.

Open Riser – the omission of, or reduction in height, of a riser board, giving the stairway a “see-through” appearance.

Open Stairway – a stairway from that category of construction that utilizes one or more open stringer. An open stairway is usually fitted with an open balustrade.

Open String – see Open Stringer.

Open Stringer – a stairway stringer that is either cut out or is fitted with blocking, yielding horizontal surfaces to receive stairway treads and usually vertical surfaces to receive riser boards.

Opening Cap – an end cap fitting utilized in an over-the-post balustrade as a termination means for an independent balustrade.

Open-Well(ed) – describes a stairwell that is larger than its stairway configuration in the plan view, usually granting line of sight from floor to floor.

Ornamental Enhancement Package – describes the trim elements included with a particular stairway, buttress or landing trim model.

Ornamental Stringer – that false stairway stringer applied to a stairway buttress as an ornamental element intended to appear as though it is an actual stairway stringer of box construction.

Over the Post – refers to a configuration class of newel post or balustrade where the top handrail passes over the top of the balustrade’s newel posts.

Overhand Easing – that radius handrail fitting that transitions a rake-angle stairway rail to a horizontal plane.

Over-the-Post Balustrade – that balustrade employing the use of over-the-post newel posts.

Panel Nosing – a type of ornamental Moulding, which has the effect of dividing a wall, stringer, riser, or fascia board into panels.

Parapet Cap Board – a cap board designed for application atop a parapet wall.

Parapet Wall – a wall built up, on either a rake line or horizontal plane, to an elevation sufficient for its service as a protective guard on either a box stairway or landing.

Picket – see Baluster.

Pitch – see Rake Angle.

Pitch Rail – see Stair Rail.

Plain Square Baluster – see Square Baluster.

Plan View – describes the view of an object from directly above, i.e. a floor plan is a classic plan view.

Plan View Layout – describes the configuration of a design in the plan view.

Platform – see Landing. See Intermediate Landing.

Plinth – a trim block, usually square or rectangular, utilized as a transition means for two dissimilar Mouldings, or for two boards converging on acutely different planes.

Plow – a groove let into an element of a stairway or its balustrade, usually handrail, sub rail shoe rail or a buttress cap board.

Plumb – vertical. (not to be confused with level, which refers to horizontally true).

Post to Post – refers to a configuration class of newel post or balustrade where the top handrail abuts the face of the balustrade’s newel post.

Post-to-Post Balustrade – that balustrade employing the use of post-to-post newel posts.

Quarter Landing – a square or nearly square landing at the convergence point of two stairway flights or one stairway flight and another landing or landing area.

Quarter Space of Winders – refers to the turning point of a stairway, approximating 90°, which is comprised of a number of winder treads.

Quarter Turn Stairway – a stairway so configured that its direction of travel turns approximately 90° adjacent to its beginning point.

Radial Flared Tread – a radial stairway tread with a concave radius dissecting through one or both of its ends.

Radial Tread – a stairway tread whose leading and trailing edges radiate from a radius point located outside the quadrant of the stairway.

Radius – one half the diameter of a circle. See Circle.

Rail – see Handrail. See Shoe Rail. See Sub Rail.

Rail Bolt – a fastening device designed as a lag screw on one end while the opposite end is machine thread with a nut and washer. A rail bolt is used to fasten handrail to fittings and newel posts.

Rail Fitting – any one of that group of fittings intended for fastening to a handrail of matching profile while transitioning the handrail’s direction or termination.

Rail Fitting Cap – the enlarged portion of any over the post rail fitting that is positioned directly atop the newel post.

Rake – see Rake Angle.

Rake Angle – refers to the angle of inclination of a stairway, balustrade or wall rail. It may be stated as rise over run or as a number of degrees of inclination.

Rake Line – the reference line defining the rake angle.

Rake-line Angle Alignment – a condition in which both the top and bottom detail elements of stairway balusters are aligned parallel to the rake line.

Raking Baluster – a baluster maintaining strict rake line alignment of all descriptive elements of a given baluster, including top and bottom blocks. See Horizontal Baluster.

Ramp – see Up Easing.

Return Balustrade – the section of a landing balustrade fastened to a wall on the landing.

Return Flight – a tread whose nosing is mitered and returned along the end of the tread, covering otherwise exposed end grain, and providing a finished appearance. Also see Side Flight.

Reverse Flight – a stairway flight travelling in a direction that is approximately 180° to an adjacent primary flight.

Rise – see Riser Height. See Total Rise.

Riser – describes a unit of measure for a stairway relating to one tread and riser assembly, i.e. a stairway with eighteen risers.

Riser Block – see Glue Block.

Return Nosed Tread – a stairway tread finished with a return nosing on one or both ends. Return nosed treads are utilized in open stairway construction.

Return Nosing – a finished decorative cap applied to the open end of a stairway tread. A return nosing is mitered into the tread’s nosing while the trailing end is returned on itself.

Riser Board – that component of stairway, either box or open construction, that connects the trailing edge of a subordinate tread to the underside of a successive tread.

Riser Height – the vertical dimensional attribute of a riser, measured from the top surface of one stairway tread to the top surface of the next.

Rosette – an ornamental termination plaque, usually round, oval or rectangular, for a handrail.

Routed Out – see Mortised.

Routed Stringer – see Box Stringer.

Run – see Tread Run; see Stairway Run.

Safety Rail – a secondary handrail that is affixed to the inner side of a stairway’s balustrade, usually in a commercial setting, where that stairway balustrade is too high for children to utilize.

Scotia – any of the decorative Mouldings applied to the underside of a tread’s nosing, a landing tread’s nosing or panel nosing stock.

Scroll Step – a term applied to a starting step so designed, as to agree in part, in the plan view, with the handrail’s starting fitting configuration mounted directly above.

Self-Supporting Stairway – see Independent Stairway.

Setback – a dimensional reference term relating to the distance between a stairway’s beginning and adjacent appurtenances.

Shoe Moulding – a small decorative Moulding applied around the perimeter of a stairway starting step riser to conceal the junction of that riser and the finish flooring.

ShoeRail – a decorative and functional trim piece into which the bottom baluster blocks mount. A shoe rail is typically included in a buttress design but may be utilized as a floating shoe rail in other applications as well.

Short Wall – see Knee Wall

Side Flight – a third stairway flight commencing at the intermediate landing of a stairway whose configuration would otherwise be classified as quarter-turn or half-turn.

Soffit of a Stair – describes the finish to the underside of a stairway flight.

Spandrel – that more or less triangular space between a stairway’s underside and the floor surface below the
stairway.

Special Application Stairway (SAS) – a stairway from the sub-classification group defining those inordinately oversized or uniquely shaped stairways, usually servicing a lowered or elevated room within the building. An SAS stairway is seldom more than three or four risers.

Specifications – a full set of instructions detailing all of the particular elements of a stairway and its related balustrade and handrails. A collective term, which includes material species and dimensional attributes of a stairway and its balustrade, and its related trim, along with particulars describing the system’s design, and perhaps, model.

Spindle – see Baluster

Spiral Stairway – a stairway type whose radial treads radiate from a center column. The outer perimeter of a spiral stairway is usually circular, however it may be octagonal, square or other shape.

Splayed Tread – a stairway tread of the inline type, with one or both ends cut at less than 90° from the treads nosing, causing the tread to widen at its beginning. Do not confuse a splayed tread with a flared tread.

Square Baluster – a baluster whose cross section, at any point along its length, is square in shape.

Square Step – see Inline Tread.

Stair Direction – see Stairway Configuration.

Stair Pitch – see Rake Angle. See Rake Line.

Stair Rail – the uppermost part of a balustrade which is grasped when ascending or descending a stairway.

Stair Ratio – see Stairway Rise/Run Formula.

Staircase – see Stairway.

Stairs – see Stairway.

Stairway – 1) one or more flights within a stairwell that ascend from one primary level of a building to another. 2) An individual flight. 3) An entire stairway along with its balustrade may simply be referred to as a stairway.

Stairway Category – describes the class of a stairway’s construction, which is either box construction or open construction.

Stairway Configuration – describes an entire stairway’s direction of travel in the plan view. Common stairway configurations are straight and turning, with turning stairways described by their degree of turn in eighths or quarters.

Stairway Drum – a special starting step design in which a drum-shaped detail is incorporated into the bottom end of a box stringer, and secured to the top surface of the starting step’s tread.

Stairway Model – denotes, by name, a stairway consisting of specific elements of ornamental enhancement.

Stairway Rise/Run Formula – terminology describing the dimensional relationship between a stairway’s tread run and its riser height.

Stairway Run – a dimensional term referencing the overall horizontal length of a stairway from the back surface of the stairway’s top riser board to the leading edge of the tread’s nosing of the stairway’s bottom tread, as the stairway is viewed in plan.

Stairway Starting Baluster – a baluster positioned under a starting fitting such as a turnout or volute.

Stairway Style – describes the general architectural styling of the stairway as either traditional or contemporary.

Stairway Transition Baluster – a baluster which is positioned under easings.

Stairway Tread Baluster – a baluster positioned on the surface of a stairway tread.

Stairway Width – a dimensional term referencing the width of a stairway as measured from the outside surfaces of the stairway’s stringer.

Stairwell – that opening through which a stairway passes.

Stairwell Encroachment – interference within the proportions of the stairwell that impacts the stairway’s sizing.

Stairwell Run – a dimensional term referencing the length of the stairwell, which is usually its greater dimension.

Stairwell Width – a dimensional term referencing the width of a stairwell, which is usually its lesser dimension, but always that dimension perpendicular to the stairwell’s run.

Standard Tread – that stairway tread type classified as “inline” and intended for use in box stairway construction.

Starting Easing – a term assigned to that group of rail fittings that, in elevation, begin on a horizontal plane transitioning with a radius into a rake line ascent.

Starting Easing Cap – a starting easing fitting beginning with a horizontal cap, usually round, octagonal or square, intended for positioning on top of a starting newel post in an over the post balustrade.

Starting Fitting – a railing element used at the base of a stairway, which connects to a subsequent fitting or handrail section ascending the stairway.

Starting Newel – the newel post utilized to begin the stairway’s balustrade, which always begins at the bottom end of the stairway.

Starting Step – the tread element of a starting step unit.

Starting Step Unit – a collective term referencing all of the elements included with a stating step. Those elements may include a riser board assembly, Mouldings and other elements of ornamental enhancement, in addition to a tread.

Step – see Tread.

Stepped Baluster – see Horizontal Baluster.

Stile – the vertical element in a raised or recessed panel.

Straight Stairway – one whose direction of travel is straight ahead versus a turning stairway whose direction of travel changes.

Stringer – the element of a stairway that joins the tread and riser assemblies together uniting them into the stairway.

Stringer Bracket – a flat, usually scrolled, decorative element that is affixed to an open stringer at the underside of the tread return nosing, designed to appear as though bracket to bracket is a continuous assembly.

Stringer Horn – that top or bottom portion of a box stairway stringer that transitions into the baseboard.

Stringer Over Stringer – a term that describes the vertical stacking of two stairway stringers rising in directions opposite to one another, as found in a switchback stairway.

Stringless Stairway – see Floating Stairway.

Style of a Stairway – see Stairway Style.

Sub Rail – in essence, a second handrail, usually of square or rectangular design that is let into a mortise in the underside of the primary handrail. The sub rail adds an additional element to the design and serves as a termination facility for the balustrade’s balusters.

Switchback Stairway – a stairway comprising two or more flights, ascending in opposite directions with the nearer stringer of each stairway flight vertically stacked or aligned, yielding a common spandrel.

Tandem Cap – a term describing a handrail fitting from the landing fitting group of over-the-post fittings whose function is to transition the handrail of an over-the-post landing balustrade over the top of an intermediate landing newel post.

Tapered Baluster – a baluster whose top and bottom cross-section sizes differ, and transitions along its length on an angle, from one end to the other.

Total Rise – that vertical dimension encompassing the entire elevation that a stairway is to ascend.

Total Run – that horizontal dimension encompassing the entire horizontal length of a stairway in the plan view….therefore, total run includes the sum of the incremental tread runs plus factors for tread nosing and riser board, which are additional to the sum total of tread runs.

Transition Fitting – a railing element used to transition the railing from a stairway to a level landing.

Tread – that element of a stairway upon which one steps.

Tread Cover – a temporary, protective covering affixed to a stairway’s treads to shield them from damage during the building’s construction.

Tread Run – a dimensional term referencing the horizontal distance from the face of one riser board to the face of the subsequent riser board. Tread run is exclusive of the tread’s nosing which is usually 1 ¼”.

Tread Support – an appurtenance whose function is to prevent tread deflection.

Tread Width – the overall usable width of a stairway’s tread as measured either between a pair of box stringers or to the tip of the return nosing in an open stairway.

Trimmer Joist – the framing member utilized as a stairwell trimmer that relates to the run on a stairway.

Turning Stairway – one whose direction of travel turns, versus a straight stairway whose direction of travel remains straight.

Turnout – a horizontal starting fitting from the over-thepost group of rail fittings that begins to radius outward off the centerline of the stairway’s balustrade, usually used with a starting step unit whose shape agrees, in part, in the plan view with that of the turnout.

Unit Rise – see Riser Height.

Unit Run – see Tread Run.

Up Easing – a term assigned to the rail fitting that, in elevation, begins on a horizontal plane transitioning with a radius into a rake line ascent.

Upper Construction – refers to that portion of a stairway’s construction that is visible after the completion of the building.

Upper Termination Point – references that point where the top of the stairway adjoins the upper landing.

Volute – a horizontally circular scrolled starting fitting from the over-the-post group of rail fittings usually used with a starting step unit whose shape agrees, in the plan view, with that of the volute.

Walking Line – refers to the line of ascent of a stairway, which is determined to be a certain distance into the stairway from the stairway’s narrow side. Applicable in winder, flared, curved and spiral stair types.

Wall Rail – a handrail affixed to the finished wall surface of a stairwell or hallway.

Wall Rail Brackets – bracketing, usually fabricated from metal, utilized to fasten wall mounted handrails to the finished wall’s surface. Wall rail brackets may be functional, ornamental, or both.

Wall Rail Fitting – an element which transitions wall rail sections either horizontally or in elevation.

Wedge – a tapered wooden element used to wedge a stairway’s treads and risers into the mortises of a box stringer.

Well Hole – see Stairwell.

Well Opening – see Stairwell.

Winder Stairway – a stairway whose primary or superior treads are of the winder type. A winder stairway may also include inline treads, which are subordinate to winder treads.

Winder Tread – a polygonal shaped tread. One or more winder treads are utilized to cause a stairway to turn off of a straight line from a few degrees to 180° or more.

Wood Plug – a circular wooden element utilized to refill a circular hole bored into a wooden component. The grain direction and attributes of a wood plug match those of the component receiving the plug.

Wreath – a term referencing any of the stairway’s or balustrade’s components that radius while ascending; e.g. a curved stairway is, in essence, a wreath.

Wreathed Drum – see Stairway Drum.

X-Taper Baluster – a baluster with a prominent descriptive element near its upper end, which requires consideration with respect to rake alignment.

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