| Limberlost Place | |
| Former Names: | The Arbour (2018–2021) |
| Address: | George Brown College Waterfront Campus;185 Queens Quay East, Toronto, Ontario, M5A 1B6 |
| Country: | Canada |
| Owner: | George Brown College |
| Type: | Institutional (education): School of Architecture and Computer Technology |
| Capacity: | 3,400 students and staff |
| Dimensions: | Height: 172 ft/52.50 m10 stories |
| Built: | Under construction |
| Architect: | Moriyama Teshima Architects, Acton Ostry Architects |
| Builder: | PCL Construction |
| Structural Engineer: | Fast + Epp Structural Engineers |
| Services Engineer: | Mechanical/electrical engineers: Introba (previously Integral Group) |
Limberlost Place, formerly known as The Arbour, is a new addition to George Brown College's Waterfront Campus. It is set to open in summer 2024, and will be home to the college's architecture and computer technology students.[1] With a planned occupancy for nearly 3,400 users, the 225,000 square-foot building will feature classrooms, study areas, staff support spaces, and a daycare facility.[2] The is project designed by Moriyama & Teshima Architects alongside Acton Ostry Architects.
Limberlost Place features low carbon and high-efficiency qualities, which surpass TEDI, TEUI and GHGI targets. Limberlost Place's high-performance envelope and passive systems render it a self-sufficient and sustainable structure. The building makes use of mass timber, a known renewable material and has brought forth new research and attention to the field of mass construction.
Limberlost Place's form is influenced by the use passive design techniques and uses decentralized mechanical systems to control its environment. Its northern facing façade is used to maximize sun light, while heat is captured from the south. The peak of the building, gives way for solar photovoltaic panels to generate energy for use throughout the building, and also contributes to the exchange of air. Depending on atmospheric condition readings sent by its weather station, automated windows controlled by the building's operating system are opened and closed when needed. Through the use of the stack method, air entering the building is guided through transfer grills lining the corridor, and forced to exit out through the east and west, eight-story solar chimneys. The building's top two levels are served through cross ventilation, with air entering the building through manually controlled windows in classrooms and offices, then traveling through hallways and exiting through the solar chimneys. Deep-water cooling is an additional ventilation system implemented in the building's design. Water pumped from the neighboring Lake Ontario circulates throughout the building to cool it down.
One of the sustainable strategies employed in the building's design is the use of green materials. Mass timber members, used for floor slabs and vertical supports, make up its primary structure.[3] In line with environmental sustainability principles, wood is a natural, renewable material that can be reused or recycled at the end of its life.[4] In addition to its renewable quality, wood has low-embodied energy, contributing to reducing the building's greenhouse gas emissions.[5] Made from Black spruce harvested from Quebec forests, sustainable material sourcing was implemented in procuring the timber used for Limberlost Place's construction.[6] The building's proximity to its wood source also makes for a low carbon footprint, ensuring minimal negative environmental impact. Through projects such as this one, the Canadian government has made efforts to further implement the use of wood as a construction material by reason of its carbon sequestering capacities.[7] Through initiatives such as the Green Construction through Wood (GCWood) program, the use of mass timber is promoted as a favorable, green material option for all construction projects throughout the country, as part of Canada's efforts to meet its greenhouse gas emission reduction objectives.[8] Limberlost Place is among the mass timber buildings financed by the GCWood program.
The exterior of the structure is encased in prefabricated panels spanning 11.7 meters in height and 4.2 meters in width. The panels were constructed with a building tightness of 0.4 L/sm2 at 75 Pa, exceeding its original target. Testing conducted by the Underwriters Laboratories of Canada revealed it performed more than double in efficiency. The building's walls consist of around 40% windows, placed almost consistently 3 meters apart, and allow for the building to be expanded with the use of demising walls for future projects. Large spanning curtain walls were designed to capture waterfront views and engage with Limberlost Place's surrounding community.
An enclosed bridge was also added to the structure, connecting Limberlost Place to the existing George Brown Daphne Centre for Health Sciences. The triangular truss design of the elevated bridge provides an alternate path of travel through its adjacent campus buildings.
Along with a steel core, mass timber components make up much of Limberlost Place's structure.[9] The 10-story building features some of the continent's largest mass timber columns, standing at 3 stories tall. Column-free classrooms were designed, allowing the use of partition walls to accommodate different programs, as well as maintain unobstructed views of the waterfront. The construction process of these mass timber components began off-site, where cross-laminated timber (CLT) slabs were prefabricated, before being brought to site for installation.[10] Totaling 1,190 CLT and 571 glue-laminated components, each were organized according to their designated location within the building's structure, and brought to site for efficient assembly.
Fast + Epp Structural Engineers achieved a structure void of conventional beams, by designing a floor system made up of 7-ply CLT panels spanning north-south, with thinner CLT panels spanning the opposite direction. The slab of CLT panels is reinforced by a concrete topping, with the floor system resting on glulam columns. This system eliminated the need for beams, while also allowing 9.2 meter spans. Through these features, Limberlost Place has achieved the highest level of municipal targets amongst Toronto buildings, meeting Tier 4 of the Toronto Green standard.
Though mass timber construction is not a new concept, it has not yet been used for an assembly occupancy building of this height. As the first building of its kind in Ontario, obtaining proper permits proved to be an issue throughout the design and construction processes, as Limberlost Place exceeded the six-story height allowed by the Ontario Building Code for timber construction.[11] Through meetings with jurisdiction authorities, the required permits were obtained and construction began. Soon after, Limberlost Place's design began to alter national and provincial building regulations. As of July 2022, mass timber buildings can be constructed up to 12 stories high— double the previously regulated height.[12]
Following Limberlost Place, downtown Toronto is seeing the addition of similar buildings. Just around the corner from Limberlost Place is T3, another mass-timber building currently in the final steps of its construction. The project has also resulted in numerous research publications, contributing to furthering large-scale mass-timber construction in Ontario.