Chicago, Illinois / United States of America
The challenge consisted of connecting two floors within an opening surrounded by concrete beams. Due to the required turns and subsequent intermediate landings an orthogonal stair was not feasible. A helical staircase eliminates the need for these landings. By making the staircase the minimum width and radius it was able to fit within the tight confines of the structural opening, while maintaining code required headroom and hand clearances.
Two curved steel plates sandwich a corkscrew shaped low-iron glass railing with steel handrail. The connecting steel seat between the plates is recessed from the underside of the stringers to subtly expose the dual plate construction. Steel tread support grids are screwed into the stringers. Wood treads with a routed imprint of the supporting bar grid slip over the grid and are fastened with countersunk screws. A reveal between the treads and stringers allows movement of the wood and accentuates the supports below. The steel stringers were sandblasted prior to being electrostatically painted. The walnut treads provide a subtle transition between the walnut floors above and below.
Structural limitations resulted in a spare helical staircase, with distilled details, so that only the pure shape of the stair emerges.
Architect of RecordVinci | Hamp Architects, Inc.
General ContractorNorcon, Inc.
- Enspect, Inc.