Geo- and bio-based materials as circular solutions towards a regenerative built environment

Abstract

Global environmental awareness pushes the building sector to achieve carbon neutrality and find low embodied impact solutions. The European Union has set a 2050 goal and is regulating the whole carbon life cycle (embodied and operational) as part of the Energy Performance of Buildings Directive (EPBD). In this scope, low-tech geo-bio-based materials can have an important role in reducing the embodied environmental impacts and carbon in buildings. Due to their low processing production, these materials fit in a circular approach since they can be easily recycled or returned to the natural environment at a minimal environmental cost. However, the lack of quantitative data on the life cycle environmental performance of some non-conventional techniques can hinder their use since professionals cannot compare the benefits of such versus conventional practice and comply with future EPBD requirements. This paper aims to contribute to the topic by presenting results on the life cycle environmental performance of earthen materials and bio-based insulation products versus conventional solutions based on data from Environmental Product Declarations or studies following the EN15804 standard. The results show that earthen materials can reduce the potential environmental impacts by about 50% versus conventional mansory walls. At the same time, bio-based insulation solutions offer the advantage of lowering operational carbon emissions and stocking carbon (e.g. straw has a Global Warming Potential performance about three times better than Expanded Polystyrene). The benefits of using earthen and bio-based materials are also discussed for the different building life-cycle stages, focusing on the possibility of reusing/recycling these materials in a closed-loop approach.