Any insulation material can be used. A great super insulation system that meets sustainability requirements is a technique called straw bale construction. Bales of straw are stacked like giant blocks on a standard foundation, either as the building framework or as filler between wood framing. The bales are then pinned to each other using various techniques. Once the walls have settled, they can be finished with stucco, plaster or other conventional sidings.
Straw bales are a natural, safe, locally available and annually renewable material.
Homes built using this technique offer insulation values of up to R-45 and can be constructed using unskilled labor. This technique also helps to support local farm economies, reduces fuel dependence, is economical, can last 100 years or more and creates beautiful and comfortable spaces. When considering roof systems, there are a number of alternatives. Most will last 50 years or more and are made from recycled materials. The most common is metal roofing having 50 percent or better recycled content.