Spiral Stair — Layout variation
Category: Layout variation
Spirally curved staircase with a central load-bearing spindle.
The spiral stair is a spirally curved staircase with a central, solid core – the spindle – in which the winder treads are radially anchored. The spindle carries all loads; on the outside, the stair is bounded by balusters or an outer stringer. The plan is typically round, although spiral stairs in square stairwells also exist. Unlike a helical stair with a stairwell opening, the spiral stair has no free inner space. For residential buildings with up to two apartments, DIN 18065 permits a usable width of 80 cm between spindle and handrail if the spiral stair is the sole access to a living space. Spiral stairs are strongly design-driven: freestanding in the room they appear most powerful, while leaned against a wall they read more subtly. They are particularly suited to galleries, secondary stairs and rooms with very limited floor space.
Related terms
Related terms: Helical Stair, Harp Stair, Curved Stair, Walking Line, Winder Tread, Newel Pipe.