Gensler, an architecture and design firm, renovated its Washington-based office to create a private terrace that opens the office’s second floor to the outdoors.
Collaborating with DPR Construction, carpet manufacturer Tarkett and biotech company Mycocycle to naturally break down broadloom carpet waste and avoid the landfill, the team diverted 90 percent of the construction and demolition waste by having a deconstruction, reuse and recycle plan for materials.
The team approached the project with sustainability as a priority, hoping to reuse as much waste material as possible. The project began between April and May of 2023, says Ethan Hartman, DPR Construction senior project engineer, with DPR wrapping up its contributions in October 2023.
Construction details
The first phase of the project was demolition. At its core, the project was a terrace addition, Hartman says, but it also included a partial renovation of the space.
On day one of the project, DPR Construction, headquartered in Redwood City, California, started by separating the construction area from Gensler’s active office space. The demolition phase began with the team removing conference rooms and making other structural modifications.
“There were modifications to a large soffit design on one of the floors,” Hartman says. “Basically, we were stripping the space down to its shell as much as possible.”
The space was going from an alley to a terrace, he says. DPR put in structural steel and other structural elements to support the increased load. The team then cut an opening on the side of the building, allowing entry from the inside space to an outdoor terrace.
Hartman says they had to make additional structural modifications to install the project’s glass operable wall. This was done while also doing the interior fit out and making interior and exterior modifications.
The terrace expansion began in 2023 and was completed in mid-2024, providing approximately 6,000 square feet of indoor-outdoor space, says Hansoo Kim, a Gensler design director and principal.
Reusing materials
Knowing that the goal was to reduce as much waste as possible, Hartman says the team made sure to review anything that was deconstructed to decide how to reuse or recycle the material.
“There were some things that we knew ahead of time we were going to reuse,” he says. “There was a wood paneling finish and brick we knew we were going to use. Outside of those identified things, it was just every day determining what could be done, what could be reused from the materials, and then if it couldn’t be reused, sending it to be recycled.”
At least weekly, Hartman and the DPR team would walk through the deconstruction progress with Gensler designers and Benjamin Holsinger, Gensler sustainability director, to discuss the reuse of materials.
Interior recycling
The deconstruction phase still produced materials that were unable to be reused; however, many of those materials were suitable for recycling, including the drywall, stud framing, in-wall insulation, glazing and metals from electrical wiring, jacketing and support brackets, Hartman says.
“There were glass walls that we were able to recycle, so we converted what was a glass wall into a glass railing,” he says. “We recycled that portion of the glass that was the wall, and then there were some other materials that we both reused and recycled.”
Hartman says a lot of the plywood removed from the flooring and ceiling construction was recycled. The team also reused some of the plywood throughout construction and in the project’s final condition, installing it into the finished walls and ceilings.
The team also disconnected entire runs of duct from the units, detached them from the ceilings and put them back into the ceiling following the new structural additions.
“That was a really fun process,” Hartman says. “Taking that down, storing it and then putting it back up at the end of the project.”
Exterior reuse
The project space previously had been an alley that housed small condenser units for air conditioning throughout the building. Hartman says it had old stone ballast, which left small pebbles throughout the roof that DPR was able to reuse and recycle.
“The terrace area was split into three areas,” he says. “We kept a third of the roof for that mechanical utility area, a little bit more than a third for the terrace, and then we had a green roof, as well.”
In the utility space, the team reused some of the stone ballast by bordering the edge of the green roof with the repurposed stone.
The brick that was removed to create the opening on the side of the building was saved and reinstalled along the edge of the opening, according to Hartman.
The space had a large amount of wood paneling that was removed from the ceilings and walls, which was reused in the new configuration of the ceilings and walls. Hartman says they almost reused the wood paneling entirely, recycling and donating the leftover material at the end.
“The recycling rate was at 85 percent, and then material reuse and carpet diversion through Mycocycle got us to the above 90 percent total waste reduction,” he says.
Power in mushrooms
The team faced one main recycling roadblock during the project: broadloom carpet.
Rachel Palopoli, director for circular economy at Tarkett, a flooring company with North American headquarters in Solon, Ohio, says not many people want to recycle commercial broadloom as it doesn’t have a lot of value when it is later deconstructed.
Mycocycle, which is based in Bolingbrook, Illinois, leverages the root structure of mushrooms to break down construction materials. The fungal root structure, mycelium, transforms challenging materials into clean and usable, biobased raw materials.
Palopoli says she and Mycocycle founder Joanne Rodriguez came in at this point in the project, though mycelium was not guaranteed to work on broadloom carpeting.
Palopoli, Rodriguez and Holsinger were having dinner when Holsinger brought up the project’s broadloom carpet, Palopoli says.
“I looked over at Joanne, and I’m like, ‘What if we do a pilot? Why don’t we try and see if it works?’” Palopoli says. “So, we nicknamed the project the magic carpet ride.”
Gensler and DPR already had begun the project when they ran into the broadloom carpet challenge. Palopoli says it was helpful to see how passionate each company is about sustainability.
“By December 2023, we had picked up the carpet from Gensler’s office, did what we needed to do, such as downsizing the carpet to go through the Mycocycle process,” she says. “Then it was completed.”
The success with the broadloom carpet helped the project reach a 90 percent diversion rate and led to a partnership between Tarkett and Mycocycle.
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