One of the major challenges of a building expansion is the juncture between new and existing structural systems. Structural design entails knowledge of earlier systems—whether reaching back a hundred years or ten—as well as a thorough knowledge of available materials and their applications. In some cases, the expansion joins several older buildings at different locations or levels. Most often, the existing building must continue to function while the expansion is constructed, necessitating structural modifications or temporary structures. Our sixty years of experience helps us understand the challenges of expansion projects and provide appropriate structural solutions.