Eelgrass thatched panel

Kathryn Larsen

This design is inspired by the traditional application of the seaweed on roofs on island Læsø, Denmark. The washed up seaweed is placed in a field to dry. The panels consist of a frame of wood and steel that is covered with braided eelgrass. Each panel is designed for disassembly; the materials can easily be separated and recycled or reused. At the end of its life, the eelgrass can be used as a fertilizer.

The eelgrass roof is made of:

  • Eelgrass: 70%
  • Wood: 20%
  • Metal grid: 10%

All materials are sourced from Denmark.

Production Process

  • Eelgrass is harvested during autumn in Denmark by seaweed farmers, who harvest the eelgrass after it washes up onshore.
  • If the weather allows it the eelgrass is put on a field to dry for 2 weeks.
  • The wood and metal grid become a support for the eelgrass to be thatched upon. The wood becomes a frame that can then be easily installed on site.
  • Each panel is designed for disassembly. The materials can be easily separated and recycled or re-used.


  • Læsø, traditional seaweed homes
  •  As cladding on roof and facades, eelgrass can also be applied to wall cavities and used in breathable construction as an insulation material.
  • Panels can also be applied to an interior as an acoustic solution.

Environmental impact

The eelgrass and wood used for these panels are biobased. The carbon footprint depends on where these materials are sourced and transported to. The galvanized steel mesh has the largest carbon footprint, but is also the smallest component of the panel

Eelgrass roofs have been around for ages!

Growth Opportunities

This product is still in an experimental phase. Research is being conducted to pass formal tests in order to meet industry standards. Start-up support, access to trained thatchers and the market would be beneficial to this process.


Vaporless construction, non-toxic.

Also nice!

The material is made in Denmark, and all tradespeople involved with the creation of the panels receive labor-market standard wages.

Designer website/contact

Instagram @theseaweedgirl