The seaweed roofs of Læsø are unique. In the 19th century, more than 300 houses were roofed with seaweed, but today only around twenty remain. In 2008, a long-term project was launched to ensure the replacement of the remaining roofs and preserve this building tradition for generations to come.
In fact, it is eelgrass rather than seaweed that is used for the roofs. Eelgrass grows on the seabed along all Danish coastlines except the west coast of Jutland. Due to its high salt content, eelgrass is non-flammable. Over time, like other organic materials, it does break down and the roof naturally needs renewal. Experience shows that seaweed roofs can last between 150 and 250 years.
This film shows the thatching of a seaweed roof using the original techniques.