Superwood is spruce impregnated with fungicide and preservative to make it suitable for exterior use. Conventional impregnation applies force to liquid to treat the outermost layer of wood and so any cut or damage exposes the bare timber beneath. Superwood have developed a different technique, which allows them to apply treatment throughout the thickness of the timber, making it more efficient and effective. They take locally sourced spruce and apply the treatment using carbon dioxide (CO2) at temperature and pressure that causes it to become supercritical. In this state, there is no surface tension and the CO2 is able to pass through the wood without resistance, carrying the preservative chemistry and impregnating the wood from within. The colour of the wood is unaffected by the treatment, and will develop a typical silver patina over time, which allows light colour paints and stains to be used.

Superwood is spruce impregnated with fungicide and preservative to make it suitable for exterior use. Conventional impregnation applies force to liquid to treat the outermost layer of wood and so any cut or damage exposes the bare timber beneath. Superwood have developed a different technique, which allows them to apply treatment throughout the thickness of the timber, making it more efficient and effective. They take locally sourced spruce and apply the treatment using carbon dioxide (CO2) at temperature and pressure that causes it to become supercritical. In this state, there is no surface tension and the CO2 is able to pass through the wood without resistance, carrying the preservative chemistry and impregnating the wood from within. The colour of the wood is unaffected by the treatment, and will develop a typical silver patina over time, which allows light colour paints and stains to be used.

Press-impregnated pine stairwell and walkway. The colour has faded over time to look like untreated wood.