Rice husks used to be considered a waste product good for nothing but fire or landfills, but now enterprising companies are beginning to realize their potential as a sustainable building material. A group of students from the Riverside’s Bourns College of Engineering at University of California used waste rice husks to manufacture termite-resistant composite boards with help from a $75,000 grant from the Environmental Protection Agency (EPA) to develop and build affordable housing in the Philippines.
In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material or fuel. The students at Riverside’s Bourns College of Engineering used it to manufacture boards ideal for building relief shelters and affordable housing.
The Husk-to-Home team developed the project by environmental engineering student Colin Eckerle who has been working on it since 2014. However, the rice husk boards last longer. The students received a two-year grant by EPA which will pay for manufacturing equipment and space and allow the team to go into full-scale production of the boards.
In the design, the rice husks—a waste product of rice milling– replace commonly used woodchips. They are a great alternative to plywood, bamboo and coconut wood. Eckerle claims the board will cost about $7 for a 4 ft. x 8 ft. board—the same as the plywood boards currently used by IDEA. A recycled high density polyethylene (HDPE), also a waste product, binds the rice husks together and provides strength and resistance to humidity.
“While it has taken a lot of trial and error to get a material that is strong and consistent enough to build homes with, we have finally reached a point where we can produce a prototype board that is comparable in terms of strength to commercially available particleboard,” Eckerle said. “Our tests have shown that termites will not eat rice husk or our building material, which will increase the lifespan of the houses in the Philippines”.
Lead photo by CIAT International Center for Tropical Agriculture via Flickr