Increasing awareness of the high-embodied energy of many building materials is motivating designers and manufacturers to explore the inclusion of low-carbon, bio-based ingredients in new products. Pervasive, energy-intensive materials like concrete, steel, and aluminum make up a significant proportion of buildings. Together, these three materials alone comprise nearly a quarter of all global carbon emissions, and they are used primarily within the built environment. These materials also occupy a significant part of our annual planetary resource budget—a concept employed by the international nonprofit Global Footprint Network to measure the quantity of resources humanity can sustainably process (manufacture, use, and discard) each year. Designers are therefore experimenting with the utilization of less-intensive organic feedstocks in both mineral- and bio-based building products.
An example is the use of microbes to “grow” masonry. The Durham, N.C.–based Biomason recently teamed up with Amsterdam-based StoneCycling to create BioBasedTiles. An industry leader in the manufacture of structural cement made from microorganisms, Biomason sought to partner with StoneCycling due to its expertise in construction waste mitigation. BioBasedTiles consist of 15% biocement, a binder that produces a material made by bacteria and sand resembling coral, and StoneCycling’s recaptured mineral waste, such as granite dust. The result is a tile with a near-zero carbon footprint (biocement has only 5% of the emissions of conventional cement) that also reduces the volume of construction and demolition waste. In addition, the product boasts improved quality and fabrication: according to StoneCycling, BioBasedTiles are three times stronger and 20% lighter than typical concrete masonry units. The precast modules also cure in 72 hours—compared with 28 days for conventional cement.
Prometheus Materials is also taking a bio-based approach to improving the environmental performance of cement. The Longmont, Colo.–based company produces an organic biocomposite using a method developed at the University of Colorado Boulder. In this case, the active agent is microalgae, which the firm adds to a sand mixture that it pours into concrete masonry unit-shaped molds. Like biocement, the algae binds together the loose material, converting it into a durable substance resembling coral. The company claims that its current concrete blocks emit 90%t less CO2 in their manufacture than traditional CMUs and that improvements in production efficiency and aggregate sourcing will lower the impact even further. “We'll be at zero-net carbon soon, and then we have a clear path to get to carbon negative,” said Loren Burnett, the CEO of Prometheus Materials’, in a CPR News interview.
For Studio Lionne van Deursen, the biological agent of choice is bacterial cellulose . Also called microbial cellulose, BC is a dense mesh-like substance grown by bacteria. The material is hydrophilic, meaning it naturally retains a high quantity of water, and exhibits a crystalline structure with high mechanical strength. Most commonly recognized in the making of kombucha tea, in which a fermented brew of bacteria and yeast forms a cellulosic mass on the liquid’s surface, bacterial cellulose offers promising properties for various uses, including biomedical, packaging, and decorative object applications. Studio Lionne van Deursen’s Unfold explores the capacity of bacterial cellulose to function as an expandable, profiled sheet material. The Netherlands-based removes the water from BC biofilm and adds various origami-like folds, demonstrating the strength and flexibility of this low-carbon, bio-based material.
For the founders of London-based Blast Studio, design opportunities abound in fungi. The firm constructs self-supporting structures of mycelium, the hyphae or root system from which mushrooms grow. To fabricate its Tree Column, Blast Studio 3D-printed a biocomposite feedstock composed of mycelium and wastepaper coffee cups in successive layers. The shape of the column, loosely derived from the undulating cross section of trees, is intended to create self-shading, moisture-holding ridges conducive to growing fungi. Notably, a freshly printed column is alive: the paper is a feedstock for the growing mycelium, which eventually consumes it entirely. The resulting root structure is then an ideal growing medium for different species of mushrooms, which can be selected for mechanical as well as nutritional properties. Like the other novel bio-based design pursuits mentioned above, the Tree Column represents a design future that is not only kinder to the Earth but also intriguingly transdisciplinary—blurring architecture with fields like agriculture, marine biology, and gastronomy. One can therefore imagine expanding the discipline to address health, safety, and welfare as not only human concerns but also planetary ones.
