First there were green roofs, then vertical gardens. Now, there are green walls. The Structural Technology Group at the Universitat Politèctica de Catalunya (UPC) in Barcelona is developing a multilayered concrete panel system designed to support the growth of mosses, fungi, and lichens. The so-called biological concrete is based on the use of two types of cement: conventional Portland cement and magnesium phosphate cement (MPC)—which has a slight acidity and supports biological growth.
In the system, which is the focus of the PhD thesis of Sandra Manso, materials are combined to form four layers: a waterproofing layer, a structural layer, a bioreceptive layer that aids the growth of organisms, and a reverse waterproofing layer that retains water for the plants. Although not yet commercially available, the innovative product promises several benefits, including CO2 reduction via the use of organisms, reduction of urban-heat-island effect, and applicability for existing structures.
In addition—and perhaps its most compelling contribution—the product could exhibit a beautiful, living patina that transforms throughout the seasons. Although achieving and maintaining this attractive patina are perhaps the least certain aspects of Manso's research thus far, the effort suggests that future building cladding might embrace non-homogeneity and continual change in addition to life-support—all radical, yet captivating approaches to envelope design.
Blaine Brownell is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.