A low density fabric substrate for a medical bandaging product. The substrate has a plurality of longitudinally-extending voids formed in the fabric for permitting water penetration through the fabric thickness from one of the major faces to the other major faces. A reactive system is impregnated into or coated onto the substrate and remains stable when maintained in substantially moisture-free conditions and hardens upon exposure to sufficient moisture to form a rigid, self supporting structure. A soft, flexible protective material covers at least one of the major faces of the substrate along its length to provide a cushioning barrier between the substrate and the skin of a patient when the material is in use.