The construction industry produces a huge amount of waste. In the US alone, about 40 percent of solid waste comes from construction and demolition (C&D).
To combat this, one US city is taking the unique approach of banning home demolitions, which it says will encourage the reuse of building materials and decrease waste send to landfills.
The Portland, Oregon, city council yesterday passed a law banning the demolition of homes build on or before 1916. The law requires old homes to instead be deconstructed, allowing builders to salvage and reuse lumber and other materials. The city expects the new deconstruction policy will divert 8 million pounds (4,000 tons) of materials for reuse annually.
The city council last winter adopted a resolution in support of the home demolition ban, and late last month reviewed the changes to the city code, KLCC reports. The council’s official vote happen yesterday. The new law will take effect Oct. 31 and the council may consider expanding the policy to cover more of its homes.
The mayor’s office told KLCC about 20 percent of Portland’s landfill waste comes from C&D material. In addition to reducing waste, deconstruction (instead of demolition) cuts air pollution and the release of toxics including lead and asbestos, which will help Portland meet its carbon reduction goals.
The demolition ban follows a report by the World Economic Forum and Boston Consulting Group that found reusing and recycling C&D material could provide big business and environmental benefits to the construction industry.
The construction industry is the largest consumer of raw materials globally and yet less than one-third of construction and demolition waste is recycled or reused, the report found.
Reusing discarded asphalt products as road-building materials and waste lumber as wooden flooring material costs less than producing new products. And considering constructed objects account for 25 percent to 40 percent of the world’s carbon emissions, recycling these discarded materials present a huge opportunity for the industry to reduce global emissions and make their businesses more environmentally sustainable.
“It is estimated that 54 percent of demolition waste in Europe is still landfilled and most recycling occurs in low-value applications,” World Economic Forum’s Dr. Michael Max Buehler told Environmental Leader in an earlier interview. “The potential for the industry to identify closed material loops and to adopt circular design principles is tremendous.”
While Portland is the first city in the US to ban home demolitions, other cities including Vancouver, Canada, have successfully reduced waste with similar policies, Lux Research analyst Jerrold Wang said.
“In 2014, Vancouver banned demolition of its old homes built before 1940,” Wang told Environmental Leader. “The result seems to be successful, and the city may consider expanding this demolition ban to the homes constructed before 2015 in the future.”
Deconstruction achieves better recycling rates than demolition — but it’s typically only applicable to single-family homes and duplexes because of the high amount labor and time required, Wang said.
“But interesting thing may happen in the future when prefabricated buildings are disassembled into components, and then further processed with deconstruction as well as waste sorting robotics,” he added. “We believe this new process needs short disassembling time onsite and moderate amount of labor work, while realizing high recycling efficiency. The keys are to 1) make building easier to disassemble, and 2) use automated process to replace manual work.”
Meanwhile, we’re keeping an eye on Portland’s C&D waste management progress — and wondering if other cities will follow suit.