The deep blue sea might hold the key to more energy efficient buildings through the insulation properties of seaweed.

Architects are looking for ways to implement more and more raw materials into the built environment, a trend that now includes the possibility of seaweed as a natural form of thermal insulation and a way to reduce carbon emissions.

In Australia alone, energy reduction is an ongoing environmental challenge with buildings responsible for approximately 20 per cent of the country’s energy consumption and commercial buildings alone accounting for about 10 per cent of Australia’s total greenhouse gas emissions.

While green building materials such as recycled timber are prioritised in construction, the thermal design of a building can have a powerful effect on the energy performance of a building.

Seaweed could become the latest insulating material used to combat heat loss. The incredibly sustainable renewable material is fireproof, resistant to mould, free of toxins and can be applied in its natural form without the need of chemical additives.

According to a study conducted by the Fraunhofer Institute for Building Physics IBP, seaweed fibres have the ability to hold 2.502 joules per kilogram of energy – 20 per cent higher than wood or wooden products used as insulation.

Washed Up Neptune Balls

Washed Up Neptune Balls

The study involves collecting little balls of seaweed leaves from the Posidonia oceanica plant (also known as Neptune grass) that are available in abundance across Mediterranean beaches.

The institute has noted seaweed’s sustainable properties when used as building insulation “between the rafters of pitched roofs, to insulate interior walls, or to reduce the amount of heat lost through building envelopes.”

While the Neptune balls have been considered waste for years, the institute has found a way to remove sand from the fibres, which enables the seaweed to be “stuffed” or “blown” into spaces in need of insulation.

A company called NeptuTerm e.K is already processing seaweed and distributing it as a means of reducing energy consumption in old and new buildings alike.

The company is also looking to develop “solid, ecologically-sound sheets” that could be appled to roofs, exterior facades, walls and basement ceilings.

Another project on the Danish island of Læsø has combined the underwater material with modern building techniques, cladding a home almost entirely in seaweed.

The project was designed by Vandkunsten in conjunction with Realdania Byg, a non-for-profit preservation group which used seaweed as an alternative to mineral wool to further reduce carbon dioxide emissions.

Seaweed House in Denmark

Seaweed House in Denmark

Seaweed was placed into netted bags and applied vertically and horizontally along the timber walls and roof of the house.

Realdania Byg’s Jørgen Søndermark noted that seaweed replenishes itself regularly and can last as long as 150 years when used as insulation.

Architect Manthey Kula is also involved in ongoing research of exploring dried seaweed as a form of natural thermal insulation.

Kula demonstrated his innovation during the 2011 Norwegian Architecture Festival by applying the product to windows. He now hopes to encourage local industries where seaweed is plentiful to grow, harvest and dry the material, which could then be converted into a sustainable building material.