The use of biomass in construction materials has emerged as a promising technique to enhance thermal insulation and mitigate carbon emissions, addressing crucial energy and ecological challenges. This paper introduces novel construction materials made from by-products of mint tea, one of MoroccoMorocco’s most abundant and culturally significant beverages. The thermophysical properties of the developed cement-based bio-composites integrating crushed spent tea and mint stems were determined using the hot-disk method. Experimental results indicate a 20% reduction in density and significant decreases in thermal conductivity and diffusivity, each exceeding 50%. These findings highlight the potential of these materials as lightweight insulators. ANSYS Fluent simulations demonstrate that our bio-composites clearly outperform traditional mortar in wall applications, suggesting a promising direction for future sustainable buildingBuilding practices.