Bioregional Mineralisation with Agricultural Resources for Construction (BIOARC) explores how agricultural residues and regional microbial resources can be combined to create low-impact construction materials rooted in local ecological contexts. Working across four European bioregions, the project investigates wheat in Poland, sunflower in France, hops in Germany and rice in Italy as feedstocks for the development of construction boards, insulation materials, acoustic panels and partition wall systems. The project combines agricultural by-products with biomineralisation processes, in which microorganisms induce the formation of calcium carbonate minerals that act as natural binders within plant-based composites. Alongside biomass resources, BIOARC has isolated mineralising bacterial strains from limestone-rich and calcium-rich environments within each participating region, establishing a bioregional approach in which both material feedstocks and microbial agents originate from the same local context. The demonstration presents a biomineralised construction prototypes alongside the agricultural residues, bacterial cultures and microscopy imagery that underpin its development. Together, these artefacts communicate the transformation from regional agricultural by-products and environmental microbial communities into construction-oriented materials. By linking agriculture, biotechnology and construction, BIOARC demonstrates how place-based material systems can support circular value chains, reduce reliance on conventional mineral-intensive products and contribute to more resilient and regenerative approaches to the built environment.