Hybrid Envelopes

”Yes, questions … Morphology, Longevity, Incept dates … If only you could have seen what I've seen, with YOUR EYES.”                                        Roy Batty in the “Eye Manufacturer” scene, Blade Runner, 1982, Dir. Ridley Scott

The envelope of the Zollverein School of Management and Design strikes us as a fascinating and technologically advanced project. It features one single skin that effectively addresses all the challenges typically associated with an envelope, creating a truly inspiring vision. While it appears to be made from a single material, it is actually the result of the hybridization of two elements: concrete and water.

Twenty years later, we still focus on envelopes made primarily from natural materials, aiming for a decarbonized solution that minimizes complexity and elaboration. This approach emphasizes minimal handling of the original materials to enhance their potential for reuse and recycling. We envision a reimagined Zollverein, where concrete is substituted with lighter, more ecologically sustainable materials, while incorporating manual system operations. Conversely, we are also developing technological envelopes designed to generate energy, featuring photovoltaic glass surfaces that seamlessly blend in terms of color, appearance, and shape with the overall design. These envelopes include automated detection and control systems that enhance building comfort through natural ventilation and solar protection.

Between these two typologies, we explore hybrid approaches in our projects and research, focusing on both materiality and construction techniques. We can leverage advanced technology for complex manufacturing and installation processes while embracing a form of material primitivism driven by concerns over climate change and the desire to reduce the embedded energy in construction.

In this context, we emphasize projects that predominantly use traditional materials like earth and wood, which are technologically or morphologically manipulated to create contemporary envelope solutions.

The prefabricated earth walls developed by Martin Rauch at Lehm Ton Erde exemplify the technical refinement of ancient processes, such as rammed earth construction. Their ongoing innovations demonstrate how these seemingly outdated methods can be revitalized and made relevant in today’s context.

Additional techniques complement this expertise, such as the construction of walls using unstabilized extruded clay elements. These elements are positioned and compressed by a robot, as seen in the recording studio at Clay Rotunda in Bern, designed by Gramazio Kohler + Lehmag AG. This process creates a self-supporting wall through geometric design, crafted from compressed raw earth. This approach exemplifies the fusion of traditional materials with modern technology in their execution and manufacturing.

Hybridization can also involve combining low carbon footprint materials to create complex and, most importantly, durable structures, paired with technological envelopes that are more carbon-intensive but long-lasting. These envelopes protect elements that would typically have a higher ecological impact (such as the structure), ensuring the overall longevity of the project.

Our recent experience allows us to illustrate both concepts of hybridization—the symbiosis of materials and the integration of different techniques.

The Solar Greenhouse, built by the students and team of the Master in Advanced Ecological Buildings and Biocities (MAEBB) of the Institute for Advanced Architecture of Catalonia (IAAC), features a wooden structure made on-site using trees selected from the same park where the Fab Lab is located. There, the wood is sawn, dried, and processed into laminated structures and CLT panels.

The envelope, composed of medium-scale glass panels, is designed with low-iron glass to ensure maximum transparency and treated with a surface coating that minimizes reflectivity. This allows for optimal solar radiation collection in the Greenhouse’s south and west orientations. The components supporting the glass panels are produced in the Fab Lab using CNC technology and 3D printing. For the roof, certain glass panels are converted into photovoltaic glass to generate the energy required to operate the greenhouse and seedbed.

Similarly, the construction of the Impluvium Redux (Rice University), led by Juan José Castellón, (xmade), and completed in Barcelona last summer, provided an opportunity to explore the hybridization of craftsmanship and technology. The Cumella family's in-depth knowledge of stoneware as a material (60% clay + 40% recycled fired ceramics) is combined with processes carried out by a collaborative robot (cobot). This fusion of techniques is employed to produce the ceramic pieces for the Impluvium.

At the same time, the design concept is driven by the idea of creating a prototype made possible through a network of small, high-value, high-tech companies that manufacture their components within a limited geographical area.

A hybrid materiality is also proposed, with the option to pre-stress the ceramic elements, optimizing the structural sections and allowing the Impluvium to be dismantled and reassembled indefinitely. The elements are modular, enabling quick, dry assembly without waste generation, as the material removed by the cobot through subtraction techniques is recycled back into the extrusion process.

The roof of the Impluvium is a technologically sophisticated deployable element, featuring a textile sheet folded in origami and supported by a metallic substructure. This design is engineered to manage water within the building—collecting, storing, and regenerating it—and can also be disassembled for relocation or repurposing.

This prototype exemplifies one of the most fruitful approaches we have identified: the combination of technological strategies with a profound understanding of the materials used.

Main image: Impluvium Redux, Barcelona, 2024, Juan José Castellón, Rice University/xmade. Photo © Frau Recerques Visuals

Impluvium Redux, Barcelona, 2024, Juan José Castellón, Rice University/xmade. Video © Frau Recerques Visuals