Spiral stairs made of steel | Gustav Epple Bauunternehmung GmbH

2021, Stuttgart

With a conscious commitment to the Stuttgart location and a novelty in construction technology, Gustav Epple Bauunternehmung GmbH realized its new three-storey company headquarters with a monolithic exterior wall construction made of insulating concrete and thus completely dispensed with artificially produced insulating materials. Founded in 1909 in the Degerloch district as a small carpentry business, the general contractor is represented throughout Germany with several branches and sets high standards for sophisticated, creative and ecological construction with its "Anders.Bauen" philosophy. In keeping with the shape of the plot, the floor plan was designed as a slightly modified triangle. Inside the building, purist design with exposed concrete elements, wooden surfaces and a self-supporting spiral stairs made of steel dominate the approx. 4,300 square meters.

Sculptural dynamics

The working levels, created as an open-space concept, are arranged around the light-flooded atrium and are centrally connected by a spiral stairs made of steel. The steel staircase fascinates far beyond its function as a connecting element with its strong sculptural dynamics and corresponds to the open, clear architecture of the building. Rounded and designed to match the triangular ceiling openings, the steel spiral stairs are a striking eye-catcher for employees and visitors and, as a steel object, contrast with the interior design concept of exposed concrete and wood paneling.


Project details

  • self-supporting spiral stairs made of steel with parapet-high flat steel stringers on both sides as fall protection
  • 2 flights of stairs ground floor - 1st floor - 2nd floor; evenly rounded
  • diameter of inner/outer stringer approx. 2,320 mm / 5,320 mm
  • stringer height approx. 1,490 mm, stringer thickness approx. 15 - 25 mm
  • flight width approx. 1,500 mm
  • intermediate landing and stair head landing each analogous to the flight of the spiral stairs made of steel

  • sheet steel box-type treads, 6 mm, edged upwards on the front and back, cover plate welded in flush on the top, cavity insulation with mineral wool
  • stainless steel leading edge as edge protection, welded on top and flush with the decking edging
  • steel landings 1st/2nd floor similar to the tread construction, with additional cross ribs made of double girders, closed on the underside with cover plate -> box construction with smooth underside and different opening angles depending on the flight of stairs

  • flat steel construction on both sides of steel spiral stairs, welded horizontally on top and projecting inwards onto balustrade stringers, 50 x 10 mm
  • continuation on the landings of the steel spiral stairs
  • extension to the light cove with vertically welded flat steel, 40 x 10 mm
  • optical termination at the entrance and exit with vertical, rectangular hollow profile; also acts as a cable duct

  • CAD sketch and construction planning and extensive 3D detailed representations (axiometry) with freely selectable viewing angles for the steel staircase
  • calculation and preparation of the verifiable statics and a vibration analysis for the spiral stairs made of steel


a+r Architekten GmbH Stuttgart

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