Source: Kathryn Larsen/Copenhagen School of Business and DesignA design student at the Copenhagen School of Business and Design in Denmark is turning eelgrass into sustainable building material.

Design student Kathryn Larsen is exploring eelgrass for use as a roofing material, following in the tradition of Vikings, who had used the material to thatch their roofs on the island of Læsø, off the coast of Denmark.

Not to be confused with seaweed, eelgrass is a type of seagrass common all over the U.K. and Scandinavia that is naturally fireproof, carbon negative, rot-resistant and waterproof after one year. Eelgrass also insulates and promotes the growth of plants within it. Based on those characteristics, Larsen devised a modern-day approach to eelgrass thatching, developing prefabricated eelgrass-thatched panels suitable for facades and roofs.

Currently, the panels are in the midst of a one-year trial on the rooftop of the Material Design Lab at the Copenhagen School of Business and Design. At eight months into the year-long study, the eelgrass panels are nearly intact and beginning to yield moss.

Although Larsen recognizes eelgrass levels are currently being depleted, she explained that there are ways to farm and harvest it without impacting the marine ecosystem. As such, Larsen plans to develop more panels over the remainder of the year.

“I hope to test the panels u-values, to see what insulation properties they can bring to construction," explained Larsen of her next steps.