Stairs | Stairways

Stairs, stairways, staircases, or stairwells, are building components that provide users with a means of vertical movement with the distribution of separate and individual vertical steps. In a building setting, a flight of stairs refers to a complete series of steps that connects between two distinct floors. Either as conscious design decisions or as reactions to existing spatial conditions, stairs can take on a variety of organizational types from straight runs to spiral, L-shaped, U-shaped, or circular forms. Each stair step is typically comprised of a horizontal tread and a vertical riser.

Stairs are designed to establish a route or bridge between vertical levels by dividing the distance or height into steps feasible for occupants to travel. Stairs refers to a stairway, staircase, or stairwell while steps refers to the individual vertical distances that make up the stairs. There are many various types of stairs that can be straight, curved, or a set of straight pieces connected at a turn or landing. There are general requirements for a stair’s minimum and maximum tread depth and riser, with a tread being the component of the stair that the occupant steps on and a riser being the vertical component between each tread. 

Stairs Guides
Browse through our curated Stairs Guides for additional categorizations, tips, details, variations, styles, and histories of Stairs. Guides provide additional insights into the unique properties and shared relationships between elements.
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90° Winding Stairs
Elevation illustration of a woman ascending a set of 90° winding stairs

A 90° Winding Staircase makes a 90° turn up towards the next level. The staircase allows the user to turn a corner and change their direction. The primary benefit of a 90° Winding Staircase over a flat landing straight staircase is that the 90° Winding Staircase saves much more space. The winders are the steps that are narrower on one side than the other, and when three steps are used to turn the 90° corner, the middle step is called the kite winder, as it looks like a kite-shaped quadrilateral. 

Set of dimensioned drawings of 90° Winding Stairs with measurements for height and width
A 90° Winding Staircase makes a 90° turn up towards the next level. The staircase allows the user to turn a corner and change their direction. The primary benefit of a 90° Winding Staircase over a flat landing straight staircase is that the 90° Winding Staircase saves much more space.

Set of dimensioned drawings of 90° Winding Stairs with measurements for height and width
90° Winding Stairs
Height:
Width:
Length:
Depth:
Weight:
Area:

Winding Steps:
Narrow End (Min.): 6” | 15 cm
Tread Run (Min.): Must meet required tread dimensions 12” | 30.5 cm inward from narrow end

Width (Min.): 36” | 91.4 cm
Rise (Max.): 7” | 18 cm
Run (Min.): 11” | 28 cm
Landing (Min.): 36” | 91.4 cm
Handrail Height: 34”-38” | 86.5-96.5 cm

Drawings include:
90° Winding Stairs side elevation, side (person), front, plan

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Three-Quarter-Turn Stairs
Side elevation illustration of a woman climbing a set of Three-Quarter-Turn Stairs

Three-Quarter Turn Stairs change their directions through 270° by the time the stair reaches the next floor. The direction is changed three times through three right angles, with the upper flight crossing the bottom one. In this type of construction, an open well is formed. This type of stair is normally used when a space has a greater vertical distance but a limited length. Some flights have very few risers, and the landings can provide a place to stop and rest during ascension.

Dimensioned plan and elevation drawings of Three-Quarter-Turn Stairs measuring height and width
Three-Quarter Turn Stairs change their directions through 270° by the time the stair reaches the next floor. The direction is changed three times through three right angles, with the upper flight crossing the bottom one. In this type of construction, an open well is formed.

Dimensioned plan and elevation drawings of Three-Quarter-Turn Stairs measuring height and width
Three-Quarter-Turn Stairs
Height:
Width:
Length:
Depth:
Weight:
Area:

Width (Min.): 36” | 91.4 cm
Rise (Max.): 7” | 18 cm
Run (Min.): 11” | 28 cm
Landing (Min.): 36” | 91.4 cm
Handrail Height: 34”-38” | 86.5-96.5 cm

Drawings include:
Three-Quarter-Turn Stairs side elevation, side (person), front, plan

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Z-Shaped Stairs
Illustration of a woman climbing a flight of Z-Shaped Stairs in elevation

A Z-Shaped Staircase is a specialized staircase that is occasionally needed to fit around awkward architecture. It uses two parallel 90° turns that create a shape similar to that of the letter “Z” if seen from above. The stairs follow a zig-zag line with the tread and the rise continuous from start to exit. It is also referred to as a Double L Stair, as it is very similar to the L Stair but with two intermediate landings, one near the top and one near the bottom with a 90° change of direction at each landing.

Collection of plan and elevation drawings of Z-Shaped Stairs with dimensions
A Z-Shaped Staircase is a specialized staircase that is occasionally needed to fit around awkward architecture. It uses two parallel 90° turns that create a shape similar to that of the letter “Z” if seen from above. The stairs follow a zig-zag line with the treads and rise.

Collection of plan and elevation drawings of Z-Shaped Stairs with dimensions
Z-Shaped Stairs
Height:
Width:
Length:
Depth:
Weight:
Area:

Winding Steps:
Narrow End (Min.): 6” | 15 cm
Tread Run (Min.): Must meet required tread dimensions 12” | 30.5 cm inward from narrow end

Width (Min.): 36” | 91.4 cm
Rise (Max.): 7” | 18 cm
Run (Min.): 11” | 28 cm
Landing (Min.): 36” | 91.4 cm
Handrail Height: 34”-38” | 86.5-96.5 cm

Drawings include:
Z-Shaped Stairs side elevation, side (person), front, plan

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Curved Stairs | Arched Stairs
Elevation illustration of a man climbing a flight of Curved or arched stairs

Curved Stairs, also referred to as Arched Stairs, use a wider radius than a Spiral Staircase to wind upwards to a second floor or landing. They can be varied in materials from wood to glass and wrought iron to add a traditional or modern feel. And they are great for commercial properties like retail stores, showrooms, and other public spaces, but they also add a glamorous effect in an office or residential location. It is often used as a focal point in the center of an interior space, as it draws in visitors to explore the next level.

Set of plan and elevation drawings of Curved | Arched stairs with dimensions
Curved Stairs, also referred to as Arched Stairs, use a wider radius than a Spiral Staircase to wind upwards to a second floor or landing. They can be varied in materials from wood to glass and wrought iron to add a traditional or modern feel. And they are great for commercial properties.

Set of plan and elevation drawings of Curved | Arched stairs with dimensions
Curved Stairs | Arched Stairs
Height:
Width:
Length:
Depth:
Weight:
Area:

Inner Radius: At least 2x the width of the stair
Narrow End (Min.): 10” | 25.5 cm

Width (Min.): 36” | 91.4 cm
Rise (Max.): 7” | 18 cm
Run (Min.): 11” | 28 cm
Landing (Min.): 36” | 91.4 cm
Handrail Height: 34”-38” | 86.5-96.5 cm

Drawings include:
Curved (Arched) Stairs side elevation, side (person), front, plan

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Spiral Staircase (Residential)
Dimensioned drawing of Spiral Staircase with measurements for width, height, and stair risers

Spiral Stairs follow a helical arc, and the treads radiate around a central pole. They are often found in industrial contexts, and the reduced tread width allows for a very compact design. However, this can be a disadvantage as it can be very steep. A Spiral Staircase typically has a handrail on only the outer side; the inner side just has the central pole. As the central pole provides the structural support for the stairs, it does not need many additional support structures, which makes installation easier than other types of stairs.

Spiral Stairs follow a helical arc, and the treads radiate around a central pole. They are often found in industrial contexts, and the reduced tread width allows for a very compact design. However, this can be a disadvantage as it can be very steep. A Spiral Staircase typically has a handrail.

Spiral Staircase (Residential)
Height:
Width:
Length:
Depth:
Weight:
Area:

Drawings include:
Spiral Stair elevation (person)

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