Comparative Life Cycle Assessment of Two “Vegetarian Architecture” Pavilions

The goal to achieve carbon neutrality in the built environment by 2040 becomes more challenging every day. Moreover, the challenge goes beyond energy efficiency and embodied energy, and includes the quality of life of buildings’ occupants. Under this framework it becomes clear that a radical change is needed in the current construction practices. In this sense, ‘Vegetarian Architecture’ advocates a closer relationship with construction materials and an increased use of regionally produced and locally available materials and building techniques. The paper showcases two ‘Vegetarian Architecture’ pavilions built in Northern Italy: one with a load-bearing straw bale structure and the other with a light-earth infilled timber frame. We detail the local material selection and transportation processes, as well as provide bills of quantities. The comparative Life Cycle Assessment considers production, construction, and operation stages following EN15978, with Ecoinvent 3.8 database and OpenLCA software. IPCC2021 evaluates carbon footprint, and EN 16449 assesses stored biogenic CO2. The contribution analysis found that as material production approaches carbon zero, transportation becomes more important. However, due to the low carbon footprint of the two pavilions studied, transportation distances could be increased without a significant impact. Additionally, the use of fast-growing, locally sourced, bio-based materials like straw and reed allows the pavilions to store significant amounts of biogenic CO2, making them carbon negative. Vegetarian Architecture not only promotes alternative materials but also facilitates the development of local value chains and inter-sectoral synergies.