We use marine grade structural aluminium alloy which is five times as strong as steel and half the weight. This results in the use of only about a quarter the amount of material as it would take with steel and about a tenth as timber. The alloy we use is made from at least 15% recycled material. The mining and extraction process is heavily monitored in Australia and complete land rehabilitation is required. We prefer to use alloy smelted by low impact energy sources (hydro or geothermal). We use low energy cutting and welding systems. The material doesn’t need priming, painting or protection from the elements. It has a very long life even in extreme exposure locations. It can be readily recycled. It is termite proof. It is lightweight and strong and has a dramatically reduced transportation impact over any other material. The EcoCost sytem has determined that this results in a considerably lower overall environmental impact than any other available materials.