Stabilizer and plasticizer systems were studied for a PVC waterproofing sheet formulation to be processed by calendering. Combinations of stabilizer-lubricant systems that contained (Ba, Cd, Zn), dibasic lead phosphite, epoxidized soybean oil, barium stearate, calcium stearate, and stearic acid were evaluated. Oven aging tests showed that the system that contained 2 phr (Ba, Cd, Zn) stabilizer, 0.5 phr barium stearate, 5 phr epoxidized soybean oil, and 0.25 phr stearic acid was satisfactory. Combinations of diisodecylphthalate (DIIP), tricresyl phosphate (TCP), polybutylene adipate (PBA), and NBR were evaluated as the plasticizer system. Tensile properties in the machine and the transverse directions, cold flex temperature, loss of volatile matter content, and aging properties were studied as functions of the DIIP and PBA contents. A plasticizer system of 35 phr DIIP and 18 phr PBA was found to be satisfactory. The final formulation was processed at industrial scale and the product was characterized for its tensile properties, cold flex temperature, tear resistance, weldability, permeability to water, shrinkage, and its resistance to heat, light, acid, and water.