A renovation and addition bring an historic church complex into the 21st century.The Diocese of Toronto approached architectsAlliance (aA) about renovating the St. James Cathedral Centre with two objectives in mind. On a practical level, they wanted more space for the cathedral’s outreach program and the Diocesan archives, as well as quarters for the Dean of the Cathedral and visitors. At the same time, the Anglican leadership wanted to make a statement about the Church’s relevance to contemporary Canadian society. “The idea of the addition was to convey an image of the Church itself as a kind of more open institution, much more transparent and contemporary,” said aA’s Rob Cadeau. “[It was] really driven by the dean, who wanted to refresh the image of the Church.”The architects designed the addition to the Parish Hall as a glass cube. “There’s a lot of use of glass, both as a contemporary material, but also to convey that idea of transparency, for the symbolism of the project,” said Cadeau. At the same time, the see-through extension “defers to the old building. It doesn’t take away from the presence of the old building as opposed to solid masonry construction.” The upper stories of the stick system curtain wall are wrapped in a floating sunscreen comprising repeating bands of laminated glass. “It was very important to the church that there be a sort of green aspect to the design in the way it’s conceived and constructed,” said Cadeau. “So the sunscreen was designed as a passive means of providing shading.” To maximize shading during the summer and solar gain during the winter, aA ran the sunscreen design through shadow analysis testing in ArchiCAD. They worked with Stouffville Glass to engineer both the sunscreen and the curtain wall. The sunscreen hangs on a vertical system of stainless steel brackets anchored to the HSS beams surrounding the slab edge of the second and third floors. The glass panels’ interlayer is printed with a linear pattern recalling the original building’s narrow button bars. “The idea of the lines within the sunscreen was to create a finer grain of detail on the glass,” explained Cadeau. The curtain wall itself is built of Solarban 60 glass. “It still provides the U value we wanted, but we didn’t want too much reflectivity because it’s a fairly small building,” said Cadeau. The firm also improved the thermal performance of the original Parish Hall building, which opened in 1910. With help from a building envelope consultant, they ran a thermal analysis of the structure to determine how much spray foam insulation to insert between the masonry wall and a new stud wall. The goal was to boost insulation while allowing some heat transfer. “That’s very important in heritage upgrades,” said Cadeau. “[T]he mistake you can make is over-insulating. Masonry walls rely in some sense of heat loss so that the water [trapped inside] never freezes. If the water absorbed in the brick freezes it will start to crack the brick.” The new St. James Cathedral Centre unites a previously disconnected cluster of buildings across an enclosed courtyard. In that way, aA suggests, the glass addition functions as a contemporary cloister. “In a larger, urban planning sense [the objective] was to complete the ensemble of buildings, create more of a connection between the buildings as a whole,” said Cadeau.