April 2008 The 4,800 sq. ft. military administration building took 12 blocks and less than 80 days to be site-finished.

Decommissioned cargo containers recycled into building blocks

Rather than see decommissioned steel cargo containers sent to steel mills as feedstock, St. Louis, Missouri-based SG Blocks LLC is converting these 8,000-pound containers in framing systems for commercial, industrial, military and residential structures.

Among its projects are a command office building at Fort Bragg, North Carolina and facilities that are being constructed at a port in Jacksonville, Florida.

“Shipping containers are usually in service for 6 to 10 years,” says David Cross, SG Blocks, business development director. “Our purpose is to take those containers and, depending upon the requirements of the project, Value-Cycle™ them into a superior building product, which requires a minimum amount of energy expenditure.”

Containers, says Bruce Russell, SG Blocks’ managing director, make for a sturdy building material because they were designed to be waterproof and withstand the effects of salt and waves at conception. Moreover, because the cargo has to be delivered intact, containers are well-maintained while in service.

“The framing from containers is very durable and it stands up well to hurricanes and earthquakes,” says Russell. “They are extremely strong and have all the necessary floor systems and structural elements because they were built to hold 60,000 pounds of cargo – to resist 15 long tons (2,240 pounds per long ton) traversely and 7.5 long tons longitudinally.

“The steel itself is Cor-Ten or Weathering Steel – a better grade of steel to start with,” he adds. “When the buildings are done right, we are able to give the container another 50 years of life. This is a very efficient method of building that is safe because of the inherent strength of the steel. The leftover materials can be recycled into new steel.

At a house and home show, a two-story home was assembled in just four hours.

“We are doing a lot of work in hurricane areas, particularly in areas along the Gulf Coast,” he adds. “We want this building to not only be standing, but to avoid mold problems – the insulation and drywall should not get wet.”

One SG Block is the equivalent of one container and for the Fort Bragg project, 12 blocks were used. Prior to shipment, each block undergoes rust proofing and is subject to other protective measures.

Worldwide, Cross estimates that there 22 million TEU (twenty foot Equivalent Units, the measure of containers) in service, with nearly 1 million new containers being brought into service annually and about 700,000 being retired.

Because container traffic is thoroughly monitored, retired containers can be easily shipped to facilities for SG Blocks to begin the ValueCycling process, along with a report on the maintenance history of each container.

“Our primary source for containers is ConGlobal Industries, the largest depot operator in the country,” says Russell. “They have partnered with us and are very supportive because it keeps their inventories cleaner and more efficient.

“We prefer to use the 6, 7, 8 and 10-year-old containers,” he adds. “This is still a new technology and we are in the middle of doing various tests and assemblies to make sure that all building code issues are resolved. The construction industry is extremely conservative and it moves slowly, so it is our job to satisfy them.

“We have several engineers and they are working to make this a routine product so architects and developers fully understand what an SG Block’s benefits are and how they fit with building codes,” he adds.

“We are in discussions with numerous military bases and municipalities,” says Cross. “This also offers the advantage of having a minimal footprint in terms of impact on the environment. They can be assembled on-site and disassembled to be moved to a new location.”

“At Fort Bragg, it was estimated that the complex would take 132 days to complete traditionally,” he adds. “With our system, just installing the modified blocks, no cladding or drywall, reduced the construction time by 30 percent.”

SG Blocks has created a national distribution system that is based on ConGlobal, which has facilities on all three coastlines and in the key transportation centers of Memphis, Tennessee and Chicago.

Using SG Blocks translates into points towards LEED (Leadership in Energy and Environment Design) accreditation based on the use of recycled construction materials and reducing the travel distance for the materials.

“One of our partners is an architectural firm and they have done a pretty strong analysis for LEED construction,” says Cross. “We are making our product very friendly for use by the construction industry and the various sub-trades.”

Furthermore, the framing system can be used in all climates, be it extreme cold or heat. Russell says that the firm is considering possibility of using the steel for the construction of bridges, pedestrian walkways and similar infrastructure.

“It’s just a matter of the engineering and the applications,” he says, noting that creating sections for buildings with SG Blocks is similar to pre-fabricated concrete construction. “One of the biggest problems in the recycling industry is the introduction of new materials and uses for them. We are trying to make our product understood by the mainstream of the architectural and building communities.”