Wax based Structural Stiffening Foam is traditionally applied in an interior cavity of the vehicle for structural reinforcement. The Structural Stiffening Foam is epoxy-based reactive foam which is used to reinforce frame rails, body cavities or body panels. The Structural Stiffening Foam provides unrivalled and enhanced durability, strength and stiffness for vehicles. The Wax based Structural Stiffening Foam adds structural integrity without adding weight to the chassis and thus making for better mileage and helping improve crash safety by absorbing impact energy.