Their goal was to establish a space “that brings people together, inspires, and excites.” This heartfelt vision of entrepreneur Gabriele Siedle and her late husband Horst has come to life with the Siedle Haus. Starting at the end of 2024, this cultural center will showcase the impressive art collection of the Siedles, making it accessible to the public in Furtwangen (Germany). A unique feature of the center is its interior, which includes a life-sized concrete cast of a residential building belonging to the Siedle family.

SANDHELDEN´s client voxeljet utilized large-format 3D printers to create 1,067 facade formwork elements for this distinctive structure. The project engaged numerous architectural firms, planners, and craftsmen. The ambitious design was executed by Brandlhuber+Hotz+Architekten, a collaborative firm formed by Arno Brandlhuber b+ from Berlin and hotz+architekten from Freiburg, led by Michael Eichmann.

The roots of the Siedle Haus trace back to the history of the Siedle company. Furtwangen, home to 9,000 residents, is nestled in the heart of Germany's Black Forest. The family-owned Siedle company has been manufacturing in this area since 1750, which has a rich legacy in clockmaking and precision manufacturing. What began in a Black Forest house with components for clocks evolved into a manufacturing company with a new facility in 1870. Today, Siedle is recognized globally for its building communication technology, including door and home intercom systems.

In the 1980s, current managing director Gabriele Siedle and her husband Horst began collecting art, amassing a large collection of classical modernism, featuring works by artists like Pablo Picasso and Ernst Ludwig Kirchner, now housed in the charitable Horst and Gabriele Siedle Art Foundation. These artworks, along with a variety of educational programs, will be showcased at Siedle Haus in the future.

The Siedle Haus features a concrete cast of the original building at its core, realized in intricate detail through 3D-printed matrices. Using advanced additive manufacturing and post-processing techniques, voxeljet and SANDHELDEN transformed the previously dilapidated structure into a lasting form. The facade created from concrete now serves as the interior facade of the new exhibition space, which holds the art collection, encased in a striking wooden structure that spans up to 25 meters, reminiscent of a classic Black Forest home. A glass facade reaching 13 meters high surrounds the building, enhancing its openness and accessibility.

Digitally revitalizing the old Black Forest house, a scanning process was implemented, merging laser measurement with photogrammetry, to capture the 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,” explains Michael Eichmann, lead architect of hotz+architekten. This digital 3D facade image was crucial for the production of large-format formwork matrices, showcasing the intricate details like wooden shingles and imperfections of the original building.

Voxeljet's 3D printing technology brought this vision to life, creating the Siedle Haus layer by layer from CAD data. The total printed surface area of 720 square meters was derived from approximately 425 gigabytes of CAD information. From September 2021, voxeljet manufactured the high-precision data using the 3D sand printing process, producing 1,067 formwork matrices the size of Euro pallets over a ten-month period. During this time SANDHELDEN directly post-processes these formwork matrices by applying their infiltration process to gain a sealed and resistant surface.

The binder jetting technology played a pivotal role in this project. With a build area of 4x2x1 meters, the printer was able to generate around 150,000 liters of detailed printed sand, demonstrating its efficiency and precision for large-scale endeavors like the Siedle Haus.

Utilizing a 300-micrometer layer of silica sand, the binder jetting process applies a binder selectively to bond the sand, creating intricate parts layer by layer. This method stands out in facade construction, making projects like the Siedle Haus cost-effective and precise.

Voxeljet’s technology enabled the creation of detail and complexity that traditional manufacturing methods could not achieve. The annual rings of the wooden beams are distinguishable, and practical features such as recesses for lights and cameras were integrated into the printed matrices. After this, all 1,067 matrices were treated with epoxy resin by SANDHELDEN to enhance stability, followed by shaping with PU foam and casting in concrete to create a refined representation of the original house.

Additive manufacturing has been making strides in architecture for some time. Instead of directly printing concrete, SANDHELDEN is able to combine 3D printing with concrete casting through printed formwork. Over the years, they've advanced this approach with partners like voxeljet from initial tests to real construction applications.

The opening of the art and culture center is planned for the end of 2024. With the concrete casting as its architectural core, the Siedle Haus now makes an impressive reference to the region and the origins of the company.