Materials must be durable in order to withstand the test of time and costly replacements which further pollute the environment with waste, (Chiras 2008). In general, manufacturers try to present a variety of usable green materials which are produced with the least amount of energy possible. When thinking of the energy needed to create a product, one must take into account that of extracting raw materials, processing, and transportation of the finished product to the building site, (Environmental Protection Agency 2008). Recycled materials are also highly favored in the construction of green roofing. Such recycled materials include newsprint, sawdust, cement, recycled rubber, and agricultural fibers, (Snell & Callahan 2005).
This soil then serves as a barrier between the elements, along with providing a whole different space for gardens and also provides a brilliant attack on the problem of storm water management, (Environmental Protection Agency 2008). Other layers of the roof include root barriers, drainage, and irrigation systems. These soil-based roofs of vegetation also help reduce sewage loads, absorb air pollution and CO2, along with help insulating the residence to reduce outside noise entering into the context of the home. Especially seen in buildings utilizing soil roofs, there is a natural increase in the weight of the roof to the overall building below it. This soil-based system adds an extra 80-150 lbs per square foot onto the previous load of the building itself, (Environmental Protection Agency 2008). One can still use lumber in
