Building tall buildings out of wood instead of steel offers a lot of benefits, most notably that it considerably cuts the carbon footprint of new construction. But the properties of wood mean that all-wood buildings have a height limit, after which wood isn’t a feasible construction material. A prototype from Toronto-based architecture firm Dialog gets around that by combining mass timber (solid wood panels nailed or glued together, the basis for tall wood buildings) with steel and concrete, plus solar-panel lined walls and an in-building algae bioreactor, for a 105-story skyscraper that would have no carbon footprint.
Craig Applegath, founding principal of Dialog, says they were inspired to create the prototype because of the “ticking time bomb of climate change,” plus the fact that wood stores carbon and, when sustainably harvested, is better for the environment than steel or concrete. But wood doesn’t have the same structural capacity as steel or concrete, meaning tall all-wood buildings would basically need a lobby completely full of support columns.
“The race for tall wood is sort of foolish,” he says. “It’s not the best use of the material, so we said, ‘what do we do? How does wood figure into tall buildings in a way that’s economically viable?'” The answer they came up with was to use cross-laminated timber in the floor system, which accounts for 70% of all materials used in a high-rise building. The project, which Dialog calls a zero-carbon hybrid timber supertall prototype, is the winner of the architecture category of Fast Company’s 2021 World Changing Ideas Awards.
The prototype includes solar panels on three facades to generate 25% of the building’s electricity. A natural gas system provides the rest of the heat and power, but an algae bioreactor eats those carbon emissions, for a tall building that produces zero operational carbon. Applegath admits he wasn’t always a fan of tall buildings, but he realized they’re necessary, especially in Asian cities where the only room to build is up. “If we’re going to have to go up, let’s figure out how to do it in an environmentally responsible way,” he says. “There are places in the world where tall buildings are the right solution.”
Since first unveiling the prototype, the hybrid timber floor system is now patent pending, and Dialog is working on figuring out how to economically manufacture it, so it’s something developers will actually purchase. They’re also working with a developer who is testing out the system. By making the prototype on their own, they’re proving environmentally friendly buildings are possible, spurring developers to invest in this future. “If you want to push the envelope, you can’t just do what the market is demanding of you,” Applegath says. “You have to step outside the market, take some risks, and the market may follow you.”