Modern-day Alchemy
A RESEARCH TEAM AT THE UNIVERSITY OF MICHIGAN IS DEVELOPING A RECYCLED PLASTIC PANEL TO RIVAL NATURAL STONE AND REDUCE WASTE
Can recycled plastic convincingly mimic stone? Faculty at the Taubman College of Architecture and Urban Planning, University of Michigan, are fast at work turning post-consumer plastic into stone-like panels for applications such as facades, rainscreens and curtain walls. Thom Moran and Meredith Miller, professors and T+E+A+M co-founders, have collaborated with fabrication research specialist (and Taubman lecturer) Christopher Humphrey to develop Post Rock, a promising solution to help reduce the building sector’s carbon footprint.
Supported by a U.S. patent and an NSF grant, the team is advancing toward commercialization and plans to construct a two-storey mock-up in their fabrication lab in the near future, demonstrating how Post Rock can reshape sustainable construction practices.
Inspired by Rock
Post Rock initially drew its inspiration from plastiglomerate, a rock that naturally forms when ocean plastics meld with elements such as sand, seashells and wood. Post Rock’s thermoforming process involves heating moulds with controlled motion to blend the plastics in a way that mirrors geological processes. This results in a distinctive marbling reminiscent of sedimentary rock, in which one can “read” the rock’s formation from both natural and human-made inputs.
Waste Made Visible
Amid the ongoing climate crisis, it is increasingly crucial for designers and builders to select materials with an eye on their life cycle and potential for re-use. Post Rock combines various plastic types and sizes, creating a heterogeneous, chunky aesthetic. By showcasing plastic fragments, Post Rock encourages an awareness of the material life cycles at play, underscoring the idea that recycled plastics can match the aesthetic appeal of other cladding options with higher carbon emissions.
Mindful Reprocessing
Although recycled materials often reduce carbon footprints, reprocessing and transportation can counter these benefits. Post Rock proposes to minimize energy-intensive reprocessing by sourcing waste locally from automotive plants — plastic that is already Uv-stabilized, impact-tested and flame-resistant. Further, unlike rotomoulding, the robotically controlled method brings the source of heat close to the surface of the moulds rather than heating a large volume of space and placing a mould within it. The plastics used are infinitely recyclable, and a modular panel design allows for reinstallation on future buildings.
Tailored Stone
“Our process emulates the geological forces that create stone, but it also allows for the direct placement of materials into the mould by hand,” explains the research team. Manual composition, combined with the unpredictability of heat and movement, delivers panels that are custom but never identical. Architects and designers can selectively pick and place plastic aggregates into the panels to create custom colour combinations and surface graining, which collectively form a stone-look facade distinct from traditional cladding products.