Our firm provided the structural design for a vertical mall expansion of 400,000 square feet for the Pacific View Ventura. A primary concern of the owner was to keep tenant interruption at a minimum, so we developed a phased construction schedule taking into account tenant lease expirations. The existing roof elevations made it possible for the new second floor to be built above the existing roof and thereby minimize tenant disruption. The foundation system (precast piles outside the existing structure and steel piles within tenant spaces) was built in vacated lease spaces. Columns, with a future splice below the existing roof elevation, were erected while the space was still unoccupied. At each grid we designed only one column within a tenant space, with the other main support column in the common mall area outside of the lease line.