Concrete use in buildings significantly contributes to global CO2 emissions. Floor systems constitute a major portion of the concrete in building structures, making them a prime target for material reduction. Conventional design methods to calculate strength and deflection of concrete slabs often avoid complex calculations and save time, but they can be overly conservative and lead to inefficient use of materials. This research aims to leverage modern design techniques, specifically Grasshopper, to reduce CO2 emissions and resource use in concrete slab design. As an early step into this direction, three methods are presented and demonstrated: (i) determines the span length at an arbitrary point on the floor, (ii) computes the reinforcement field based on Finite Element Analysis (FEA) results, and (iii) updates element stiffness based on their internal forces obtained from FEA to approximate moment redistribution. It is concluded that the presented methods are feasible and they can be developed further into a holistic design workflow that can support architects and engineers in saving material and reducing emissions.