A spiral staircase is a round stair system in which the individual steps connect to a center column, hence forming a complete circle. The diameter of the circle creates the diameter of the staircase.
This article explains the general features of the spiral staircase and its varieties.
Features of Spiral Staircase
The threads or steps of a spiral staircase rotate about a central point as we move up the stair or down the stair, hence making a spiral design.
Note: The spiral stair is not a helical stair. A helical stair also called a curved staircase, does not have a central column.
The depth of each step of a spiral stair remains uniform and equal. The handrails move around the perimeter of the spiral curve formed, thus making the stair more iconic.
Design Factors of Spiral Staircase
The six essential factors considered in the design of the spiral staircase are:
- Height of the staircase
- Diameter of Staircase
- Location of the staircase
- Style of Threads, handrails and the balusters
Spiral stairs can be customized based on the design, budget, and the safety concerns of the client.
Among the factors mentioned, the first three are considered primary requirements to commence the design.
The determination of the height of the spiral staircase is the most crucial measurement in the design. It is the measurement on which the safety concerns of the spiral staircase lie.
First, ensure that the top platform stays with the landing platform and determine the height according to that. Once the height is defined,
The number of steps = Total Height of the stair/ Riser Height or Space between each step
The angle of rotation of each step is the angle at which each step rotates about the central column. It is 30 degrees for most of the spiral staircase.
Stair’s Full Rotation = Number of Steps x Rotation Angle
A staircase of 12 steps has a rotation angle of 12 x 30 = 360 degrees; 9 stepped stair has 9 x 30 = 270 degree rotation.
The width of the stair forms the diameter of the spiral staircase. The diameter of the stairs decides whether it fits to the space provided. Always design the spiral staircase based on the respective building codes of the area that takes into consideration the functionality, loads, and traffic coming on it.
Classification of Spiral Staircase
The spiral staircase can be of different types based on the material used for their construction:
Spiral Concrete Stairs
Spiral concrete gives an ultra-modern look to the space. It can be constructed with or without a central column. It employs a special formwork arrangement which requires skilled labor and expertise.
Spiral Glass Stairs
Spiral glass stair provides a classic style to the space. Spiral glass stair, mostly constructed with a central steel column, has glass threads connected throughout its height. The treads can be either round or angular or adjusted according to the wall shape.
Spiral Wood Stairs
Wooden spiral stair provides a natural and traditional look to the interior space. Used for both residential and commercial areas. Wooden spiral stairs are now coming in installation kits according to the space provided by the client. It consists of ready-to-install elements.
Spiral Steel Stairs
Spiral steel stair is the top demanded stair option. It is designed to fit into any space. It consists of a central column to support the threads. It is used for interior as well as outdoor space. Outdoor steel spiral stairs are galvanized and treated to face the environmental conditions.
Also Read: Design Requirement of Staircase
Also Read: Components of Staircase