A new class of sustainable building composite materials is developed, made out of recycled fibers waste, of sand from crushing inert waste and of lime. The fibers come from abundant and available bio-based or mineral fibers such as cellulose, glass wool, or rock wool. The crushing sand comes from inert building waste and is used instead of river sand which is a resource under shortage. Lime is, like the other two constituents, available locally. The targeted performance is minimizing the environmental footprint compared to the current building materials available on the market in terms of CO2 emissions and grey energy consumption over the entire life cycle. Additional specific objectives are a lifetime up to 60 years, the incorporation of at least 75% recycled or end-of-cycle materials and a high potential of further reuse or recycling. These performances must be optimized under all the structural, thermal and durability constraints of specific building applications. A test campaign has proved the energy-efficient nature of the processing and excellent potential in terms of insulation, fire resistance and mechanical strength, for materials containing a rate of paper fibers larger than 50%.