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Last edited 17 Jan 2018
Types of stairs
Stairs are used to create a pedestrian route between different vertical levels by dividing the height between the levels into manageable steps. Very generally, the word 'stairs' refers to a staircase, whereas the word 'step' refers to the steps that make up the staircase.
The type of stairs suitable for different situations will depend on:
- The supporting structure.
- The amount and type of usage it is likely to receive.
- The space available and its geometry.
- The difference in height between the top and bottom.
- Materials selection
Stairs may be:
- Open tread or closed tread.
- Provided with handrails on one or both sides, or in the middle on wide stairs.
- Enclosed by walls or open on one or both side.
- Different widths and lengths and may have a range of step dimensions.
- Different geometries.
Some of the most common types of stair geometry include:
Where there are more than 36 risers in consecutive flights of stairs, Approved Document K requires that there is at least one change of direction, with a landing that has a minimum length equal to the width of the stairs.
Quarter-turn, or L-shaped, stairs comprise a straight flight of stairs that makes a 90-degree turn after a landing. This type can be considered safer than a straight staircase since the landing reduces the number of treads in one flight and provides a place to rest.
This type of stairs is similar to a quarter-turn staircase, but consists of winders which are wedge-shaped treads, wider on one side than the other. Winders allow a turn by 90-degrees (single winder) or 180-degrees (double winder).
This type of stair is a compact design with flights resembling a circle (or part of a circle), and centred around a single vertical column. Similar to winder stairs, the treads are wedge-shaped but differ in that they are all uniformly sized (except the final one).
Although spiral stairs are often considered to be aesthetically pleasing and effective in terms of space, they may not be the most convenient in terms of frequent use as the treads can often be less easy or safe to traverse than other types of stairs.
A helical stair similar to a spiral stair, but the helix wraps around a central void rather than a column.
Also known as arched stairs, this type of stair comprises a continuous flight that is shaped like an arch, with no landings. The treads are wedge-shaped similar to winder stairs. Although achieving an elegant aesthetic, curved stairs are difficult to construct since all basic details, banisters, and so on, need to be curved.
 Alternating tread
A stair with paddle-shaped treads where the wide portion is on alternate sides on consecutive treads.
Different types of stair use include:
Approved document B defines a ‘protected stair’ as ‘…a stair discharging through a final exit to a place of safety (including any exit passageway between the foot of the stair and the final exit) that is adequately enclosed with fire resisting construction’.
See: Protected stairway for more information.
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