How We Built It

Q&A: How Oxford built The Stack, Canada’s first new commercial Zero Carbon office tower

More than a decade in the making, Andrew O’Neil, VP, Development and Ted Mildon, Senior Director, Office Leasing, discuss the landmark Vancouver project

January 29, 2023
The Stack

Supporting our conviction in the long-term global demand for best-in-class workplaces that are healthy, smart and green, in 2010 Oxford acquired the downtown Vancouver site now home to The Stack. The Stack, which achieved occupancy in Q4 2022, comprises 555,000 square feet in a 37-storey tower, making it Vancouver’s tallest commercial building.

Featuring world-class design, the building’s soaring, ‘twisted-box’ form sets a new standard for architectural excellence, incorporating lush outdoor terraces throughout. Its form matched by its function, The Stack sets a new standard for environmental performance across Canadian workplaces, certified by the Canada Green Building Council (‘CaGBC’) in October 2022 as Canada’s first commercial Zero Carbon – Design certified office tower.

The tallest building to achieve Zero Carbon in Canada and the tallest office building in Vancouver, The Stack’s soaring height added significantly to the technical complexities faced in pursuing the Zero Carbon – Design standard. To illuminate how Oxford overcame these challenges, we sat down with two of the project’s leaders Andrew O’Neil, VP, Development and Ted Mildon, Senior Director, Office Leasing.

The Stack—Canada’s first new commercial Zero Carbon office tower

Q: What attracted us to the opportunity at The Stack?

Ted Mildon: Beyond givens such as value or location, we saw an opportunity to deliver what we thought the future of office would be to downtown Vancouver. We liked that the site would enable large floorplates, which fit with the West Coast tech influence that was emerging in the market, while possessing the scale and presence to attract a wide range of occupiers more generally.

Q: When did achieving Zero Carbon become part of the vision for the project?

Andrew O’Neil: Oxford has a longstanding commitment to sustainability and decarbonization. In 2015, we set a goal to reduce our carbon footprint 30% by 2025. By 2021, we reduced our carbon intensity by 37% from our 2015 benchmark, exceeding our target ahead of schedule.

In 2017, the Canada Green Building Council (CaGBC) released their Zero Carbon standard, one of the first councils to do so globally. We quickly partnered with them on two of our projects as part of their pilot program for this standard, The Stack being one of them.

TM: Building on Andrew’s point, achieving Zero Carbon aligned with our larger strategy to be a responsible investor and developer. But having legitimate third-party validation with a universal framework to work towards is critical. Being an industry leader in sustainability is an ongoing priority for us.

AO: Ultimately the certification is the culmination of over five years of planning to pioneer the CaGBC’s Zero Carbon framework in a high-rise and architecturally significant office tower, all while juggling the demands of realizing an economically viable commercial project for our stakeholders.

By being the first commercial high-rise office project in Canada to achieve this certification, we’ve garnered significant learnings that we can apply to future projects, and share with our peers, to drive the real estate industry to new levels of sustainability.

Q: What features were incorporated into the building to get to Zero Carbon? Did the building’s height make it more challenging?

AO: There’s certainly an increased degree of difficulty for dense, urban high-rise projects like The Stack to achieve Zero Carbon. Tall buildings generally have a lower ratio of roof area to building area, limiting the opportunity for on-site renewables such as rooftop solar. The Stack does feature a rooftop photovoltaic solar panel array, but we had to look at the building much more holistically to drive towards Zero Carbon.

In simple terms, there are two main drivers of a building’s Zero Carbon strategy. A) building envelope performance—that is, how can we invest in the outer shell of the building to reduce its energy demand? And b) building system design—for the energy that is consumed on site, how do we ensure we’re using the cleanest energy possible?

TM: From a building systems perspective, we’ve taken full advantage of BC’s low carbon grid —it is heated and cooled using electricity. Specifically, the heating system includes air source heat pumps with heat recovery.  This is a significantly different system design than even nearby MNP Tower which we completed in 2014. We are then able to supplement this all with rooftop solar.

AO: For the envelope, the goal is to reduce the building’s Thermal Energy Demand Intensity (‘TEDI’). We’ve done that through performance improvements including triple-glazed curtain wall with enhanced air tightness. We also have operable windows on the lower floors which allows us to provide ventilation to the building occupants without using electricity to run building systems.

The results speak for themselves. For Vancouver’s climate zone, the CaGBC set a TEDI target score (where the lower your score is, the better) of 30. The Stack’s TEDI score was 21, so we improved on the target by around 30%.

Q: What’s the reception been like from the market?

TM: The consistent feedback has been that we’re a leader in the market, and not by a little bit. For site tours with prospective customers, you can often judge engagement by time spent. Brokers and groups typically budget 15-20 minutes to go through a building, I’ve been asking them to budget 45 minutes to an hour, because they’ll need it.

When they see the rooftop mountain views everyone’s cameras come out. When we show them the 5,000 square foot gym and sauna, there’s inevitably a few wows. The pocket park, the premium casual restaurant by Nook, the hotel-like feel in the lobby—everywhere you go, people are impressed.

Q: What’s your biggest takeaway from the project?

TM: We’ve designed The Stack to still be great in 100 years, and it’s paid off. The Stack really reinforces the value of thinking long term, not just for tomorrow.

AO: One thing that stands out is just how much it’s resonated with our customers. And that’s really a reflection on the capabilities of countless teams across Oxford who brought The Stack to life, and the culmination of a lot of years of global, forward-thinking development experience.

Visit The Stack website->