Environmental performance of a cork-based modular living wall from a life-cycle perspective

Abstract

In a previous work, the authors of this paper proposed a new modular living wall made with expanded cork agglomerate, fully describing the designing process and discussing the overall mechanical performance. It was then shown that several key environmental and functional requirements were met by favouring the use of insulation cork board (ICB), a thermal insulation material with low environmental impact and good water retention.In this paper, the authors have extended the characterization of that living wall system to assess its performance under real conditions, with different plant species, geographical orientations and seasons. For this purpose, a prototype was built with four façades, facing north, south, east, and west. The area of façade covered by vegetation and the carbon sequestration provided by two different plant species were then monitored for over a year. Annual values of carbon uptake, experimentally determined, were further used to update an environmental life cycle model of the system.The results suggest that this modular living wall performs well in terms of plant development and carbon sequestration, with Festuca glauca showing a higher cumulative carbon uptake and a higher percentage of façade coverage than Thymus pulegioides, regardless of the geographical orientation and season. This essentially results from the greater amount of biomass produced by Festuca glauca and its hanging behaviour. It was also concluded that this new modular living wall is an eco-friendly choice, when assessed from a life cycle perspective, since it has a negative carbon balance over its life cycle (22.7 kg CO2eq per square meter).