PARTISANS is leading the adaptive reuse of the historic Canadian Pacific Building at 69 Yonge Street—reinvigorating the landmark heritage office building with 127 new residential units. Constructed in 1913 to serve as the corporate headquarters for the Canadian Pacific Railway, the Canadian Pacific Building was renowned for its architectural expression, as well as for its title as the tallest building in British Empire at the time of its completion. To transform this storied landmark from office to residential use, PARTISANS designed a sensitive new addition on the south-east corner that enlarges the floor plate of the existing building and adds five stories above the existing roof—all of which are designed to be invisible from existing viewplanes on the street below to preserve views of the distinctive heritage roofline which is defined by three monumental copper-clad cupolas. The addition features white precast cladding and curtain wall glazing designed as a contemporary reinterpretation of the existing structure’s proportions and rhythms, arched forms, limestone cladding, and verticality, while maintaining the legibility of its classical composition of plinth, shaft and crown.