The exponential growth of population, development of industry and technology, and the growth of civilization need more buildings especially in urban areas. Researches are focused with various alternatives to meet this need using limited or alternative resources or alternative technology. In this investigation, the new pattern of lightweight precast reinforced concrete floor panel referred as ‘C-channel’ has been studied. The lightweight concrete (LWC) and normal weight concrete (NWC) have been used. The Oil Palm Shell (OPS), the solid waste has been used as coarse aggregate in LWC. The ‘OPS concrete’ of G28 and ‘OPS hybrid concrete’ of G38 (known as LWC), and NWC of G30, G40, G50 and G60 are used. OPS hybrid concrete is made with 70% OPS and 30% granite by volume as coarse aggregate. The reinforced concrete panels of conventional full precast and semi-precast, and C-channels have been investigated. Three types of live loads such as 1.5kN/m2 for residential building, 2.0kN/m2 for hospital wards and 3.0kN/m2 for office and institute building are employed as per British Standard. The panels are designed based on loads of self-weight, partition wall, service and ceiling, screed and live load. The investigations have been focused on concrete usage, structural weight, and structural functions of both ultimate and service conditions. It has been observed that ‘C-channels’ are more economical and efficient in terms of saving in concrete, reduction in structural weight, higher load carrying capacity as compared with conventional full precast and semi-precast reinforced slab panels. The longer the span, the higher is the concrete saving as well as higher load capacity and also cost saving.