Getting Back to Nature with Mass Timber
Editor’s Note: This article is reprinted with permission from PCL. For more valuable articles, insights, and resources, visit: https://www.pcl.com/ca/en/insights
Generations ago, our ancestors built their homes out of large wood timbers. Handmade log cabins popped up across North America, exhibiting craftsmanship, warmth, and rustic charm.
As time passed, though, building materials evolved. Concrete and steel formed the foundations of homes and buildings across the continent. These materials were sturdy, widely available and less labor intensive to prepare, allowing structures to rise from the ground faster.
But all that efficiency comes at a cost. Manufacturing concrete and steel is energy-intensive and, as the world strives to reach net-zero carbon targets, the need for alternative building materials is increasing.
Wood is an excellent option for those looking at alternative building materials. It’s an environmentally friendly, cost-effective, and renewable material that has come a long way from the days of log cabins. Wood also plays a key role in sustainability through biodiversity and forest conservation.
As more and more of our clients look toward sustainability and carbon neutrality in their buildings, PCL is leading the way in the use of mass timber on large-scale construction projects.
Benefits of mass timber
‘Mass timber’ refers to structural building components made from wood – including large panels, posts, and beams – that are glued under pressure or nailed together in layers. The wood’s grains are stacked perpendicular to enhance its strength-to-weight ratio. This leads to other structural efficiencies.
“You have smaller foundations, which is driven by the lower weight of the structure, and you also have lower forces of seismic resistance,” says Ankit Sanghvi, director of preconstruction and estimating and a mass timber expert with PCL’s Denver office.
There are many other benefits to building with mass timber:
- Accelerated Project Delivery: Mass timber is ideal for prefabrication and modular construction. This can result in schedule acceleration, reduced traffic and fewer workers needed on a job site.
- Carbon and Waste Reduction: Wood naturally sequesters carbon and requires significantly less embodied energy to manufacture and install compared to concrete and steel.
- A Solution for Constrained Sites: Prefabricating with mass timber off-site can shorten timelines, improve safety, reduce site congestion, and mitigate against bad weather.
- Enhanced Aesthetics: The warmth and quality of exposed timber can positively impact our well-being and reduces the need for additional finishes, further reducing waste and embodied carbon.
Mass timber is catching on so much that it was declared the 2022 Design Trend of the Year by STOREYS, a real estate news website. But at PCL, we’ve been working with mass timber for two decades and have more than 65 wood-based projects across North America under our belts. Our mass timber experts are constantly driving innovation to deliver the best possible results for our clients.
Reaching for the sky in Toronto
Currently under construction, Limberlost Place will soon rise to be a shining beacon of sustainability at George Brown College’s Waterfront campus in downtown Toronto. At 10 stories, it will be the tallest mass timber structure PCL has built and the first of its kind in Ontario.
Fittingly, Limberlost Place will be home to the Brookfield Sustainability Institute, GBC’s School of Architectural Studies, and the School of Computer Technology. It will also house a fitness center and a child care facility, and it will feature large, open study spaces for students.
As GBC says on its website: “Students will learn in and from this flexible and future-proof facility, equipped with networked and adaptable smart building systems designed to adjust to changing academic uses.”
Limberlost Place will be able to operate passively for half of each year, will run with no fuel-fired systems and will generate nearly a quarter of its energy needs through solar panels mounted on the roof. It will operate well below environmental intensity standards set by the City of Toronto for energy use, thermal demand, and greenhouse gas emissions.
PCL started construction in August 2021; the building is expected to be ready by fall 2024 and will open for classes in January 2025. “The pace and progress of construction is really swift as the installation of the mass timber pieces moves very quickly,” says Nerys Rau, GBC’s project director for Limberlost Place. “It was incredible to witness the placement of the three-story timber columns; one of the columns is currently the largest in North America. It’s fascinating to see how these massive elements are installed with such incredible precision.”
Achieving mass timber goals in Denver
In Colorado, PCL completed the Burwell Center for Career Achievement at the University of Denver in 2020, making it the first 100 per cent mass timber structure in the state. With 21,000 square feet of space over three stories, it serves as a central hub for the DU community and facilitates student career development, alumni engagement, student employment, and employer connections.
To turn DU’s vision into reality, PCL worked collaboratively with the design team and subcontractors starting at the schematic design phase. PCL led the extensive coordination of building systems routing, achieving our goal of having no exposed conduit within the building despite having over 70 per cent of the mass timber structure exposed. We also self-performed the installation of the mass timber structure in addition to the concrete foundations, giving us more control over the quality and schedule of the project. This allowed the cross-laminated timber core walls and mass timber superstructure to be erected in a blistering 28 days with a crew of only six craft workers.
The Burwell Center is LEED Platinum-certified with energy performance 60 per cent below the baseline for similar buildings. A large array of solar panels on the sloped roof structure provides much of the building’s electricity needs. The total volume of wood used in the Burwell Center is grown within U.S. and Canadian forests. The trees regenerate quickly and removed 417 metric tons of carbon dioxide from the atmosphere, showcasing the sustainable nature of this rapidly renewable material.
Innovation comes to life in Prince George
Northern British Columbia is the heartland of Canada’s forest industry. So, it’s only fitting that one of PCL’s first mass timber structures was built at the University of Northern British Columbia in Prince George. Completed in 2014, the Wood Innovation and Design Centre (WIDC) at UNBC has more than 49,500 square feet of space over six stories, including classrooms, research facilities, a lecture theatre, offices and student spaces. It’s home to UNBC’s Master of Engineering in Integrated Wood Design program, which aims to equip students with the knowledge needed to lead the way in sustainable building into the future.
The WIDC was designed with an ‘end-of-life story’ in mind – UNBC’s vision included being able to disassemble the building at the end of its functional life and reuse the wood products. The building was designed so it could be easily replicated, hopefully encouraging architects, engineers, and developers to build similar structures. It was also built using tree varieties found in British Columbia – including Douglas fir, cedar, hemlock, pine and spruce – and engineered wood products manufactured in the province.
Mass timber has an enormous potential to lower our clients’ carbon footprints and help them meet their sustainability goals. As mass timber construction continues to evolve, PCL will continue to be at the leading edge of incorporating this innovative building material into projects. We’re willing to look to the past to plan out a more sustainable future.
PCL is a group of independent construction companies that carries out work across the United States, Canada, the Caribbean, and in Australia. These diverse operations in the civil infrastructure, heavy industrial, and buildings markets are supported by a strategic presence in 31 major centers. Together, these companies have an annual construction volume of more than $6 billion USD, making PCL one of the largest contracting organizations in North America. Watch us build at PCL.com.