Just when you thought soybeans were grown mainly for soy burgers and hot dogs, products made from those lively legumes seem to be everywhere in the home and beyond: behold soy-based insulation -- and soy carpet backing, soy ink, soy diesel fuel, soy animal feed and so on. Or rather, "and soy on." For example, Americans used 450 million gallons of soy-based diesel fuel in 2007, compared with 25 million gallons in 2002 [source: United Soybean Board].
And so the question arises: why soy for building materials, fuel and food? Perhaps most importantly, as the United Soybean Board points out, soybean farming equals American jobs. Ever driven through or flown over Iowa? It's either soy or corn as far as the eye can see, and someone needs to work those fields.
Soy is a renewable and sustainable material. Consider this three-step process: plant, harvest, plant again. That's a far cry from the drilling of fossil fuels, which were eons in the making and are nonrenewable. Growing soy involves no drilling, no spilling and no sending American dollars overseas.
But you may wonder; with soy used for building materials like house insulation, won't insects and rodents stop by for a meal? Not to worry -- by the time soy is transformed into an oil for use in soy-based building products, all food value is gone. In fact, these products tend to be naturally pest-resistant without added chemicals, making soy-based products attractive to those with chemical sensitivities or those who simply want cleaner indoor air.
One of the increasingly popular uses for soy is soy-based insulation. It may not be on your walls yet, but it could be in the near future. Find out how on the next page.
To understand how soy-based insulation fits into the grand scheme of your insulation choices, it helps to consider the full array of insulation materials used today:
Fiberglass: This insulation is rolled out in batts and placed between studs in a wall before the drywall or sheetrock gets installed. It's economical and can be installed by a do-it-yourselfer, but if the batts aren't sized properly and gaps are left, the cold or heat from the exterior air you don't want getting into your house will get in anyway. Plus, fiberglass fibers are itchy when they touch your skin during insulation.
Cellulose: This is wood-based, fluffy material treated with borate to repel pests. It's blown into wall cavities and attics.
Rigid foam: These are panels of stiff foam that are placed between the studs. Most foam insulation products are made from petroleum-based oils.
Blown-in foam: This is a two-part product that's blown into wall cavities (usually by certified installers) as a liquid that expands up to 100 times and solidifies into a rigid foam (think Styrofoam), sealing every nook and cranny. This is where the soybean oil-based material comes into play. Typical foam comes from petroleum-based materials and is blown into place using urea formaldehyde, which has been classified as a carcinogen and is being phased out. Soy-based foam, on the other hand, uses water as a blowing agent.
You'll find two types of soy-based foam insulation: open cell and closed cell. The former has a lower R-value (a rating of how well materials resist the flow of temperature from outside to inside a building) and is less expensive, while the latter has a higher R-value, is more expensive and acts as a vapor barrier as well as an air barrier.
Soy-based foam insulation is a darling of the green-building movement because it not only helps save energy, a base requirement for green building, but it also comes from a renewable source and is less toxic for humans. And the price will likely go down as mass production goes up.
If the United Soybean Board and the American Soybean Association have their way, soy-based products will become more ubiquitous over time, here and overseas. According to the board's Web site, "Success for soybean farmers in today's market takes more than just a good harvest. Increasing demand for soybeans is an essential part of the equation" [source: United Soybean Board].
So where will these beans show up next in our homes? Soy-based cabinets? Soy-based crown molding? Soy-based sheetrock? You can be sure all possible uses are being considered.
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More Great Links
- BioBased. http://www.biobased.net/
- PATH concept home. http://www.pathnet.org/sp.asp?id=11175
- Phone interview with building science expert Bill Robinson.
- United Soybean Board. http://www.unitedsoybean.org