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.


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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. 

  • 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

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.

Handrail construction for stringer stairs

The handrail supports of the stringer stairs consist of bent stainless steel round bars with a diameter of 6 mm. They are mounted on the inner balustrade stringer and the exterior handrail posts of the stringer stairs. These laser-cut handrail posts as well as the laser-cut filling brackets were welded on the outside of the stairs exterior stringers.

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.

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. 


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.

Architects: planquadrat