The precast industry offers slab panels of different geometries according to the field conditions. These slab panels are popular in temporary constructions and beneficial in sustainability but have some financial limitations and local constraints. For a long time, the construction industry has used the arch action method, which restricts the stresses to the compression zone in concrete members and develops the required load-carrying capacity. For the same motives, industrial buildings have preferred semi-circular precast roofs, but the morphology was not suitable. For the proposed slab in this research, firstly, the typical industrial precast slab panel was doubled in width to minimize the time and efforts required for its casting, curing, and placement. Secondly, that doubled-in-width slab was provided with the arch action to confine the stresses to compression and benefit from the section entirely. Lastly, the top of the slab was kept flat to take advantage of the roof space. All these changes aimed for structural stability, reduced material’s weight, improved load-carrying capacity, appropriate mobilization, and financial viability. A numerical approach and practical testing were adopted using the finite element modeling software, ABAQUS, to analyze load–deflection responses of both slabs through the concrete damage plasticity model. The proposed slab exhibited better performance as its capacity enhanced by about 1.5 times that of a typical slab. Although the volume of the material in the proposed slab increased slightly from 0.040 m3 to 0.045 m3, the reductions in joint filler materials, reinforcements, and efforts required for mixing and lifting machinery compensated for this increase significantly. Hence, the slab can be recommended for the industry to save the costs while taking heavier loads efficiently.