Researchers convert seaweed into insulation material

For many coastal dwellers, seaweed washed up on the shore is nothing but a nuisance. But this raw material has proven itself capable of keeping buildings well insulated. Together with industry partners, researchers have succeeded in turning it into insulation.

Throughout fall, winter and spring, Mediterranean beaches are littered with little balls of seaweed leaves from the Posidonia oceanica plant, more commonly known as Neptune grass.

Although the natural material of these Neptune balls is regarded as a waste product and generally ends up as landfill, this readily abundant and renewable material is far too valuable to be thrown away.

It displays a variety of characteristics that make it of interest to the building trade - seaweeds are virtually non-flammable, resistant to mold, and can be used as insulating material without the need for chemical additives. It can be used as insulation between the rafters of pitched roofs, to insulate interior walls, or to reduce the amount of heat lost through building envelopes.

Its fibre act as a buffer, absorbing water vapour and releasing it again without impairing its own ability to keep the building insulated. And with a salt content of just 0.5 to 2 per cent, Neptune balls can be used to produce insulation material that will not rot away.

But how exactly is seaweed processed into a building material? A difficult task indeed as it is not easy to remove adherent sand from the Neptune balls, added to which, individual fibres tend to easily cling on to anything including one another and are quick to form new clumps, both during processing and later when being blown into spaces that need insulation.