Cork is a purely natural insulating material that is acquired from the bark of the cork oak. It possesses numerous natural capabilities that are hard to find in other insulating materials. Cork features no diffusion barrier and is therefore purely made up of cells that are sealed by the air. Cork weighs hardly anything as a result of this, although it still features a high level of dimensional stability, even under extreme pressure. Cork is thermally inert since it consists almost entirely of cells filled with air, making it the perfect insulating material. Its capabilities are rounded off by its impermeability to water and resistance to pests and heat.
It is hardly surprising that cork is such a perfect insulating material when you consider that it has all these features. And it has also been proven that cork is one of the most sustainable natural materials.