- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 11 Feb 2019
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.
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:
- Alternative materials, components and methods of design and construction.
- Fire protection and means of escape.
- Load tests.
- Design geometry.
- Typical layouts for stairs.
- Relationship between rise and going.
- Measurement of clear width and goings.
- Maximum gap between column and tread.
- Calculation of going.
- Calculation of clear headroom.
- Structural materials.
- Sizes of stairs.
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.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
Guidance for local authorities and consultancies setting planning conditions.
A real deal – at last?
How does anastylosis help in the reconstructing of ancient monuments?
More than just aesthetic and historic values and meanings.
An exciting and novel collaboration between the RIBA and the SPAB.
Republic of Ireland updates to planning and development.
The different types of pile foundation.
Achieving a net-zero carbon UK by 2050.
Responding to an invitation to tender.
Statutory instruments laid in Parliament to amend the Climate Change Act.
How will we pay for infrastructure post-Brexit after EIB has gone?