The high volume of materials employed in conventional steel reinforced concrete floors results in significant resource consumption and corresponding CO2 emissions. Material-efficient load-bearing structures are increasingly gaining in importance against such a background. A new type of floor cross-section made of carbon concrete has been developed, In view of this, with an open web, optimised cross-section. It enables the concrete volume to be substantially reduced when compared to conventional steel reinforced concrete floors with a solid cross-section. The manufacturing approach developed, which involves thermoplastically shaped carbon-fibre reinforcement, is generally suitable for production in a precast facility. Experimental tests on full-scale test specimens demonstrate high load-bearing capacity and benign load-bearing behaviour under flexural stress, thereby confirming the system’s fundamental suitability for use as a floor structure. Furthermore, a reduction in material usage of up to 50% can be achieved whilst maintaining comparable load-bearing capability. A simplified carbon footprint (A1–A3) additionally highlights the system’s environmental potential compared to conventional semi-precast and in-situ concrete floors.