Recycling of waste materials reinforces the effort of promoting a sustainable environment and ecological management. In parallel, growing technologies unfold their wings to develop new materials from waste materials. The present study advocates the meticulous usage of crumb rubber (CR) a by-product of waste tyres to transform a lightweight -high-strength structural member. The usual open moulding technique was followed to fabricate a polymer composite sandwich wherein cover sheets were prepared by the resin-impregnated- Kevlar mat sheets and the core was fabricated by CR-reinforced epoxy. Four different variants of CR inclusion were followed (0, 5, 10 and 15 wt%) to cast a core. The structural integrity was evaluated using three-point flexural testing. The flexural testing results declare a 50% enhancement in both flexural strength and flexural modulus for the highercontent CR-reinforced core. The analytical evaluation of flexural stiffness, transverse rigidity and core shear modulus acknowledges the improved interfacial shear strength to combat the delamination. A stringent postfracture study explores the nature of strengthening mechanisms and endorses core strengthening. The finite element-based numerical validation of experimental results substantiates the good agreement between the experiment results at the expense of approximately 10% accuracy.