For three years, the 250,000-square-foot hospital on Balsam Avenue went untouched. Lights, doors, toilets and medical technology sat quietly inside, ready to be bulldozed and sent to landfills.

City officials knew they couldn’t leave up the massive beige block of a building. The structure, abandoned when its owner decided to consolidate at a different location, didn’t fit into the walkable neighborhood residents wanted at Balsam and Broadway. In trying to convert the hospital for other use – where occupants could get some sunlight, ideally – they knew they would end up taking most of it down anyway.

So the building had to go: all 65 million pounds of it. But where to?

By and large, not the dump. Instead, some of those materials are in the foundations and structures of new city buildings. Others are housed on-site or at resale stores, ready for reuse. The ex-hospital is one of the first major commercial deconstructions in the United States, under the strict conditions sustainability advocates have set for themselves.

Who in their right minds would try to recycle 65 million pounds of old hospital? Enthusiastic sustainability officials, who also happen to be compelled by law. The Boulder City Council approved mandates, effective 2020, to divert 75% of home and commercial structure removal waste from landfills.

The brick-by-brick deconstruction of Boulder’s former five-story community hospital is an early test of a policy idea quickly spreading across Colorado and other recycling-hungry states. Sustainability officials estimate about 35% of current landfill waste statewide is from construction debris; Boulder wants to divert 85% of all formerly landfilled waste by 2025, so finding alternate destinations for old, heavy buildings will be key.

The sustainability movement is also working hard to draw attention to “embodied carbon,” or the climate-damaging carbon dioxide that has already been unleashed upon the world in the forging, shaping and transporting of construction materials used in a building. Plunking a 30-year-old steel beam into a new building’s frame is a victory.

It’s not an airy wish. Places like Boulder demand it. Even if it’s door by door, wire by wire.

And in the hospital’s case, it was. Every object, from a fist-sized chunk of drywall to a two-ton steel beam, was weighed on site. Millions of pounds of concrete and brick were crushed on-site and placed carefully back into the ground, to serve as the foundation of an affordable housing project that will occupy the now-vacant lot.

Some of the steel beams are now holding up relocated Fire Station No. 3 at 30th Street and Arapahoe Avenue. Other steel beams sit in the former hospital parking lot, their size, density, tensile strength and exact geolocation coordinates cataloged in spreadsheets for buyers to pore over.

To teach future generations, Boulder officials even wrote down the brand of permanent paint marker they used to identify each steel beam: Mighty Marker, by ARRO-MARK Co. LLC.

While engineers are still checking the math, Boulder is declaring success. Just over 60.8 million pounds of the hospital were reused or recycled. Only 4.2 million pounds went to a landfill. That’s 93.5%.

“I think the days of just literally bulldozing those projects over, just about anywhere, are gone. People will have to be thoughtful about where they are putting materials and separating materials,” said Michele Crane, Boulder’s city architect for facilities, design and construction.

“It absolutely can be done.”

Breaking it down

Boulder’s sustainable deconstruction requirements went into effect as part of the 2020 City of Boulder Energy Conservation Code, which set building regulations supporting the city’s climate goals, including 80% greenhouse gas reduction by 2050 and net-zero energy consumption by all buildings by 2031.

The requirement they set was 75% diversion from the landfill for projects with substantial structural alteration in over half the total building area. The deconstructor must submit a plan for that diversion with their permit application.

The new local laws have two main purposes, said Paul Goodrum, professor and head of the Construction Management Department at Colorado State University in Fort Collins. The first is to reduce the volume of materials going into landfills, after years of recycling rules with similar aims for smaller consumer items. Building materials come at such large volumes, any serious effort at reduction can keep millions of tons of debris out of landfills.

The second aim of the new laws is to reduce an area’s overall carbon emissions by reusing materials rather than making them from scratch, or even melting them down, which creates less carbon than initial manufacturing but still has a footprint. Cutting and reusing a steel beam saves a tremendous amount of energy, Goodrum said.

“It is something that we’re going to probably see increasing, especially in Colorado,” he said.

Since the 2020 ordinance, there have been about three private deconstruction projects a year, said Emily Freeman, Boulder’s policy adviser on a circular economy. Though the contractors are meeting the required diversion rate, she’s not sure their methods are maximizing the reuse value of the deconstructed materials.

For example, projects can still avoid the landfill by demolishing steel, then sending it to be melted down and remade into beams. But that involves much more embodied carbon than preserving the original beam and putting it in a new project.

“You drive by it and it’s hard to tell, are they actually doing it the way we would hope,” Freeman said.

Across all completed and reported deconstruction projects in Boulder since the 2020 requirements, diversion rates were slightly under 75%. The hospital project alone boosted the overall rate to 86.81%.

With this project, the city hoped to achieve not just the numbers but the spirit of deconstruction. Now armed with firsthand experience, Freeman has convened a deconstruction working group, and they’re interested in creating requirements around the integrity of the diverted materials.

Boulder Community Health sold the Balsam property to the city in 2015, as the community hospital consolidated more of its care at the Foothills campus.

They wanted to keep and repurpose the existing buildings as much as possible.

“The greenest building that exists is one that is still standing,” Freeman said.

Three of the four buildings in their purchase stayed up, to be reused as city offices.

But it was difficult to imagine a different use for the space purpose-built as a hospital, especially when the community wanted to bring in housing. The hospital superblock had disconnected neighborhood streets, and stole room for the kind of greenery and open space communities want.

“By the time you try to reuse that, you’ve actually taken most of it down anyway,” Crane said.

When a building is demolished, materials are usually crushed together and can’t be separated, which limits what products they can be recycled into. Deconstruction, on the other hand, aims to preserve what’s been built as much as possible.

Compared to the drama of a wrecking ball, it looks a little anticlimactic. Anna Perks, whose company specializes in deconstructing houses, calls it “surgical.” Her team of five takes everything apart with handheld tools, in reverse order from how it was first built – like pressing rewind.

She hasn’t worked on a commercial building like the hospital, but the idea is the same. The heavier exterior pieces just require heavier machinery. Take a steel beam, for instance: Workers cut the ends off by hand, then use a crane to transport each one from inside the building to the weighing machine, then to a neat pile of beams on the far side of the site.

That care requires extra time and hands on board, which means higher costs. Ameresco, the contractor for the hospital project, estimated the price tag at $20 million, 20% higher than the estimated cost of conventional demolition.

But that doesn’t yet account for the money and time savings from reusing materials in other projects.

“Many people don’t realize that these structural steel beams, they’re not just sitting on the Home Depot lot. They aren’t just kept in stock,” Goodrum said. “You have to see what the manufacturer’s schedule is.”

The city will put out a full report of the project costs, Crane said, incorporating savings from overestimating how difficult it would be to take apart the steel and social factors such as embodied carbon. The EPA and state government assign social costs of carbon at up to $190 a ton when assessing many new environmental rules.

Goodrum said he and his construction management colleagues will be very curious to see that final tally.

“You’ve got a complex economic model there,” he said.

Finding a new home

By weight, most of the diverted materials have already been put to use again. Aggregates including asphalt, brick and concrete made up over 90% of the diverted materials, which were crushed and used to fill in the hole in the ground where the hospital’s basement used to sit.

The next largest category of diverted materials, at about 4%, was metal: 3% recycled, 1% reusable steel beams. Some of these are in the new fire station building, but most are still sitting on-site, unused.

The city hopes to use some of them in the new housing on-site, over 200 affordable units to be constructed by Boulder Housing Partners in the next five years. But in the meantime, it’s kind of an open air Home Depot for builders. Anyone can express their interest to the city and take it for free.

“If there’s really anybody who wants this steel and can use it, they are welcome to it,” Freeman said.

They’ve labeled each beam and recorded its specifications, in case anyone comes looking. And because the new housing won’t be built out for a while, they can store the steel on-site until then at no cost.

For items inside the hospital, like doors and cabinets, the city contacted auction houses and thrift stores to take and sell them independently.

Bud’s Warehouse in Aurora takes materials from building sites and resells them at a discount to DIY enthusiasts on a budget. CEO James Reiner estimates receiving and reselling $50,000 worth of cabinets, sinks and commercial windows from the deconstruction project. In exchange, the city gets the donation tax break.

Though he hasn’t kept track, Reiner believes all the materials they received in 2020 have been sold. The warehouse turns around 75% of its inventory every year, and demand continues to exceed supply, he said.

“Especially with inflation right now, there are a lot of people looking to save money on home remodeling projects,” he said. “We’re definitely selling quicker than we can find.”

Since Bud’s serves the Denver metro area at large, they haven’t seen a big impact from the Boulder ordinance. But construction companies have shown more interest in Bud’s in recent years to avoid the cost of trash removal, Reiner said.

At the same time, with the recent influx of construction and remodels in Colorado, contractors may prioritize finishing projects quickly, making demolition the obvious choice.

It’s all about the cost comparison, Reiner said.

The other 6.5%

So why not 100% diversion?

Turns out, no one in Colorado will take some of the orphaned materials – yet.

Almost all of the interior material that ended up in the landfill was drywall. “Once you put drywall up, you tend to have tape on it, adhesives, paint, nails, you name it,” said Laurie Johnson, founder and director of the nonprofit Circular Colorado. “You can’t create one consistent solution, because your feedstock’s not consistent.”

It is possible, though, to use the gypsum that makes up most of drywall. In 2020, Johnson created a building block product, akin to a cinder block, by binding gypsum with plastic. The company she worked for at the time is not moving forward using that product, though she said she doesn’t know why.

Circular Colorado is funding similar projects now, focusing on possible binders that are also waste products in the construction industry, so that the resources coming out of that industry are the ones feeding back into it.

They’re also looking to bring in companies that recycle construction waste materials but don’t have locations in Colorado. “It has to be local for construction and demolition because all the materials are super heavy,” Johnson said.

In July, they contracted with ByFusion, which creates building blocks out of recycled plastics, to set up shop in-state. They’re also in talks with companies that process shingles, which Colorado does not consider a recyclable material, declaring in 2015 that “end-use markets for recycled asphalt shingles are currently extremely limited,” and would continue to be limited “for the indefinite future.” Johnson hopes there will be options for diverting materials like drywall and shingles in Colorado in the next two or three years.

Boulder’s search for customers for the reusable items is common in the early stages of developing recycling markets, Goodrum said. Recycling is often a push and pull between regulators and commodity markets: governments can mandate recycling of a concrete block or a plastic food clamshell with a “2” on it, but if no industry is remaking those items into something salable, the process stalls.

The city brought Johnson onto the deconstruction project to track and profile the different materials, knowing some of them would have to go to the landfill, she said.

“You can take the drywall off and take out the clean lumber on the inside. You can take out the wires and extract the metal,” she said. “So you still want to do deconstruction, even if there’s not markets for everything.”

What else is out there

“We don’t believe that this has been done, really, anywhere else in the U.S.,” Freeman said.

Palo Alto, California is the only other U.S. city that requires deconstruction of commercial buildings. The city did a pilot project with a 2,580-square-foot office building before adopting the ordinance, but nothing since, said Palo Alto environmental program manager Maybo AuYeung.

Waste diversion requirements for commercial construction and demolition aren’t widespread either. Other than Boulder, they’re only found in four local governments in Colorado: Denver, Fort Collins, Lakewood and Pitkin County. But unlike Boulder’s, these programs all require diversion of specific materials, like asphalt, concrete, metal and wood. None of them require deconstruction.

“I think it’d be great to have everything deconstructed,” Lakewood sustainability manager Jonathan Wachtel said. But they haven’t yet considered requiring it, for familiar reasons: lack of markets, higher costs and project oversight. The city’s current ordinance is more of a starting point based on what materials currently have markets in Colorado.

Without experience on the ground, Wachtel said he couldn’t speak to whether it’s harder to keep materials separated in demolition or deconstruction. Lakewood’s current administration system makes it difficult for contractors to report their diversion results, so the city is adding standards to their ordinance this year to improve that tracking. They will also implement a project deposit of $1 per square foot, to be refunded if the contractor meets recycling requirements.

“We really have to create a system that makes it as easy as possible, so the builder can see the standards, and we can help them to organize and to reduce waste,” Wachtel said.

Pitkin County has both a materials-specific diversion requirement and an overall diversion requirement, though at 35% it is much lower than Boulder’s. The county reported an 87.05% diversion rate from the past 12 months, but the figure is not comparable to Boulder’s because it includes soil, rock and dirt, which are easy to reuse and recycle, climate action analyst Michael Port said. And deconstruction requirements are better from a diversion standpoint, he said.

Other cities are considering deconstruction for the first time, looking to Boulder’s hospital as their example. Broomfield city manager Jennifer Hoffman said she will examine the pros and cons of Boulder’s project in determining the fate of the 180,000-square-foot 1stBank Center, though they haven’t yet decided what development will look like after the arena goes dark Nov. 30.

“Our goal as a community is to increase our diversion rate, to keep more materials out of the landfill, to salvage materials that are valuable. The question you’re asking me is, is deconstruction the right way to do that?” Lakewood’s Wachtel said. “It’s certainly one potential way to do it, and I think we’ll find out as we go through this journey.”

Many citizens have learned over time to expect and participate in reuse on a small scale, sustainability experts note. An aluminum can comes to look like a valued raw material rather than trash.

Breaking the mindset of scale is a challenge for deconstruction advocates.

“People look at old steel or panels, and don’t see the beauty in them,” Boulder’s Freeman said, standing amid the field of red steel beams rescued from the hospital.

“Those resources are lost,” she said. “That’s the tragedy of demolition.”