A lack of appropriate guidelines for the design and assessment hampers the development of multifunctional flood defenses like parking garages in quays and houses in dikes. The aim of the present paper, therefore, is to gain insight in the structural performance of multifunctional flood defenses and to provide a tool to evaluate design alternatives. For this purpose we have developed a generic method to determine the function of structural elements regarding flood protection. A study of diverse multifunctional flood defenses showed that the derived structural element types are indeed generic. We then applied the method to a real case, which showed that it factually provides more clarity and insight in the advantages and disadvantages of adding functions to flood defenses. This method will therefore advance the design and application of multifunctional flood defenses. @en