Ask architect Alex Garrison of Gensler about environmental impact and he’ll tell you that the most sustainable building is the one you don't have to build.

That was the point behind Gensler’s adaptive reuse of a vintage data center in downtown Denver that’s now a sleek office tower called The Link. Using glass, reclaimed wood and recycled steel, Garrison led an effort that transformed a concrete-paneled, 1960s-era building, without tearing anything down. The result is a new, 12-story office building that uses 68% less embodied carbon than an identical new building on the site.

“A lot of people in our market typically will go in, buy a building and perhaps renovate the lobby on the inside,” Garrison, a Denver-based design director at Gensler, told LoopNet. “And this one was a much larger effort. And in fact, I would say in Denver, generally, this is new to the market, to do this scale of a renovation.”

The project offers a possible solution to scenes playing out across many cities, especially since the start of the pandemic: vintage buildings sitting fallow and threatening to stagnate a community’s central business district. The Link in downtown Denver takes its name from the building’s longtime owner and occupant CenturyLink, now known as Lumen Technologies. Garrison said the building once housed a fundamental node to the city’s internet infrastructure.

As part of its corporate consolidation, CenturyLink in 2018 put the 12-story, 230,000-square-foot building up for sale, with hopes that a new owner would transform the underutilized property. A team led by developer SteelWave, design firm Gensler and investment partner Rialto Capital Management acquired the building. The goal was to recast the amenity-free, mostly windowless data center into a vibrant mixed-use office building attracting tech tenants.

“If you start to look more closely where there may be older buildings that are seemingly left behind or [located on] streets that are not desirable … what can happen with projects like this is that they become catalytic" to transforming a street, Garrison said. “I think there are a lot of these types of buildings that are these sort of 60s-, 70s-, 80s-era buildings that could get [repurposed/rehabilitated].”

The development team established three goals to realize its vision. First, to completely reskin the building and give it a unique architectural identity. Second, to not only give The Link amenities, but “to create an amenity package for this building that was far greater than what is typical in the Denver market,” and reminiscent of a hotel, Garrison said. And third, to improve energy efficiency at the building, which hadn’t been improved since the 1960s, while still preserving the existing structure to reduce costs and reduce the new use of the site’s carbon footprint.

While more automakers are producing electric cars and more power grids are using clean energy, construction industry processes are still major hurdles to global decarbonization. The production, transportation and erection of concrete, steel, and aluminum all generate significant greenhouse gas emissions. Any building material that can be preserved is a material that won’t likely end up in a landfill. Building operations and construction combined are responsible for nearly 40% of annual global carbon dioxide emissions, according to a 2018 report from the International Energy Agency.

“I would say that from a [building material] perspective, I think there are really no things that you can exclude” in adaptive reuse, Garrison said.

As for new materials at The Link, Gensler primarily used glass.

There are light bulbs in the facade of the old gas and electric building next door to The Link. Gensler, which targets tech tenants at The Link, had a clever idea for its own facade: glazing the building’s new glass with three different reflectivity coatings. Now the building flashes different shades of color, mimicking a computer’s binary code that changes with the sun’s reflection. It’s also a design that, like its old gas and electric neighbor, pays homage to the building’s inhabitants, Garrison said.

Inside, reclaimed wood and Corten — or weathered, recycled steel with a warm, rust-colored finish — adorn the building’s ground-floor retail tenant: a coffee shop that turns into a wine bar at night. NanaWall folding glass windows help open the coffee shop to the street and make The Link’s glass facade more transparent. Meanwhile, a custom fireplace using fabricated Corten makes the building’s lobby extra cozy, Garrison said. Guests can play pool in the lobby, and SteelWave office managers pull double duty as building concierges on the ground floor as well, adding to the lobby’s hospitality.

Upstairs, custom trellis ceilings, made from reclaimed wood, hang above lounges outside meeting rooms. Instead of large conference rooms, The Link uses multiple, smaller meeting rooms to create more communal space inside The Link’s 19,000-square-foot floor plates.

The side of the building facing an alley previously had no windows, so the team added windows to bring in more daylight. The building also previously had no outdoor space, so Gensler created some by cutting off a portion of the roof and building a 12th-floor rooftop terrace adjoining a fitness center and indoor lounge.

The Link opened in April 2021, with SteelWave as its primary tenant.

The project wasn’t without its challenges, especially the pandemic, Garrison said.

“COVID-19 was a challenge,” Garrison said. ”Construction on The Link renovation began right before we here hit with the pandemic so when everything locked down except for essential workers, which included construction, we quickly adapted to a hybrid model where most meetings were over Zoom and in-person coordination was all done with face masks and hand sanitizer. The general contractor, Haselden, did an incredible job working within the safety protocols — shifting crews around to limit density and keeping the job site clean.”

Through adaptive reuse, Gensler was able to transform the building while reusing its core elements of steel, concrete and masonry. Other fixtures from the 1960s — like the building’s elevators, plumbing and heating systems — were also kept, thanks to minimal upgrades, Garrison said.

The former data center is now a prime downtown office tower with amenities desired by modern-day tenants.

The Link has an embodied carbon footprint of approximately 4.3 million pounds of carbon dioxide, roughly a third of the 13.5 million pounds that an equivalent new building would generate. In another effort to lessen the building’s negative impact on the planet, The Link has just as many parking spaces for bikes as it does for cars.

While prime downtown locations that command premier lease rates are the likeliest candidates for this kind of work, Garrison noted that “every built structure has possibility.

“By capitalizing on the already-built good structural bones all around us, we are afforded excellent opportunities to transform seemingly left-behind buildings into projects that embrace contemporary wellness,” he said.