Limberlost Place at George Brown College

Moriyama Teshima Architects (MTA) and Acton Ostry Architects (AOA)

Short description

Moriyama Teshima Architects in collaboration with Acton Ostry Architects, have designed the innovative and ambitious Limberlost Place, currently under construction at George Brown College’s Waterfront Campus in Toronto, Ontario, Canada. The project combines design and structural innovation with advanced prefabricated tall building façade systems, as well as an optimized use of decentralized mechanical systems working in consort with passive systems, to produce a building that is the healthiest environment for both its users and for the planet. This building is composed of a mass timber structure, and achieves the highest levels of our municipal targets, well in advance of the 2030 TEDI, TEUI, and GHGI reductions.

The aspirational design has introduced mass timber into the Toronto lexicon of public buildings and will achieve sustainability targets well in advance of the city’s step plan to 2030 carbon reductions. The higher education facility’s exposed mass timber in a space where the assembly occupancies and the teaching spaces occupy the full verticality of the building, as well as the exceptionally efficient, prefabricated envelope system, make it unique.

Limberlost Place is organized around a 3-bar plan whose dark programming, cores, services, and vertical circulation, occupy the middle bar protecting the perimeter for classrooms and breathing rooms. The result was a “beamless” system that could maximize space and access to daylight while reducing artificial lighting loads in the occupied areas. Fast + Epp Structural Engineers created a 3-component mass timber solution that is extremely shallow for this span, with a system that is comprised of bespoke glulam columns and main CLT/concrete composite spanning elements called “slab bands”. The connections to concrete were the subject of testing conducted in collaboration with the University of Northern British Columbia and Biberech University of Applied Sciences in Germany. This research, which is publicly accessible through Natural Resources Canada (NRCAN), has further advanced the industry’s collective understanding of timber concrete composite systems and the connection details between the two materials.

The prefabricated envelope incorporates a natural ventilation system through both powered and manual operable windows. A rooftop weather station sends wind speed, air quality, and temperature readings to the building operating system to control the opening and closing of the windows when appropriate conditions arise. During passive mode, air will travel through operable windows into classrooms, offices, and meeting rooms, then into the corridors through acoustically lined transfer grilles where the air makes its way into the east and west solar chimneys. Stack effect then pulls the air through the solar chimney to 1.5-storeys above the highest occupied floor and vented out the roof. When the system is in passive mode, mechanically operated ventilations systems shut down, reducing energy usage.

Limberlost Place’s utilization of a prefabricated envelope system resulted in many benefits, including, enhanced design assist opportunities, greater quality control (as the panels themselves are constructed in a conditioned and well-monitored environment), reduced construction, and full system warranty. Paired with the mass timber structural composition, these two systems exploit just-in-time principles for a quiet and clean job site that minimizes neighbourhood construction noise and disruption.

Prior to this project, the maximum storeys for a tall wood building in Ontario was 6. For Limberlost Place to have been approved for construction, while maintaining its proposed 10-storey design, provincial building code requirements were changed. By preserving the 10-storeys and officially attaining “tall wood building” status, the project also became eligible for funding—the Green Construction through Wood Program offered by NRCAN. These funds financed the rigorous testing which took place to prove that structural systems, technological innovations, and fireproofing worked as needed.

One of the primary elements contributing to the sustainability of the project is the form of the building. The significant roofline peak is derived from 3 major sustainability measures:
1. The east and west façades of the building act as passive solar chimneys allowing fresh air to be drawn from operable windows in classrooms and offices, through the corridors and then out to the solar chimney at each floor. This solar chimney starts on the second floor and continues up above the building roof creating a non-fan enabled stack effect and becomes part of the architectural profile.
2. The building stretches up to the north to maximize the north light to the upper floors and slopes to the south to minimize heat gain on the upper floors from the south.
3. The slope becomes a natural armature for the solar PV, utilizing attachments to the standing seam roofing rather than a full secondary armature to create the slope.

The team’s hope is that once Limberlost Place is complete and occupied, the inhabitants will be influenced by the visible intuitive operations, use of renewable materials, and low- and high-tech approaches to sustainability. Placement of social spaces near and within the places where the passive systems and sustainable features are located, provides immersive opportunities where staff, educators, and students are exposed to naturally ventilated, day-lit, innovative spaces, creating the potential to change expectations broadly in our community. Buildings themselves cannot change the future trajectory of how we build sustainably, nor does this rest solely with designers and builders, but rather with building’s occupants that will raise expectations and demand change.