A rendering of Limberlost Place, a new 10-storey facility for George Brown College in Toronto. HO-Doublespacedoublespace photography/Supplied
Sometimes change is hard to spot. Limberlost Place, a new 10-storey facility for George Brown College, lands quietly on Toronto’s eastern waterfront. Its serrated, copper-hued facades rise up and slim to a peak with just a hint of bravado.
There’s no sign this is among the country’s most innovative buildings – not until you cross the threshold. The main lobby rises in a grand staircase framed by ten-tonne columns and nine-metre-long beams of black spruce.
For mass timber, as those engineered wood products are known, this is state of the art. Designed by Toronto’s Moriyama Teshima Architects (MTA) and Vancouver’s Acton Ostry with engineers Fast + Epp, Limberlost stretches building codes and gives architects and engineers a new system of open-sourced solutions.
“Building Limberlost was like landing a personal moon shot,” says Carol Phillips of MTA, who describes this as the most complicated project of her career.
The work of the design team delivers a visceral result. All the spruce fills the main rooms with a log-cabin coziness; it even smells good, an agreeable woody tang. The heft of the glue-laminated columns meets fine strips of oak that delicately cover the walls. “It’s like a tree sending out branches,” MTA’s Phil Silverstein says, “the great bulk beside something much smaller.”
Light filters in through wood slats, and fresh air comes by way of operable windows and two nine-storey solar chimneys that drive passive ventilation. The building is designed to deliver net-zero carbon emissions. Along the way up are “breathing rooms” – small social and study spaces with quieter acoustics. Classrooms open to daylight and show just enough wood to remind students that structure and surface can be the same thing. At the top of the building, a shared event space tucks in under the beams of the roof, enjoying views over Toronto and the blue expanse of Lake Ontario.
Wherever possible, the architectural team left the wood of the walls and structure on display. Knots, scars and seams are visible, not concealed – celebrated with washes of gentle light and bursts of candy-coloured furniture. For Ms. Phillips, the timber has a lesson. “There’s so much pressure on young people to be perfect,” she reflects, “and to be surrounded by something like this, it’s got to help you understand the beauty of your uniqueness and the beauty of the so-called imperfections.”
For George Brown, a college with programs in architectural technology, this was a heavy lift. In 2018, they launched an invited design competition for the building; among the entries was a curvaceous glass-and-steel half dome from Pritzker Prize winner Shigeru Ban. MTA and Acton Ostry won the day with their more modest proposal.
Limberlost’s mechanical system employs natural ventilation – hot air rises through huge chimneys – along with hyperefficient displacement air systems. HO-TOM ARBAN PHOTOGRAPHY INC
Nerys Rau, the college’s director of design and construction, says George Brown explicitly wanted the building to perform double duty as a case study. The building houses classrooms for the college’s School of Architectural Studies and its Brookfield Sustainability Institute along with offices for the college’s executives. The ground floor houses a daycare with a small outdoor playground.
“We wanted this to be a building that our students could learn in and learn from,” Ms. Rau said, “but also that the industry could learn from.”
Innovations are everywhere. “This is a building that pushes the envelope in every direction,” says Milos Begovic of Acton Ostry, who worked on the project along with colleague and mass-timber advocate Russell Acton. A bespoke structural system knits horizontal beams into the floors, reducing the bulk of the wooden components and keeping the building’s dimensions tight. In addition, Limberlost’s mechanical system employs natural ventilation – hot air rises through huge chimneys – along with hyperefficient displacement air systems. These deliver gentle streams of air at floor level, and the air is heated and cooled by radiant panels above, their temperature moderated by flows of water. This all-electric, gas-free system, supplemented by deep-lake water cooling, is designed to generate zero carbon emissions.
In all, Limberlost can hold 3,400 people. That scale and combination of uses posed huge technical and bureaucratic hurdles. The design team had to prove that their wood creations would safely cradle all those people. Often, regulators don’t adequately recognize the difference between ordinary wood construction and mass timber. Regular wood framing – what professionals call stick-built construction – uses many small pieces of lumber to make frames that are strong but can, under the wrong circumstances, burn.
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Mass timber is different. At Limberlost the key components are cross-laminated timber (CLT), slabs of wood made from many smaller pieces that are interlocked and adhered with special glues. In a fire, these are similar to solid wood. Imagine trying to start a campfire by putting a match to a foot-thick log.
Moriyama Teshima Architects' Phil Silverstein says the project was guided by a problem-solving approach.
Robert Jackson, a partner at Fast + Epp who led the structural engineering of the building, explained that most tall timber buildings have so far been limited to housing or offices. These buildings hold relatively smaller numbers of people, and they are full of walls. “In the event of a fire, you are contained in your own bubble,” he said. Limberlost, in comparison, has large classrooms and assembly halls, several of which are connected to each other by open stairs.
“To see a 10-storey academic building in mass timber is quite a lift,” he said. “When there’s more people, there’s more risk. When there’s more height, there’s more risk.”
Students shouldn’t worry. In the end, the engineers and architects agreed with the building-code examiners that the building is abundantly safe. One trade-off was that much of the wood structure was covered with drywall – a compromise with building-code examiners that should prove to become less necessary as this technology becomes more readily available.
And that was the point of this project. “Egos were checked at the door,” Phil Silverstein said. “The trades, the architects, the engineers, the owner, the constructor – we all just saw ourselves as a group of problem-solvers trying to find clever, innovative solutions and keep the beauty alive.”
They did. Limberlost is not a spectacle but a demonstration, a building that shelters its community while testing the limits of what wood can do. Look closely, and you will find architecture that warrants celebration.