Natural construction materials are a good alternative to traditional materials derived from finite resources, which are easier to recycle than concrete or cement. Danish designer Kathryn Larsen has created panels from eelgrass, a seaweed that has been used in traditional Danish construction methods. Her prefabricated panels, which are currently being tested on the roof of the Copenhagen School of Business, are waterproof, durable and 100% made from natural materials: timber, seaweed, and water.

Almost all traditional construction materials are being reconsidered, as there is more and more environmental concern regarding the production of concrete. Concrete production creates about a ton of CO2 emissions for each ton of concrete that has been produced, and it uses many non-renewable materials such as sand and minerals. This is a challenge because it is very hard to replenish those resources, and the reuse of construction materials is difficult after their use, making them an obstacle to circular construction.

Natural construction materials are a way out of the use of concrete. They are usually renewable, and often produce a lot less emissions in production. Danish designer Kathryn Larsen was inspired by the traditional way of using seagrass as a roofing material on the Danish island of Læsø to create a roof tile with eelgrass, a sea plant that grows abundantly around Northern Europe. It is created only from timber, eelgrass and water, and does not affect the eelgrass population as it uses dead grass that is washed up on the shore.