Reduction of steel sheet thickness as a means of reducing vehicle weight may necessitate some method of enhancing flexural stiffness. Three basic types of sheet stiffening methods have been investigated: integrally formed rib stiffeners, foam-backed sheets and embossed material. Means of calculating the stiffness obtained by each method is presented. The stiffness of integrally formed rib-stiffened sheets depends on the size and spacing of the ribs. The increase in stiffness of foam-backed sheets depends on the thickness and density of the rigid plastic foam. Embossed patterns increase sheet stiffness provided the embossing is relatively deep compared to sheet thickness.