Purpose : Most buildings are hardly ever technically equipped to adapt to ever changing user demands. Adaptability of building components is known as an essential technical aid to facilitate flexible use. However, for designers and developers it is very difficult to foresee how design decisions related to flexible use effect the efficiency of the technical system, especially when adaptations have to be realized in the future. Due to the large number of variables and interrelations, a structured approach is indispensable to translate (future) user demands into technical solutions for flexible use. Therefore, the purpose of this paper is to present a novel method that can assist designers to systematically find suitable measures for flexible use. This method, named comparative selection method for adaptability measures (CSA method), is developed specifically to impartially select and compare adaptability measures. Design/methodology/approach : The CSA method is principally based on a performance approach, where technical solutions are compared and matched to performance requirements. To accomplish that, specific tools and theories were transferred from industrial product development. The CSA method displays the benefits of lifespan-oriented design, since a distinction is made between initial, once occurring effects and the effects that come with each expected adaptation. Findings : In contemporary building practice the initial phase is critical for decision making. By a number of case studies, the application of the CSA method reveals that tailor-made solutions with a high degree of adaptability are in fact the most efficient for the long term. Hereby the view is confirmed that a lifespan-oriented approach in design decisions is essential for a sustainable and future-proof building stock. Originality/value : The CSA method is a newly developed and unique support tool that assists in optimizing flexible building design through the search for best fit adaptability solutions.