Expanded polystyrene (EPS) was discovered in 1839 in Berlin and became a widely used material in airplanes manufactured for World War II due to its extremely low density. It is this characteristic that makes it a suitable material for thermal and acoustic insulation, often specified in buildings, but also widely used in packaging. A rigid cellular plastic, it is the result of polymerizing styrene in water, whose end product are expandable beads that have a diameter of up to 3 millimeters. Unfortunately though, this material takes more than 500 years to decompose and, in the process, leaches harmful chemicals into the environment. Recycling is possible, but it is complex and costly. This means that most of the Styrofoam produced to date still remains on the planet, taking up valuable space in landfills, or worse, broken into tiny pieces and interfering with ocean life. "Decomposition Farm: Stairway" is a temporary installation that offers a possible solution to the environmental issues related to construction waste in the architectural field.
Even though Styrofoam is a huge environmental problem and mankind is highly dependent on it, there seems to be a light at the end of the tunnel. Researchers have discovered that Tenebrio molitor, a species of darkling beetle, is able to metabolize expanded EPS, a durable single-use plastic, when in its larval stage. The material is broken down through its stomach enzyme and the insects excrete it as a substance safe enough to grow plants.
This pavilion in South Korea, developed by Yong Ju Lee Architecture, consists of a spiral structure with a metal core that is filled with EPS, molded using a 6-axis industrial robot (IRB-4600 by ABB). A 1.5 meter wide hot wire cutter attached to the end of the robotic arm was implemented, which can carve out pieces of the foam. To develop the volume of the project, all shapes are made using ruled surfaces (which are obtained by joining straight lines).
According to the architects, “In geometry, a surface S is ruled if through every point of S there is a straight line that lies on the surface. Without any modeling software in the late 1800s, Antoni Gaudí applied the forms of ruled surface to simplify the modeling in that they are constructed from straight lines. Now, thousands of computer-generated surfaces are boolean-ed out elaborately from the volumetric mass through the exquisite robot control.”
A huge number of holes are carved in the polystyrene to provide habitats for the larvae. After the digestion process, the excretion produced nourishes the moss, which is also attached to the foam, eventually creating a new ecosystem within the artificial environment. In other words, it becomes a man-made structure that is completely melted by nature. “Linear-patterned elements are aggregated into a large spiral staircase, that involves human into this systematic cycle. This radical experiment can suggest a new sustainable approach in architectural field, more than carbon-zero construction – carbon-negative building life cycle.”
