Last edited 09 Jan 2018

Spiral stairs and helical stairs

Spiral and helical staircases can create a sense of light within properties, they can take up less space than traditional stairs, and can create a focal point to a design. They are often available as pre-fabricated kits.

Spiral staircase kits.jpg

Approved document K, Protection from falling, collision and impact, gives the following definitions.

  • A spiral stair is a stair in a helix around a central column.
  • A helical stair is a stair in a helix around a central void.

The approved document requires that spiral stairs and helical stairs are designed in accordance with BS 5395-2 Stairs, ladders and walkways. Code of practice for the design of helical and spiral stairs [1984 + AMD 6076, Corrigenda July 2008, C2, C3]. It gives recommendations for the design of internal and external helical and spiral stairs and gives guidance on the geometry of helical and spiral stairs, including:

Helical and spiral stairs involve the use of tapered treads. A tapered tread is a step in which the going (the depth from front to back of a tread, less any overlap with the next tread above) reduces from one side to the other. Approved document K requires that consecutive tapered treads, should use the same going. If a stair consists of straight and tapered treads, the going of the tapered treads should not be less than the going of the straight treads.

Measuring tapered treads.jpg

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