Little Seaweed house

On the Danish island of Læsø, Vandkunsten architecture studio was commissioned to design this holiday house using a local and traditional building material known as… seaweed.

Some people might think of seaweed as an experimental building material. However, the tradition of building with seaweed on the island of Læsø is centuries old. And the tradition exists for good reason.

Seaweed displays some pretty outstanding properties. Highly effective as an insulating material, seaweed is also non-toxic, naturally fireproof, exhibits outstanding acoustic properties and even has the ability to absorb and give off moisture – thus helping to regulate the indoor climate. With a material life-span of 150 years, durability is another plus. As is its availability: it is found in Danish coastal waters in abundance.

The architects strived to blend this vacation home into the surrounds and respect the traditional architecture of a neighbouring seaweed house while expressing a sleek and modern architectural language.

For this modern interpretation of seaweed cladding, seaweed was stuffed into netted bags and then attached to the timber-frame walls and roof of the cottage. Panels of seaweed encased in wood were additionally used to insulate the floor, walls and ceilings.

Lifecycle analysis indicates this house is actually ‘carbon-negative’ as the amount of C02 accumulated by the seaweed walls and roof exceeds the C02 emitted during transportation and production of its building materials. Jørgen Søndermark from Realdania Byg’s, the Danish non-profit organisation that commissioned the vacation home, refers to seaweed as ‘the ultimate sustainable material’.

Building with seaweed is certainly nothing new. But in this era, with an intense focus on climate change and environmental concerns, seaweed may seems like a very ‘modern’ material indeed.

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