Retrofitting a City School approaches the restoration of the 100-year-old Our Lady of Perpetual Help Catholic Elementary School as an example for many heritage schools throughout urban centres. Our project came in 2nd place in the elementary school division of the 2021 U.S. Department of Energy Solar Decathlon Design Competition.

The design preserves the school's historic brick masonry by insulating to the interior, adds a two-storey extension to the south, and creates a welcoming entrance via a sunlit atrium. Beyond addressing existing issues, the design is aimed at Toronto Green Standard Tier 3 performance standards, and achieves net-positive energy consumption.

The design highlights the use of mass timber with glulam and dowel-laminated timber in new construction, vapour-open masonry wall assemblies, and minimal thermal bridging across the building envelope. Design also minimizes water consumption with rainwater recycling from rooftops and permeable pavements, and wastewater recycling with an on-site Living Machine. The building specs mixed-mode ventilation via a dedicated outdoor air system (DOAS), supplemented by operable windows in all rooms. The large sports field allows for geothermal energy exchange; a ground-source heat pump sends heat to the spaces via radiant flooring throughout. Fan-coil units are installed in select spaces needing additional cooling. Photovoltaic (PV) panels are installed on the large roof and a parking shading structure, and building-integrated PV (BIPV) cladding is used for the extension facade, maximizing potential electricity generation. Excess energy is sent to the grid to generate additional revenue. All energy efficiency strategies throughout the design also function as learning opportunities for students to better understand and practice sustainable design.