Construction generates a lot of waste materials. Whether new building construction or tenant improvements, usable building materials are often discarded to accommodate new tastes, manage tight construction schedules, or simply due to lack of recycling and diversion programs. Green building programs like Leadership in Energy and Environmental Design (LEED) have helped focus more attention on waste minimization at the construction site, and many builders go the extra mile regardless of whether projects are formally evaluated. Understanding waste composition and diversion opportunities can help projects meet their sustainability goals.

Waste Stream Characterization

According to a 2004 waste characterization study conducted by the California Integrated Waste Management Board (CIWMB), construction and demolition (C&D) waste accounted for approximately 21.7 percent of the total waste stream. Only organic waste, at 30.2 percent, was higher. A second CIWMB study, conducted in 2005, examined the composition of California’s C&D waste stream itself. A total of 622 loads of C&D waste across four metropolitan areas were visually characterized according to 86 material types. Demolition materials comprised the largest single portion of the waste stream at 21 percent. Programs or services to help recycle or divert some of this demolition material can help lessen the burden on rapidly filling landfills.

Managing Construction Waste

It’s become commonplace for reputable builders to develop waste minimization plans for each job. “Regardless of whether the job is pursuing LEED certification or not, minimizing waste is a responsible building practice,” said Josh Bronitsky, project engineer with DPR Construction in San Francisco. “We see it the same as safety practices or good estimating, and incorporate it in all of our jobs.”

Recycling and diverting C&D waste helps keep usable materials from going to a landfill but can also reduce tipping fees. On one DPR Construction job in San Francisco, the 45,000-square-foot tenant improvement project required twenty-three 30-yard dumpsters to handle demolition waste. Fortunately, 20 of those dumpsters contained source-separated materials like carpet, drywall, metal studs and more that were targeted for recycling.

In addition to simply recycling the C&D waste, most metropolitan areas have companies that salvage building materials for reuse rather than recycling. Some companies focus on electrical and mechanical equipment while others salvage windows and doors. It’s important to have one of these companies visit the site early to identify materials that are salvageable. For insurance or labor issues, or to better coordinate workflow, builders often choose to use their own workers to remove and palletize materials for pick up.

Salvaging building materials can help project teams gain LEED points across several different categories. The most obvious is waste minimization. By recycling and/or salvaging at least 50 percent of non-hazardous construction and demolition debris, projects can gain one point in Material and Resources Credit 2.1. An additional point is awarded if diversion exceeds 75 percent. Calculations can be done by weight or volume, but must be consistent throughout.

Enlarge this picture Source: California Integrated Waste Management Board, Detailed Characterization of Construction and Demolition Waste, June 2006.

On that downtown San Francisco project, DPR Construction’s goal was a staggering 95 percent recycling and diversion rate. The project team brought in Industrial Asset Recyclers, a company that specializes in commercial equipment salvaging, to evaluate areas for potential diversion. The construction team removed, weighed and palletized 160 light fixtures that couldn’t be reused with the new design.

“From our experience, light fixtures are usually one of the hardest to reuse or recycle,” said Clark Chatterley, superintendent at DPR. “Depending on the fixture’s age, they can be reused, but you may spend the time and effort installing new ballasts, or continually moving them around the site to prevent damage. Finding a company to take the fixtures helped DPR achieve its diversion rates on the job and has helped move us along toward LEED Platinum.”

Salvaged equipment can also help projects gain LEED credits or reduce equipment costs by sourcing used equipment. From mechanical equipment to ceiling tiles to interior doors, salvaged building materials can save owners money. On a 47,000-square-foot tenant improvement in San Rafael, Calif., DPR was able to install more than 200 used light fixtures.

“The goal was to achieve LEED Gold for the project and installing used light fixtures, along with doors, helped us achieve the material reuse credit,” said Ross Solis, superintendent for DPR. “The fixtures were in excellent shape and only a third of the cost of new ones, so it just made sense.”

Regardless of whether a project team is trying to minimize C&D waste or save money by sourcing used equipment, waste diversion and salvaging helps promote greener buildings.