Denmark's Seaweed Roofs

Denmark’s Seaweed Roofs

Pavel Gonchar Renoteck News, Roofing Resources

Around the world people have come up with unique ways to provide a roof over their head. Some imagination had to be used if typical materials were not available. The Danes used seaweed roofs!

On  Læsø, a small island in Denmark, deforestation forced the people to look for roofing and building alternatives.
During the middle ages a robust salt industry developed on the island. To process the salt, kilns were needed that required constant fueling. The end result was the loss of wood needed to build their homes.

The islanders solution was a seaweed called eelgrass, combined with driftwood. The seaweed lasts close to 300 years, due to its high salt content which prevents decay. Homes dating back to the 1600s are testament to the longevity of this material. The salt in the seaweed also acts as a fire retardant.

In the 1930’s disease attacked the eelgrass leading to a decline in this roofing method. While the seaweed homes previously numbered in the 100’s only about 20 still remain. A heritage project initiated in 2009 reintroduced the  cultivation, harvesting and preparation of eelgrass to farmers in Southern Denmark. While an eelgrass roof costs 4 times that of a straw thatched roof, it lasts 200-400 years. Straw thatch lasts 30-40 years.

Modern Seaweed Roof and Home

Modern Seaweed Roof and Home

Today the structural system has evolved into knitted wool pillows stuffed with the seaweed.
It is considered by some to be the “ultimate sustainable material.” The features of seaweed are numerous.

  • Yearly reproduction in the sea
  • Comes to shore unaided
  • Is dried out by the sun and wind when spread out in fields
  • Excellent insulating properties
  • Non toxic
  • Fireproof
  • Extensive life span
  • co2 reducing
  • Environmentally friendly
  • Acoustic properties
  • Naturally regulates indoor humidity

When choosing your roofing material for Alberta’s difficult environment, let Renoteck help you with the decision making process.

A Modern Take on the Traditional Seaweed House

A Modern Take on the Traditional Seaweed House