Housing construction and demolition waste account for 40 percent of what’s going into landfills. Nathan Benjamin and Willow Lundgren want to shrink it to 30 percent by 2020.

PlanetReuse consults with architects, contractors, and building owners and sells technology to reuse centers to rescue materials during demolition and find homes for reclaimed materials in new projects.

“Perfectly usable materials are buried,” says Benjamin. “Our aim is for owners to think ‘used’ before ‘new,’ and to make reuse the obvious alternative to landfill.” —KK

via America’s Most Promising Social Entrepreneurs 2012 – For Profit, for Good – Businessweek.