From a simple but elegant straight flight to beautiful hardwood spirals or the most complex sweeping helical design a new staircase will provide a stunning focal point to your home or workplace. But sometimes the terminology involved can be a little confusing, so here’s my step-by-step guide to your new staircase.
General: Staircase step: The staircase step is composed of the tread and riser.
Stair Tread: The tread is the part of the staircase that is stepped on. It is constructed to the same specifications (thickness) as any other flooring. The tread “depth” is measured from the outer edge of the step to the vertical “riser” between steps. The “width” is measured from one side to the other.
Stair Riser: The riser is the vertical portion between each tread on the stairs. This may be missing for an “open” stairs effect, subject to building regulations
Stair Nosing: An edge part of the tread that protrudes over the riser beneath. If it is present, this means that horizontally, the total “run” length of the stairs is not simply the sum of the tread lengths, the treads actually overlap each other slightly.
Starting step or Bullnose: Where stairs are open on one or both sides, the first step above the lower floor may be wider than the other steps and rounded. The balusters typically form a semicircle around the circumference of the rounded portion and the handrail has a horizontal spiral called a “volute” that supports the top of the balusters. Besides the cosmetic appeal, starting steps allow the balusters to form a wider, more stable base for the end of the handrail. Handrails that simply end at a post at the foot of the stairs can be less sturdy, even with a thick post. A double Bullnose can be used when both sides of the stairs are open.
Staircase Stringer or String: The structural member that supports the treads and risers. There are typically two stringers, one on either side of the stairs; though the treads may be supported many other ways. The stringers are sometimes notched so that the risers and treads fit into them. Stringers on open-sided stairs are often open themselves so that the treads are visible from the side. Such stringers are called “cut” stringers. Stringers on a closed side of the stairs are closed, with the support for the treads routed into the stringer.
Staircase Winders: Winders are steps that are narrower on one side than the other. They are used to change the direction of the stairs without landings. A series of winders form a circular or spiral stairway. When three steps are used to turn a 90 corner, the middle step is called a kite winder as a kite-shaped quadrilateral.
Stair Trim: Trim (e.g. quarter-round or baseboard trim) is normally applied where walls meet floors and often underneath treads to hide the reveal where the tread and riser meet. Shoe moulding may be used between where the lower floor and the first riser meet. Trimming a starting step is a special challenge as the last riser above the lower floor is rounded. Flexible, plastic trim is available for this purpose, however wooden mouldings are still used and are either cut from a single piece of rounded wood, or bent with laminations Scotia is concave moulding that is underneath the nosing between the riser and the tread above it.
Flight: A flight is an uninterrupted series of steps.
Floating stairs: A flight of stairs is said to be “floating” if there is nothing underneath. The risers are typically missing as well to emphasize the open effect. There may be only one stringer or the stringers otherwise minimized. Where building codes allow, there may not even be handrails.
Staircase Landing or Platform: A landing is the area of a floor near the top or bottom step of a stair. An intermediate landing is a small platform built as part of the stair between main floor levels and is typically used to allow stairs to change directions, or to allow the user a rest. As intermediate landings consume floor space they can be expensive to build. However, changing the direction of the stairs allows stairs to fit where they would not otherwise, or provides privacy to the upper level as visitors downstairs cannot simply look up the stairs to the upper level.
Stair Runner: Carpeting that runs down the middle of the stairs. Runners may be directly stapled or nailed to the stairs, or may be secured by specialized bar that holds the carpet in place where the tread meets the riser.
Spandrel: If there is not another flight of stairs immediately underneath, the triangular space underneath the stairs is called a “spandrel”. It is frequently used as a closet. Staircase: This term is often reserved for the stairs themselves: the steps, railings and landings; though often it is used interchangeably with “stairs” and “stairway”.
Stairway: This term is often reserved for the entire stairwell and staircase in combination; though often it is used interchangeably with “stairs” and “staircase”.
Spiral stairs: Spiral stairs wind around a central pole. Spiral stairs typically have a handrail on the outer side only, and on the inner side just the central pole. A squared spiral stair assumes a square stairwell and expands the steps and railing to a square, resulting in unequal steps (larger where they extend into a corner of the square). A pure spiral staircase assumes a circular stairwell and the steps and handrail are equal and positioned screw-symmetrically. A tight spiral stairs with a central pole is very space efficient in the use of floor area. The term “spiral” is used incorrectly for a staircase from a mathematical viewpoint, as a mathematical spiral lies in a single plane and moves towards or away from a central point. A spiral staircase by the mathematical definition therefore would be of little use as it would afford no change in elevation. The correct mathematical term for motion where the locus remains at a fixed distance from a fixed line whilst moving in a circular motion about it is “helix”. The presence or otherwise of a central pole does not affect the terminology applied to the design of the structure. Spiral stairs in medieval times were generally made of stone and typically wound in a clockwise direction (from the ascendor’s point of view), in order to place at a disadvantage attacking swordsmen who were most often right-handed). This asymmetry forces the right-handed swordsman to engage the central pike and degrade his mobility compared with the defender who is facing down the stairs.
Helical Staircases: Helical staircases or circular stairs do not have a central pole and there is a handrail on both sides. Helical staircases have the advantage of a more uniform tread width when compared to spiral staircases. Helical staircases may also be built around an elliptical or oval platform. A double helix is possible, with two independent helical stairs in the same vertical space, allowing one person to ascend and another to descend, without ever meeting if they choose different helixes. Fire escapes, though built with landings and straight runs of stairs, are often functionally double helixes, with two separate stairs inter twinned and occupying the same floor space. This is often in support of legal requirements to have two separate fire escapes. Both spiral stairs and helical stairs can be characterized by the number of turns that are made. A “quarter-turn” stair deposits the person facing 90 degrees from the starting orientation. Likewise there are half-turn, three-quarters-turn and full-turn stairs. A continuous spiral may make many turns depending on the height. Very tall multi turn spiral staircases are usually found in old stone towers within fortifications, churches and in lighthouses.
Bespoke staircases: staircases are available in various kit and “off the shelf” formats. However, these types of ready made staircases never fit as well as a true bespoke staircase which has been professionally designed and manufactured by craftsmen to fit into a specific location. In order to make a bespoke staircase it is essential to first carry out a full on site survey. Boss stairs will visit the site with a professional surveyor and a staircase designer to take accurate measurements and give advice on the various design options available. These options would include; the plan or layout, the materials to be used in the construction of the staircase and also the type and style of railing system. First we would determine the layout and plan which in many cases is dictated by the space available. Then decide what type of timber to be used for the flight itself. For a hardwood flight we recommend Oak stairs, Walnut stairs, Ash stairs, Sapele stairs or Mahogany stairs. Contrasting timbers can be used to give a contemporary design, for instance Walnut treads with Oak or even painted risers look very effective. There is also the choice of a straight or cut string as well as the type and style of railing system to use, be that traditional wooden spindles and newel posts or perhaps a glass balustrade or even wrought iron can be used to make a very attractive feature. There are many designs of wooden spindles and an infinite number of patterns of wrought ironwork. Finally, we would determine the use of any additional details such as special starting steps or volutes. Back at the office the designer will draw up a CAD plan and provide a detailed estimate of the costs involved. These costs will include for manufacture and supply plus any installation and/or finishing, if required.
The Staircase Railing System: The balustrade is the system of railings and balusters that prevents people from falling over the edge.
Banister, Railing or Handrail: The angled member for hand holding, as distinguished from the vertical balusters which hold it up for stairs that are open on one side; there is often a railing on both sides, sometimes only on one side or not at all, on wide staircases there is sometimes also one in the middle, or even more. The term “banister” is sometimes used to mean just the handrail, or sometimes the handrail and the balusters or sometimes just the balusters.
Volute: A handrail end element for the Bullnose step that curves inward like a spiral. A volute is said to be right or left-handed depending on which side of the stairs the handrail is as one faces up the stairs.
Turnout: Instead of a complete spiral volute, a turnout is a quarter-turn rounded end to the handrail.
Gooseneck: The vertical handrail that joins a sloped handrail to a higher handrail on the balcony or landing is a gooseneck.
Rosette: Where the handrail ends in the wall and a half-newel is not used, it may be trimmed by a rosette.
Easings: Wall handrails are mounted directly onto the wall with wall brackets. At the bottom of the stairs such railings flare to a horizontal railing and this horizontal portion is called a “starting easing”. At the top of the stairs, the horizontal portion of the railing is called a “over easing”.
Core rail: Wood handrails often have a metal core to provide extra strength and stiffness, especially when the rail has to curve against the grain of the wood. The archaic term for the metal core is “core rail”.
Baluster or Spindle: A term for the vertical posts that hold up the handrail. Sometimes simply called guards or spindles. Treads often require two balusters. The second baluster is closer to the riser and is taller than the first. The extra height in the second baluster is typically in the middle between decorative elements on the baluster. That way the bottom decorative elements are aligned with the tread and the top elements are aligned with the railing angle.
Newel: A large baluster or post used to anchor the handrail. Since it is a structural element, it extends below the floor and sub floor to the bottom of the floor joists and is bolted right to the floor joist. A half-newel may be used where a railing ends in the wall. Visually, it looks like half the newel is embedded in the wall. For open landings, a newel may extend below the landing for a decorative newel drop.
Baserail or Shoerail: For systems where the baluster does not start at the treads, they go to a base rail. This allows for identical balusters, avoiding the second baluster problem.
Fillet: A decorative filler piece on the floor between balusters on a balcony railing.
Handrails: Handrails may be continuous (sometimes called over-the-post) or post-to-post (or more accurately “newel-to-newel”). For continuous handrails on long balconies, there may be multiple newels and tandem caps to cover the newels. At corners, there are quarter-turn caps. For post-to-post systems, the newels project above the handrails. Another, more classical, form of hand railing which is still in use is the tangent method. A variant of the Cylindrical method of layout, it allows for continuous climbing and twisting rails and easings. It was defined from principles set down by architect Peter Nicholson in the 18th century.
Rise: The rise height or rise of each step is measured from the top of one tread to the next. It is not the physical height of the riser; the latter excludes the thickness of the tread. A person using the stairs would move this distance vertically for each step they take.
Tread Depth: The tread depth is measured from the edge of the nosing to the vertical riser.
Going: The going is measured from the edge of the nosing to the edge of nosing in plan view. A person using the stairs would move this distance forward with each step they take.
Total Run or Total Going: The total run or total going of the stairs is the horizontal distance from the first riser to the last riser. It is often not simply the sum of the individual tread lengths due to the nosing overlapping between treads.
Total Rise: The total rise of the stairs is the height between floors (or landings) that the flight of stairs is spanning.
Slope or Pitch: The slope or pitch of the stairs is the total rise divided by the total run (not the individual riser and treads due to the nosing). It is sometimes called the rake of the stairs. The pitch line is the imaginary line along the tip of the nosing of the treads. In the UK, stair pitch is measured in degrees from the horizontal.
Headroom: Headroom is the height above the nosing of a tread to the ceiling above it.
Walk line: For curved stairs, the inner radius of the curve may result in very narrow treads. The “walk line” is the imaginary line some distance away from the inner edge on which people are expected to walk. Building code will specify the distance. Building codes will then specify the minimum tread size at the walk line. To avoid confusion, the number of steps in a set of stairs is always the number of risers, not the number of treads.
For information on glass staircases click here.