This chapter begins by considering how structure located on the perimeter of a building maximizes spatial planning freedom. In order to explore how structure contributes to and enhances building functionality, the chapter begins by reviewing two design strategies to achieve it - one based on identifying and applying 'critical functional dimensions', and a second more general architectural approach. The question of how to maximize functional flexibility was addressed with reference to the 'free plan'. The chapter illustrates the profound influence structure can have upon building function. By virtue of its permanence, structure both defines and limits the activities within a building. The degree of subtlety with which this is achieved depends upon the extent of the physical presence of structure in both plan and section. Whether it is maximizing functional flexibility or disrupting it, subdividing space or articulating function, structure must be thoroughly integrated with both the design concept and the functional requirements of the building.