Boulder chooses deconstruction over demolition to divert waste from landfill
Boulder officials, with the help of contractors, are out to prove that when a commercial building meets its end of life, many parts of that structure don’t necessarily have to go to the landfill graveyard.
They instead can be reincarnated or get a new life or new home through reuse.
In recent months, contractors for the City of Boulder have been carefully dismantling the exterior portions of the former Boulder Community Health Hospital along Broadway in North Boulder.
Back in 2015, Boulder bought the entire 8.8 acre site of the former hospital and other related structures, now known as the Alpine-Balsam site, to make way for redevelopment.
That includes affordable housing and a municipal hub for city and other governmental services.
So why is Boulder carefully dismantling the former hospital instead of doing typical swift demolition?
Well, one reason is that Boulder is following its own deconstruction ordinance, passed in July of 2020.
Emily Freeman, who oversees the city’s requirements explains it covers both residential and commercial properties and, “requires that 75% or more by weight of that building be recycled, reused, or go for organics management as well.”
But a distinction for the Alpine-Balsam site is that Boulder officials and the city’s contractors are attempting to go beyond the requirements of the ordinance by prioritizing reuse.
“What this project is all about is reusing, and that’s the key word, is reuse versus recycle,” says Mike White, who works for the city’s general contractor Ameresco.
“All of the mortar and the brick and the concrete gets crushed to a construction grade level and fills the hole for future development of this site. So it will get compacted and reused.”
Another purpose or added benefit of deconstruction and reuse is that it does not entirely waste the past carbon energy that went into creating a building in the first place.
This means preserving the building’s embodied energy or embodied carbon.
Embodied carbon is generally defined as all of the CO2 that gets emitted while making a building and its parts.
As Boulder began the process, city officials had to decide what structures would get preserved, rehabbed, or deconstructed.
Freeman, who is part of the city’s circular economy team, also wears the hat as policy advisor to the climate initiatives department.
“Reuse is what we want to see, and that preserves the embodied energy and the carbon within our built environment in the city," she said.
"And we only want to see deconstruction of that entire structure when that building has reached its end useful life.”
When it came to deciding the fate of the former hospital, city officials determined it would be a challenge to keep the structure entirely intact for new uses as it had 20 plus additions over the years.
But before they could give the green light for the hospital’s deconstruction, they first had to figure out another carbon challenge – the high amount of energy the empty building was using.
Michele Crane, chief architect with the city’s facilities department and Boulder’s project manager for the Alpine-Balsam site, explains that due to the sheer size of the building, even in a vacant state, the energy bill was nearly a million dollars a year.
“So we quickly wanted to minimize that and understand how we could turn mechanical, electrical, and plumbing systems back to minimize that cost while at the same time not freezing pipes,” said Crane.
“You can’t just turn a building off.”
After decommissioning the hospital’s mechanical systems, the city and the contractors then started the deconstruction of the hospital’s interior.
As part of that process, they identified elements that could be directly reused for other projects.
One of those was the hospital’s ceiling tiles which will be reused in a different building.
The city then worked with local companies to recycle materials such as lighting fixtures, carpet squares, glass, cabinetry, doors, and plumbing fixtures.
Mike White of Ameresco says deconstruction of the interior took a year and half further complicated by pandemic delays.
“It’s a slow process of doing room by room, by room. Ceiling tiles, right, floors, squares. So, I segregated all the materials. As a matter of fact, the one material I haven’t mentioned yet is what’s called e-waste," he said.
"So it’s a lot of computer parts, computer boards. A lot of patient lights are run by little computer boards these days. So we separated all of that and uh, went through a proper local e-waste recycler.”
Although recycling is important, Boulder’s Emily Freeman says that direct reuse is the ultimate goal.
The city put some of the salvaged mechanical equipment up for auction instead of selling it as scrap metal.
However there was one prominent material they were not able to divert and it held a lot of weight.
Freeman says something like 97% of the building’s interior by weight was drywall.
"And so you’d think of all the hallways in the offices. And so while we did a great job at reuse and recycling of interior things, that was still only 3% of the weight of the interior of the building,” said Freeman.
But the upside of the drywall obstacle was that it got Boulder officials thinking about new best practices, especially when it comes to designing buildings for future deconstruction.
Freeman says it sparked discussions about how many times the city does a renovation and whether other materials could be useful in construction to facilitate deconstruction.
"And can we look at other types of wall systems that might be more modular, and would allow us to reuse those same walls instead of just continually sending something to the landfill?”
There has been one big success story from this project and that is the reuse of steel.
Girders, I-beams, and other support elements will be used in future city projects, such as Boulder’s new Fire Station 3.
Alexis Feitel, a structural engineer with Golden-based KL&A, that has been working with the city, says there’s been industry support for the reuse of finished material such as doors and windows, but as far as structural material, it’s pretty brand new to North America.
“This has been done in Europe a handful of times, but this is a pretty new process to the industry,” she noted.
“Oftentimes buildings just get demolished and steel especially will get recycled, so that is a good thing. It can kind of infinitely be recycled as a material, but it’s very rare to find projects that actually deconstruct and then directly reuse pieces.”
As Boulder wraps up the deconstruction process, city officials and the city’s contractors will generate informational reports and landfill diversion tallies.
They estimate the diversion report will be ready this summer.
In the meantime as the waste diversion junkies await the results, Mike White of Ameresco expresses this optimism for the hospital’s exterior materials.
“I think we’re gonna hit 90% landfill diversion. As you look at all of the concrete and all of the steel that we’ve pulled out and separated, it’s gonna be good,” said White.
This story was shared via Rocky Mountain Community Radio, a network of public media stations in Colorado, Wyoming, Utah and New Mexico including Aspen Public Radio.