Jeffrey Head, LA Times
Woody Harrelson championed the environmental benefits of hemp. Giorgio Armani and Calvin Klein incorporated it into their collections. Now a company promoting hemp as the eco-building material of the moment said it wants to build California's first hemp house.
Hemp Technologies said it wants to use hemp-based materials to construct a 500-square-foot structure at the ruins of Knapp's Castle near Santa Barbara. The castle, completed in 1920, was built for Union Carbide founder George Owen Knapp but destroyed by wildfire in 1940. Since then, all that has remained on the property are the sandstone blocks outlining the once-grand estate.
The principal material for the project is Hempcrete, made of the woody internal stem of the Cannabis sativa plant, which is processed into chips and mixed with a lime-based binder. That concoction is then sprayed on, poured into slabs or formed into blocks like concrete to create the shell of a building. Interior surfaces are plastered, and exterior surfaces are stuccoed.
“The walls are to be framed and earthquake-braced internally with lumber,” said Greg Flavall, Hemp Technologies' co-founder, who added that “hemp is very close in cellulosic value to wood.” The material helps to keep structures warm in winter and cool in summer, he said.