BURLINGTON, Vt. – Historic covered bridges could one day contain plastic, but the idea drew mixed reviews at a conference attended by more than 200 engineers and historic preservationists last week.

Using man-made materials to reinforce covered bridges was the topic of a seminar during the conference held at the University of Vermont.

“The bottom line has to do with maintaining wooden covered bridges as a viable part of the transportation system, and not just as museum pieces,” said Thomas Visser, a professor with UVM’s historic preservation program and a coordinator of the conference.

The conference was the first national event focusing on preservation of covered bridges, Visser said. There are fewer than 1,000 covered bridges left in the United States; of those, about 75 are in Vermont.

“We must save these bridges,” said Samer Petro of the Institute for the History of Technology and Industrial Archaeology at West Virginia University. He gave a presentation Thursday on “Preserving Historic Covered Bridges Using Glass Fiber Reinforced Polymers.”

Plastic is relatively affordable compared to wood or steel, Petro said, and unlike steel resists condensation that can cause wood decay. He said polymers can be “veiled” to match the natural wood grain.

Some engineers who attended Petro’s talk were not sure they would use plastic made to look like wood.

Ron Mattox, an engineer with DLZ Ohio in Columbus, said he would prefer to have an obviously modern structural repair than one that tries to “fool” viewers.

Justin Spivey, a structural engineer with Robert Silman Associates in New York City, agrees. “It’s plastic, it’s made in a factory, it’s not a natural material,” Spivey said. “It’s false.”

Visser said there is “a certain amount of professional tension” between those who favor modern and traditional techniques.