Industry Market Trends

Straw Gets High-Tech Touch as a Green Building Material

Jun 11, 2012

With the first pig's experience in Three Little Pigs excepted, the world early on found straw to be a useful building material. Of course, as humanity became smarter and things got more complex, the world moved on to sturdier materials. But proving again that everything old is new, a company named Stramit USA is bringing back straw as a sustainable building material, but this time with some high-tech upgrades.

At its 88,0000-square-foot manufacturing facility in Fort Worth, Texas, Stramit USA is filling the need for traditional light-gauge framing materials with a proprietary and sustainable compressed agricultural fiber (CAF) product called Stramit CAFboard. The "agricultural fiber" is straw, of course.

Straw is a largely worthless and voluminous waste by-product of the wheat farming industry. Through Stramit CAFboard, Stramit USA puts it to use, replacing traditional materials like fiberglass insulation, gypsum board, medium-density fiberboard, particle board and sound-proofing panels in a wide range of commercial and residential structures. It's also nearly carbon-neutral and about as green as a modern building material can get, being nontoxic and mold- and pest-resistant. And, no doubt, wheat farmers will be delighted to find a market for the tons of straw they generate and currently leave to compost.

"The concept of taking a valueless by-product from one process -- in this case, the wheat harvest -- and creating something of value is what we refer to as 'upcycling,'" says Phil Morley, Stramit USA's director of design who's also a LEED Accredited Professional and a member of the American Institute of Architects. "Stramit's process produces a carbon-neutral product that is strong and durable. These materials are good for the environment from start to finish and can help those seeking LEED credits for their building projects."

Significant LEED credits, as it turns out. Specifically, the CAFboard building system can help contribute up to a total of 14 LEED points toward a certification under USGBC 3.0 of the U.S. Green Building Council, according to Stramit USA, under the categories of "Innovation & Design," "Indoor Environmental Quality," "Materials & Resources" and "Energy & Atmosphere." (Find the specifics here.)

So how is CAFboard made? With a specialized machine nearly as long as a football field, according to Stramit USA. Ordinary straw bales are placed on the machine's conveyor and then broken apart, screened to remove debris and short strands and then dropped down a chute before being compressed, under extreme heat (at about 400 degrees) and pressure, into a rigid board using a reciprocating ram.

There are no adhesives needed, as under high heat and pressure, straw releases its own natural binder called lignin. The panels, which can be created into any form a builder might need, are then wrapped in heavy-duty organic paper and finished to project-specific lengths.

The end result is a completely organic product with no added formaldehyde or volatile organic compounds (VOCs). It can replace pretty much any traditional building material, as a much safer solution, according to its manufacturer.

"Many traditional construction materials available to builders and consumers contain unhealthy levels of formaldehyde and other toxins," says Tim Evans, Stramit USA's executive vice president of sales and marketing. These toxins often leach out and contribute to poor indoor air quality, particularly in tightly built buildings designed to be as energy efficient as possible.

CAFboard is also inherently near fireproof, according to Stramit USA. The heat and compression process basically squeeze out all of the oxygen in the straw, leaving nothing to feed a fire. When exposed to a flame, the material builds up a layer of charcoal on the outside, which slows the burning considerably, giving the product a very strong fire rating without the need for harmful chemical fire retardants.

Proving that not all pollution is of the chemical or elemental kind, the building material could also go a long way toward preventing noise pollution. CAFboard's sound-muffling properties are created by the internal wheat straw matrix; it's highly soundproof and therefore suitable for theaters, recording studios or any other place where sound reverberation can be a problem (e.g., the apartments of tenants who don't appreciate their neighbors' music choices or late-night hours).

Producer Hopes to

Duplicate UK Success

While the finished product may be new to the United States, it's not in Europe. Stramit USA, which purchased its machinery and licensed the technology from Stramit Technology Holdings, based in London, may be bringing CAFboard to North America, Central America and the Caribbean, but the product has been manufactured and used in the United Kingdom for more than 70 years. The Stramit technology was developed in Europe in the 1930s and has been used extensively in buildings across the continent and Great Britain. Many of those buildings are still in use today.

"Stramit and compressed agricultural fiber board have a long and proven history in the United Kingdom and throughout Europe," says Tim S. Kilpatrick, CEO of Stramit USA. "It's time to bring this product and a new level of environmental stewardship to North America, as well. It's simply the right thing to do, and we anticipate a broad and eager acceptance of the technology and its products," he adds.

The official launch of the Fort Worth-based manufacturing facility took place in early June, with an invitational event. The plant is located on 6.5 acres about 5 miles south of downtown. During the event, Stramit USA executives provided attendees with a demonstration of the manufacturing process. A number of people spoke at the launch, including Fort Worth Mayor Betsy Price; Todd Staples, Texas' agriculture commissioner; and Rhiannon Jacobsen, the USGBC's director of strategic accounts.

Still, the product isn't entirely unknown to North America. One of the finest examples of the technology within U.S. borders is at the Fort Worth Texas Post Office (8th Avenue Station). The government facility, which was Texas' first LEED Gold-certified building, was built in 1997 out of CAFboard. (The builders left a "window of truth" in the edifice to allow visitors to view the straw interior of the boards.)

Stramit USA presents the cost of the product as neutral to conventional construction materials, but Evans told Green & Clean that, in actuality, CAFboard often proves to be cheaper when operational cost are factored in. Stramit USA can also make the construction materials, panel systems and other related components in the new Fort Worth factory faster than convention materials, delivering them to job sites on an as-needed basis. When compared to conventional technologies, the company says its system can reduce the time to build shells to as little as 10 percent of traditional construction time.

"If a traditional construction project takes up to 10 weeks, you could expect the Stramit panelized system to take about one week," Evans claims.

Fast, light, cost-neutral and truly green -- Evans stressed that there's no greenwashing with CAFboard -- about the only one who won't be enthused about the product is the Big Bad Wolf.