Kathryn Larsen is an architectural technologist who focused her dissertation on seaweed architecture in Denmark. She was inspired by the old method of seaweed thatching from Læsø, a technique that was nearly lost over time.
Right now, the Læsø houses are being restored by master thatcher Henning Johansen, and preservation efforts are increasing. Most of the information available is only in Danish, so Larsen translated a variety of sources into English for her dissertation. She hopes that it can be a resource for others who want to learn about seaweed as a building material.
As a part of her research, Larsen developed a way to bring seaweed thatching to the modern construction industry. Eelgrass is a fantastic material that is naturally fireproof, rot resistant, carbon negative, and becomes waterproof entirely after about a year. It also insulates comparably with rockwool. Plants grow in it, giving the effect of a green roof. It a material that should be considered seriously in an era of climate change.
Larsen started with sketch models and experimented with different binders, and grid spacing. Then, she created prefabricated seaweed thatched panels, that can be installed as roof or facade panels. To test the panels, she created an installation on the terrasse roof of Copenhagen School of Business and Design (KEA) , in Copenhagen. The installation will stand for at least a year, in order to test the design against wind and weathering. The installation was sponsored by KEA Campus Service, and all material testing was done with the guidance of Material Design Lab. After about eight months outside, the panels are almost entirely intact, and moss is beginning to grow on the seaweed.
In 2019, Larsen received funding from Boligfondens Spirekasse, to build new prototypes and continue her research. She hopes to test the panels’ u-values, to see what insulation properties they can bring to a construction.
Learn more at Kathryn Larsen.