1. What are the key parts of a staircase?
The humble staircase can open up a wealth of terminology that can cause confusion. The diagram below helps to demystify some of these terms:
Strings: A span of timber to which treads and risers are attached to support a flight or run of stairs
Tread: The horizontal part of the stair that is stepped on.
Risers: The vertical part of the stair (where no risers are present this would be referred to as “open risers”). The number of steps in a staircase is counted by the number of risers, not the number of treads
Balustrade: A row of balusters (spindles) topped by a handrail serving as a safety guarding and along the edge of a staircase
Handrail: Following the staircase to support and guide during ascending or descending a staircase and an element to grasp in case of a fall
Newel: A large baluster or post acting as a structural element to anchor the balustrade to the floor or stair.
Spandrel: The triangular space underneath a staircase (when there is not another flight underneath)
Winder: A stair that is narrower on one side to enable a turn in the staircase. 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
Apron: A facia covering the ends of rough strings, carriage pieces, and the joists of landings.
Other key terms
Flight: An uninterrupted series of steps.
Rise: The height of an individual step (i.e. this differes from the hight of a riser as it refers to the height that must be stepped)
Going: The depth of an individual step
Pitch: The slope of the staircase measured as the ratio between the rise and going
Walkline: The path that an individual would follow up or down a staircase
2. Is it possible to have two steps in a winder flight?
The problem with a two step winder is that the walk-line going can often exceed the limits set by the building regulations. Winders should have a rise that is the same as the other flights forming the staircase and a going that is not less than the going of the other flights.
The going of the winder should also fall within the limits set, for example, by table 1 of Approved Document K. Where the going of a private stair should be between 220mm and 300mm. To stop the going from becoming too long , causing the user to have an uncomfortable stride pattern, the control formula of twice the rise plus the going (2R + G) being between 550 mm and 750 mm should also be applied. If the stair is narrow then the walk line going may not exceed these limits and the stair would comply with the building regulations. However, wider stairs would cause the walk-line going to become too much making the stair non-compliant.
There are two standards which each provide a method to determine the walk-line going;
BS 585-1: 1989, Wood stairs — Part 1: Specification for stairs with closed risers for domestic use, including straight and winder flights and quarter or half landings and
BS 5395-1: 2010, Stairs – Part 1: Code of practice for the design of stairs with straight flights and winders.
3. What is the difference between a split newel and a two part newel?
A split Newel refers to a Newel Post that has been split in length and can form the end of a balustrade when it finishes against a wall. A two-part Newel is formed by a newel base which is often joined to the string and an upper part that is fixed into the newel base (care should be taken when using newels of this type to ensure that they can support sufficient load).
For a full list of standards and regulations for staircases download a copy of the BWF Stair Design Guide
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