The pandemic exposed a hulking problem in cities around the world. Last spring, when cities imposed lockdowns and companies were forced to send office workers home, office buildings were left unexpectedly empty. Built specifically for work and business, these massive buildings became essentially useless. And as companies plan post-pandemic futures with less office real estate and more of their employees working from home, buildings designed just for offices are veering toward obsolescence.
A radical new architectural concept offers a solution. Instead of designing buildings for specific purposes that may fade or disappear, architects and developers should create buildings that can accommodate a variety of uses, from offices to residential spaces to hotels to healthcare facilities. Towers should be designed to be neutral.
That’s the idea behind the unTower, a proposed use-neutral skyscraper concept from B+H Architects. A Toronto-based firm with 10 offices around the world, the firm has been designing skyscrapers for decades. And now, as part of the Singapore-based global developers Surbana Jurong Group, the firm has tower and mixed-use projects in the works across North America and Asia. Developed in conjunction with a team of engineers and vetted for its economic feasibility, the unTower proposal envisions a new type of structure that can house a wide range of uses and be easily converted when new needs arise.
Doug Demers, a senior managing principal at B+H Architects’ research and development-focused Advance Strategy practice, says the concept is about meeting the evolving demands of cities while also reducing the overall environmental impact of buildings themselves. “It’s important that when we’re building things that are going to last 50 or 100 years or more that they have the ability to flex and change uses. Because there’s a lot of embodied energy in building them, a lot of materials, and a lot of operation costs,” he says.
In addition to the energy and materials it takes to build them, buildings with short life spans are a huge source of wasted resources. More than 500 million tons of construction and demolition waste ends up in U.S. landfills every year, and when buildings are designed to be used for singular purposes, they’re more likely to be demolished and thrown out like garbage when their intended purpose changes or disappears altogether.
But turning an office tower into residences or anything else is not a smooth process. From the layout of floors to the lack of natural light deep inside, buildings designed to be offices aren’t easily convertible to something one might consider a comfortable home.
The unTower suggests a new approach. The concept is based around a simple doughnut-shaped building that has all its structural support at its interior and exterior edges, allowing the space within the doughnut to be configured for any type of use. Walls can be slotted in to divide the space into the rooms of an apartment or the separate units of a hotel, or removed completely for a large, column-free office. With windows outside and in, and the potential to add balconies or porches within the building’s atrium, the concept suggests a naturally lit building that could hold an office just as easily as a family home. “That’s the beauty of the doughnut,” Demers says.
Engineered in partnership with Coffman Engineers and Robert Bird Group, the unTower is designed around a simple, repeatable system of prefabricated beams that combine into a bicycle-spoke-like wheel for each floor. They can be made of composite metals and stacked into towering skyscrapers or built from mass timber for more sustainable mid-rise buildings. Demers says in addition to its ability to be reconfigured from the inside, the building’s structural system of parts helps it have an estimated life span that’s twice as long as a conventional building.
“The more you can componentize something, the more efficient it is to build and also to maintain and operate, because you’re not replacing entire pieces, you’re just replacing components over time as they wear out,” Demers says.
In collaboration with the construction and real estate development company Mortenson, B+H Architects did a detailed cost analysis on using this type of system on two projects, one in Seattle and another in British Columbia. Taking into account construction costs and the potential for the towers to be reused for different purposes over time, an economic analysis found that an unTower project would cost the same amount as a conventional tower building. Add in the potential higher rents for these more easily reusable spaces, the faster timeline of constructing a component-based building, and the estimated lower operating costs over its life span, and the unTower could be a financially viable competitor to the typical skyscraper.
Demers says these benefits are attractive to developers, and his team has been in conversations with major developers like Tishman Speyer and Hines about exploring the unTower concept, and the Surbana Jurong Group is likely to explore using these ideas in future projects.
Demers says the concept is just the starting point. Whether it takes form as a doughnut-shaped tower or some other type of building, he argues that the concept of neutrality and flexibility in the building’s use is a key idea that will only become more relevant over time. “I think any developer post-pandemic is going to be thinking about resiliency in anything they build,” he says. “If you build something that has flexibility and resiliency, it can have many uses in its life, and that is quite a bit more responsible and sustainable.”