Although large commercial operations may opt for PVC fabric structures for their look and endurance, the predominant material used by the agriculture industry is polyethylene, which is considerably less expensive and offers greater light transmission.
“It’s an industry standard. It’s been around for well over 20 years,” says Joe Teixeira, truss arch specialist for ClearSpan Fabric Structures. “It’s been proven in the field in both frame structures and in hay tarps and for other commodities. It’s very flexible. It’s very tear resistant, high strength and provides an extreme amount of UV resistance and longevity. Light transmission is on the order of 20 percent, so you get natural light in the structure.”
For greenhouses, ClearSpan uses polyethylene film. “It’s almost glass clear,” Teixeira says, noting its light transmission of 92 percent or higher.
Gidco Ag Design & Consulting primarily uses black, UV-stabilized polypropylene and polyethylene for crop shades and clear woven insect screen in different types of meshes.
“Some are very dense,” says owner Gideon Cohn. “We also use bird netting with larger holes over tree crops, berries and fish ponds.
“We find out over time what crop is sensitive or would be best with a selective light,” he continues. “We can do selective colors to manipulate the crop, for example to produce earlier. It’s not a genetic change. We also use different products to change or stabilize temperatures. You have to experiment all the time.”
Jason Owen, president of Accu-Steel Fabric-Covered Building Solutions, says polyethylene has improved over the years.
“Film technology in the polyethylene marketplace has really had a lot of UV stability, which translates into savings for our customers,” he says. “Companies are able to add more coatings at lower temperatures that preserve the UV integrity of the product.”
Jeremy Calhoun, president of Calhoun Super Structures, agrees. “Polyethylene is getting better each and every year, offering more life span, more consistent coatings, a better welding temperature and better fit and finish.”
As for frames in the agricultural market, they are typically hot-dipped, galvanized steel.
“There’s no better value in a corrosive environment,” Owen says.