Siedle is a German firm specializing in doorbell systems, access control, and intercoms. It’s one of those companies you may not have heard of, but if you live in Europe, you’ve likely come across their intercoms in apartment buildings and offices. This family-owned business, in operation since 1750, still manufactures all its products in Germany and is highly vertically integrated. The company has always been located in Furtwangen in the picturesque Black Forest. So when Siedle CEO Gabriele Siedle wanted to establish a cultural center, the Siedle Haus, the location was set in stone.
¨Our long-held wish, our idea, is to create a place in Furtwangen that brings people together, inspires them and excites them,” Siedle said.
The center will house the Siedle family’s art collection and continue the work of the Horst and Gabriele Siedle Art Foundation. To emphasize its role as a community gathering space and highlight the family’s deep local roots, the building’s facade is designed for maximum impact. The entire interior facade is composed of 1,067 formwork elements, based on a 3D scan of a historic family building. This formwork effectively serves as a cast of the original house where the family began their business. In that house, they once cast clocks—a traditional industry in Furtwangen. Now, their art museum features a wall that replicates their former home.
A nice touch by Brandlhuber+Hotz+Architekten, the facade serves as the centerpiece of the Siedle Haus. It is part of a 25-meter-high wooden structure, encased by a 13-meter glass facade.
“To achieve such a detailed cast of the former residence, we developed a unique process that had never been done at this scale before…The method was an enormous challenge, but in this way we succeeded in realising the design concept without any changes,” said Michael Eichmann, lead architect of hotz+architekten.
They reveal that the large-format formwork matrices showcase intricate details, like the wooden shingles and imperfections of the original building. The complete print covers 720 square meters and used 150,000 liters of black quartz sand at a layer height of 0.3 mm. Printed over ten months by Voxeljet, the 3D scanning was conducted by JBKS, while Sandhelden post-processed the pieces by sealing the surface with epoxy resin and infiltration for added durability. The pieces were then covered in PU foam and cast in concrete to create the final structure. 3D-printed formwork saves time and money, and in this case, capturing high-fidelity details, such as wood grain, contributed to creating an authentic cast of their original house.

SANDHELDEN and Voxeljet showcase their technology brilliantly in this project. The facade will become even more striking with Picasso’s artwork displayed on and around it. While 3D-printed formwork doesn’t receive as much attention as direct 3D printing, it can be an invaluable tool for construction companies, offering significant time savings. In some cases, formwork can even be reused for projects like tunnel construction, adding further cost benefits. This project also highlights the level of detail and high throughput that binder jet technology can achieve. Though binder jetting is sometimes overhyped, I believe that exploring novel materials for unique construction challenges may reveal applications where this technology truly shines.