Non-standard stairs have an important role in architecture, but their complex details pose significant fabrication challenges. One of the preferred materials for custom stairs is steel, which can be shaped in different ways, but with high costs and a lot of components. 3D printing can unlock an entirely new vocabulary of shapes, previously unavailable with traditional systems, and materials like steel, wood, and concrete. Only a minimal amount of 3D-printed plastic is required to deliver a very thin, stable shell. Complex topologies can be achieved with less effort, such elements can optimize the structural performance or improve functional aspects, as well as introduce a radically different aesthetic.
The market of interior non-standard staircases, leaving aside the in-situ concrete stairs, goes in two main directions. On the one hand, there is the umbrella of bespoke-made products, on the other hand, there is the family of industrial in-kit products. The first case is generally defined by a specific design that is adapted to the context in every single component, this is also one of the main factors that raise the prices of these products. The overall result is usually intended to be organic, coherent as a whole.
The in-kit products are instead meant to be mass-manufactured, to reduce the design and manufacturing costs. In this staircase typology, the adaptability is shifted from the design phase to the assembly. The interaction between the standardized components is designed to guarantee a range of configurations. This advantage has a side effect from the aesthetical perspective: it is difficult here to achieve an aesthetical result that seems designed for the specific case, usually, these products are manifesting this adaptation, with discontinuities.
AM could bridge the two typologies with an affordable on-demand customized fabrication, creating staircases that can adapt to a specific context without losing the overall aesthetic quality.
As indicated in the CSC Leading Edge Forum (2012), the advantages of using 3D printing for such a product for interiors and medium-scale architecture components can be listed as follows: affordable customization; allows the manufacture of more efficient designs; lighter, stronger, less assembly required; one machine, unlimited product lines; efficient use of raw materials (less waste); pay by weight; complexity is free; batches of one, created on demand; print at point of assembly/consumption; new supply chain and retail opportunities. In the same report, there are highlights that, there are still some areas in need of further development. In particular, the possibility of printing large volumes economically, expanding the range of printable materials, using multiple materials in the same printer, to improve durability and quality as a final result. All these benefits make it worth exploring AM technologies for real applications. Architects are offered the chance to reinvent architectural components and the ecology of materials of the built environment by exploring forms and processes deemed impractical or inconceivable before.
With innovative construction materials/methods and better decision-making systems, not only projects are getting smarter but also it is an opportunity to build our environment more sustainable (Beyhan 2018).