A recycled plastic panel designed by T+E+A+M in Detroit, Post Rock transforms waste into sustainable building materials. Developed by University of Michigan professors Meredith Miller and Thom Moran with Christopher Humphrey, it mimics geological processes to create customizable, stone-like panels with marbled aesthetics. Using UV-stabilized automotive plastic waste from Detroit, the material reduces emissions and meets fire safety standards. Its modular, energy-efficient design advances sustainability while showcasing recycled materials’ architectural potential. Displayed at the Craft Contemporary Museum, Post Rock moves toward commercialization, redefining waste management and sustainable construction practices.
Post Rock, a groundbreaking building material developed at the University of Michigan, transforms waste plastic into stone-like panels for architectural applications. Created by professors Meredith Miller and Thom Moran, co-founders of the architectural practice T+E+A+M, in collaboration with fabrication research specialist Christopher Humphrey, Post Rock is poised to reduce the construction industry’s carbon footprint while showcasing the aesthetic potential of recycled materials. With a U.S. patent and support from a National Science Foundation grant, the project has moved from research to near-commercial viability, with plans to construct a two-story mock-up to demonstrate its practical applications.
Aesthetic and Environmental Inspiration
Post Rock draws its inspiration from plastiglomerates, naturally occurring rocks formed in oceans where plastics fuse with materials like sand and shells. The thermoforming process developed by the team mirrors geological processes, using heat and controlled motion to blend various plastics into panels with distinctive marbled patterns. This approach produces unique visual effects reminiscent of sedimentary rock while highlighting the origins of the recycled material.
“Our process emulates the geological forces that create stone, but it also allows for the direct placement of materials into the mold by hand,” the team explains. By enabling designers to place and arrange plastic fragments, the method allows for customizable panels with tailored color combinations and surface graining.
A New Use for Waste Plastic
Post Rock’s material sourcing is highly localized, focusing on automotive plastic waste from Detroit’s thriving car industry. This choice not only reduces transportation emissions but also takes advantage of materials that are already UV-stabilized, impact-tested, and flame-resistant. Plastics like polyamides, often used in car dashboards and electrical components, meet the fire safety standards required for building exteriors while delivering a robust and versatile base for the panels.
The automotive industry in Detroit generates more than 300,000 tons of plastic waste annually, providing a rich source of materials for Post Rock. This regional connection gives the panels a distinct aesthetic, with bright orange veining reflective of their origins. “This is a version of Post Rock that is very much regionally sourced through the automotive industry. And hopefully, you can see that,” says Miller.
Advancing Sustainable Building Practices
Amid the ongoing climate crisis, Post Rock addresses the need for materials that are both sustainable and visually compelling. By combining plastics of different types and sizes, the panels create a heterogeneous, chunky aesthetic that makes the material lifecycle visible. This transparency encourages a dialogue about sustainability while challenging the perception that recycled materials cannot match the aesthetic appeal of traditional cladding options like stone or concrete.
Unlike conventional manufacturing methods, Post Rock’s fabrication process minimizes energy-intensive steps. Instead of heating large volumes of material in rotomolding, the team’s robotic system applies heat directly to the surface of the molds, reducing energy use. Moreover, the plastics used in Post Rock are infinitely recyclable, and the modular design of the panels allows for easy reinstallation in future buildings.
From Lab to Market
Though initially conceived as an academic experiment, Post Rock is evolving into a scalable product. “We really started the project as architects, as designers. But I think we’ve had to learn how to be researchers and entrepreneurs,” says Miller. With continued testing and refinement, the team is working to ensure Post Rock complies with fire safety regulations governed by the National Fire Protection Association.
Currently on display at the Craft Contemporary Museum in Los Angeles, Post Rock exemplifies the potential of design to elevate waste materials. Its creators are committed to balancing functionality and aesthetics, ensuring the panels not only perform well but also redefine what buildings can look like. “There’s recycled content products that are used for insulation or subflooring, and I’m glad those exist. But as architects, we’re ultimately thinking about how this will impact what buildings look like,” Miller concludes.
Toward a Circular Future
By harnessing waste plastic and transforming it into durable, visually striking building materials, Post Rock demonstrates how innovation and design can drive sustainable practices in the construction industry. As it nears commercialization, this material promises to reshape architectural possibilities while addressing the global challenge of waste management.
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