• Developed by the Structural Technology Group at the Universitat Politèctica de Catalunya, the biological concrete cladding panel system comprises a waterproofing layer, structural layer, bioreceptive layer, and a reverse waterproofing layer that holds water for plants.

    Credit: Jameson Simpson

    Developed by the Structural Technology Group at the Universitat Politèctica de Catalunya, the biological concrete cladding panel system comprises a waterproofing layer, structural layer, bioreceptive layer, and a reverse waterproofing layer that holds water for plants.

First there were green roofs, then vertical gardens. Now there are microbial façades. Fungi and algae—once associated with decay and considered undesirable in architecture—have captured the attention of designers and researchers interested in the organisms’ latent aesthetic and practical potential.

The Structural Technology Group at the Universitat Politècnica de Catalunya (UPC) in Barcelona is developing a multilayered concrete cladding panel system designed to support the growth of mosses, fungi, and lichens. The biological concrete blends conventional Portland cement with the slightly acidic magnesium phosphate cement, which supports biological growth.

The façade system—the focus of UPC doctoral candidate Sandra Manso Blanco’s thesis—has four components: a waterproofing layer, a structural layer, a bioreceptive layer that promotes organism growth, and a reverse waterproofing layer that retains water for the plants. It promises several benefits, including carbon dioxide reduction, urban heat island effect mitigation, and applicability on existing structures. Perhaps its most compelling contribution is visual—a living patina that transforms every season.

Arup, Splitterwerk Architects, Colt International, and the Strategic Science Consult of Germany have collaborated on another microbial façade system. Housed within glass curtainwalls, the “bio-adaptive façade” uses living micro-algae to harvest solar power while providing shade. The envelope, which will be installed on the BIQ house project in Hamburg, Germany, for the International Building Exhibition (IBA) this spring, generates power in two ways: capturing solar thermal heat and generating biomass for harvest.

Moreover, the research team estimates that the amount of shading proffered will be directly proportional to solar access, since photosynthesis will drive the microbial growth within the liquid-infused glazing panels. “To use biochemical processes for adaptive shading is a really innovative and sustainable solution, so it is great to see it being tested in a real-life scenario,” says Jan Wurm, Arup’s Europe research leader.

Both the bio-adaptive façade and biological concrete take the pursuit of “green” to a new—and quite literal—level. However, using living microorganisms presents challenges. Will UPC’s lichen-covered concrete readily develop and retain an attractive appearance, or will it turn brown with the first heat wave? Will the BIQ house’s façade preserve its luminous chartreuse aura, or could a cold snap convert the algae-based fluid into a kind of dead pea soup?

Despite these unknowns, the effort to harness living matter as an integral part of building assemblies points to a future in which cladding embraces non-homogeneity, continual change, and life support—all radical, captivating approaches to envelope design.