Wangentreppe bei Heraeus

Stringer stairs and all-glass railing

Fascinating interplay of shapes

On its premises in Hanau the global technology group Heraeus constructed an innovation centre that is characterized by its visionary and sustainable design.


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Project description

Curved sculptural stairs at Heraeus

On its premises in Hanau the global technology group Heraeus constructed an innovation centre that is characterized by its visionary and sustainable design. Beside the office facilities the new building accomodates furthermore technology and laboratory sectors for reserarch and development. Spacious galleries and coffee areas offer sufficient space for communication and exchange. The filigree stringer stairs in the representative foyer captivate with their fascinating interplay of shapes. The stairs in helical design extend accross three floors and are perfectly complemented by the all-glass railings at the galleries.

Handrail construction for stringer stairs

For the double-sided wooden handrails, which were realised on-site, MetallArt installed a sophisticated substructure made of steel. It consists of bent stainless steel supports with a diameter of 6mm. They were screwed on the inner balustrade stringer of the staircase. On the outer side of the exterior steel stringer there are laser-cut profile posts, arranged in regular spacing of approx. 1000 mm, which were completed by bent round bars made of stainless steel serving as handrail support. The filling supports were manufactured by laser cut, too, and welded to the outside of the stringer stairs in regular spacing of approx. 125 mm.

Treppe des Jahres Heraeus
Project details

All-glass railing with steel frame

To complete the stringer stairs in the foyer MetallArt created curved and straight all-glass railings for the galleries on each floor. Their transparent appearance visually emphasises the filigree steel design of the stringer stairs and rounds out the convincing architectural layout.

The laminated glass panes, showing a thickness of 20 mm and a length of 2,000 mm were cast in the glass pocket free of constraint forces and sealed by means of a verifiable casting resin technology. The top cover of the frame was equipped with an EPDM rubber profile.

To provide for the substructure for the on-site installation of the wooden handrails, U-sections made of steel were attached on top of the glass panes of the railings.

Sculptural stringer stairs with steel soffit lining

The sculptural stringer stairs featuring a smooth underside steel cladding impress with an especially light and flowing appearance. The consistent helix angle of the stairs stringers is the decisive aspect for the homogenous design in which the geometric changes within the half and stair head landing do not not appear. The stringer stairs are designed with raised stringers showing variying spaces of their upper and lower edges towards the run of the tread steps.

In addition to the delivery and assembly of the stringer stairs MetallArt prepared the CAD construction planning in 3D design as well as the verifiable structural analysis and the vibration resistance calculation.

Stringer stairs featuring structural supporting underside soffit

An indispensible element of this stringer stairs construction is the smooth underside cladding made of 4-6 mm thick steel sheet. This component, providing for structural support, is flush-welded between the stringers and of corresponding shape regarding the stair stringers.

Further information

  • Ground plan stringer stairs: six-flight stairs, evenly rounded with 2 flights each
  • Exterior stringer: flat steel concealing the treads, up to approx. 1,150 mm vertical height of the stringers
  • Inner stringer: flat steel balustrade, up to approx. 1,900 mm vertical height of the stringers
  • Tread step construction: folded steel treads welded between the stringers
  • Staircase landings for stringer stairs: 1 intermediate landing and 1 stair head landing per floor, circular design with additional stiffening profiles according to structural requirements

Award for staircase of the year

The German specialist portal honoured the remarkable stringer stairs as staircase of the year 2019 in the category “sculpture”. With its convincing stair design MetallArt won this important price, awarded by the renowned German specialist portal, already during the last years in different categories.


planquadrat, Darmstadt