An edited version of this appears on the USGBC National website.
Roughly 23% of national waste generation comes from construction and demolition.
As a general contractor, there are a limited number of LEED credits that we truly have control over versus those that are under the purview of the project owner or architect. When LEED v4 was introduced, efforts were centered around materials procurement for the new Building Product Disclosure and Optimization (BPDO) credits. Construction Waste Management had always been straightforward for teams to achieve. Excluding alternative daily cover (ADC) from points that could be achieved added some complications, but was doable. ADC means cover material other than earthen material placed on the surface of the active face of a municipal solid waste landfill at the end of each operating day to control vectors, fires, odors, blowing litter, and scavenging (via CalRecycle). Source separation is critical for tipping the project overall diversion percentage over 75%.
Through COVID-19, we began noticing concerning reports from the waste facilities with whom we work. Diversion percentages were dropping dramatically, some by 30%. Getting those 2 LEED points for 75% diversion and four waste streams were no longer a given. Projects were moving one point to the “maybe” column as there was uncertainty about reaching that 75% target even if there were enough waste streams. Some teams even looked into switching facilities mid-project. What we learned was that construction and demolition recycling centers were struggling with staffing just like other industries due to maintaining social distancing and workforce reduction. 2+ years later, diversion rates do not appear to have recovered.
In California, the CALGreen building code mandates projects achieve at least 65% diversion (though that doesn’t specify ADC). LEED v4.1 briefly introduced a pathway for including third-party certified facilities (now back to a pilot credit). Certification provides accountability which helps increase confidence in the data we were receiving. Facility process transparency is important, but we’re seeing that very few facilities can achieve 65% diversion without ADC – in California there is only one. It becomes difficult to compare and trust reports from non-verified facilities. To add another layer of complication, many cities have franchise agreements, and some project teams have no choice to which facility their waste is taken. Therefore, project teams cannot rely on recycling facilities to meet their LEED or CALGreen diversion goals alone. They must get creative and consider how to reduce waste in other ways besides just commingled recycling.
So the priority then lies in site source separation. Everyone should be recycling 100% of their metals and concrete! For commercial interiors projects though, there are fewer opportunities. And then we run into a new set of issues. Does the facility/region even have the ability to recycle certain materials? Is there a market for drywall? Even wood or cardboard can sometimes be out of reach. When clients have higher diversion requirements, teams can get creative, and address logistical challenges. Sometimes the material must be taken to another location by a trade partner instead of using a hauler. But this isn’t feasible for most projects.
Well then, the big question is: how can we reduce the amount of waste we’re generating in the first place? LEED v4.1 has an option for total waste reduction of 10lbs/SF or 15lbs/SF. However it’s hard to know if you will reach this goal until construction is well underway. These waste struggles directly tie into conversations the industry is having about embodied carbon and the circular economy. If we pull back and take a systems perspective, we can begin to look at the interaction between construction waste, and credits like “Whole Building Life Cycle Analysis (LCA)” or pilot credit “Procurement of Low Carbon Construction Materials”.
Building owners need to start prioritizing retrofitting existing buildings. This reduces embodied carbon impacts by reducing demand for new products, minimizing waste generation, and demonstrates improved LCA reductions. The AEC community is having important conversations about the circular economy and how to create demand for salvaged materials so they don’t need to go through a recycle center, “designing for deconstruction”. Some strategies include highly flexible floor plans, prefabrication, prioritizing mechanical fastening over adhesives, and allocating schedule and budget for “soft demo” or careful deconstruction in order to recover more materials.
It’s important to remember that the original goal of the Construction and Waste Management credit was to reduce overall waste. Letting this goal inform project choices, and design will also reduce embodied carbon that will reduce global GHG emissions, to create a more circular approach to someday work toward a built environment that operates more like the natural world, where nothing is wasted.
Takeaways:
- Start the waste conversation with the project team prior to beginning construction. Identify key materials for source separation.
- Research facilities in your area, advocate for third-party facility certification.
- Prioritize retrofits, incorporate salvaged materials, promote circular economy
