"We take instruments of trade -- cargo containers -- and turn them into instruments of construction," David Cross, the company's business development director, told ABCNews.com.
Through a partnership with ConGlobal Industries, a leading retailer of shipping containers, SG Blocks has access to a network of 17 depots in North America that house used containers.
But sourcing containers close to their destination sites, the company can significantly cut down on energy costs.
At these depots, metal workers torch, weld and remove rust to transform the battered steel boxes into large building trusses, he said.
Depending on the container's condition, one container costs between $1,500 to $4,500 and needs about 100 hours of labor to prepare it for construction, Cross said.
In the last year, the company has converted about 100 containers for a handful of projects, including a two-story office building for the U.S. Army in Fort Bragg, N.C. Designed by the St. Louis, Mo.-based architecture firm the Lawrence Group, the building was made from 12 shipping containers converted by SG Blocks.
In the next two years, the company expects to convert 5,000 containers for 50 to 80 residential, commercial and mixed-use projects across North America.
"Builders and developers are looking for a leg up. Everyone is really wanting to be green," said Bruce Russell, managing director for SG Blocks.
Noting that the process of converting the containers into construction blocks consumes far less energy than the process of totally melting the whole container down, he said, "we have the greenest building structural system that there is."
Attracted by the company's sustainable approach to construction, developers, architects and builders have had an overwhelmingly positive response, Russell said.
Right now, the company is working on a 220-unit dormitory for Lubbock Christian University in Lubbock, Texas, and a senior housing development in Oceanside, Calif. SLS Partnership, Inc., a Lubbock, Texas-based architecture firm, designed the dormitory and the Lawrence Group designed the housing development.
Because the containers were designed to brave the elements at sea, they're perfect for hurricane- and tornado-prone parts of the country. They're also best suited for multiunit buildings.
"The higher we go, the more cost advantageous it is," said SG Blocks' Russell.
Fifteen containers can be installed with one crane in one day, which means that months can be shaved off construction time.
"This is far faster than conventional construction," said Dan Rosenthal, a principal with the Lawrence Group. "There are significant savings associated with that."
The larger the project, the more apparent the savings, he said. But, in general, an SG-based project is at least competitive with, if not 15 percent cheaper than a conventional project.
John K. McIlwain, a housing expert at the nonprofit Urban Land Institute who saw an SG Blocks-Lawrence Group home at a recent conference, said he was impressed by both the economic and the environmental benefits of the innovation.
"They strike me as a very practical solution to lowering the cost of construction," he said. "While costs of many materials are coming down, it's still going to go back again."
Given the state of the economy, finding ways to reduce housing costs is very important, he said.
"It's not the answer, but it's one of the ways we can provide attractive decent housing to people at a lower cost of production."