Demolishing an existing structure means wasting all the energy that was invested in creating its materials. Destruction requires energy, and the waste material must be taken to landfills. Add that to the energy and emissions required to make, transport and assemble the materials for a brand new building, and it’s easy to see how using what’s already been built is a more environmentally sustainable option.
Susan Piedmont-Palladino, director of the Washington-Alexandria Architecture Center at Virginia Tech, spoke to WIRED from the office building that embodies this premise. It was built in 1909 as a girls’ primary school. “The building is brick, but the floor structure is all timber that would have been cut down in the early 20th century,” she says. “I’m sitting here in this building with that carbon locked up and useful. If we were to tear it down, all this stuff has to go to landfill or reclamation.”
It is now possible to quantify the metric tons of carbon that can be saved by not rebuilding from scratch, which can help convince clients or planners to choose a greener option. Most architectural and engineering firms now have access to software such as OneClick LCA or EC3 that can simulate scenarios for reusing existing materials and structures in a new project. This software can also be used to estimate the financial value of old foundations, concrete, aluminum, wood and other materials and plan how to incorporate parts of an existing structure. If the structure cannot be saved, sometimes the materials can be reused – one type of concrete can be broken up and made into another style of concrete, for example.
“This is getting closer to common practice,” says Christopher Pyke, senior vice president of the American Green Building Council and a professor of urban planning at Georgetown University. “It’s been a fundamental part of the LEED rating system for the last five years, and in Europe it’s being codified in regulation.” LEED plaques on shiny new buildings can now reflect that not everything about the new construction is new, or that the structure is completely repurposed from an old building.
One concept embraced by some European architects views buildings themselves as material banks — structures that store and preserve materials for future use. Some buildings are designed to be easier to demolish in the future so that materials can be easily accessed for new projects.
Piedmont-Palladino, while intrigued by material banking, is more compelled by the reverse idea—building for long-lasting but adaptable durability. Making architecture more sustainable requires changing people’s mindsets, she says, and resisting the lure of shiny green balls.
“The architecture very quickly tore it down and made it new. The more people associate architecture with trends and fashion, the more dangerous it becomes. It’s the same thing with urban design,” she says. “You are not the last people to be involved in this building.”
Take the final project of Ludwig Mies van der Rohe, who is one of the most important architects of the 20th century, but whose popularity has faded. He created a modern, minimalist “skin and bones” style that shaped American urban landscapes for the last 25 years of the 20th century. Martin Luther King Jr. Library in Washington, DC, one of his final projects, was not completed until three years after his death in 1972.
“It went through a reputational decline in the stock market. Everyone loved him, and then everyone hated him,” says Piedmont-Palladino. In the early 2000s, the library was employed and reviled by borrowers and librarians for its dark, cramped and unusable spaces. When the library system finally asked for proposals for renovations, many in DC called for it to be torn down and rebuilt from the ground up. Piedmont-Palladino, on the committee to select new architects for the project, was one of many who objected, both on sustainability and aesthetic grounds. “My, he’s hard to love. But did we really want to tear down this project that represented modernism coming to Washington?”
In the end, they didn’t. The library, which reopened at the end of 2020, looks shiny and new. The architects added wood, curves, windows and sound, making the place warm and beautiful rather than austere and intimidating. But the structure retains its Miesian facade, its history – and its embodied carbon.