materials can be categorized in any number of complementary ways depending on the kind of building, its climate, its specific design, etc. Crowther (2001) suggests it is helpful at times to break down buildings into a threefold systems, product and material conceptualization, examining a range of different concerns in each area. End of life scenarios can also be explored according to a fourfold framework of building reuse or relocation; component reuse or relocation in a new building; material reuse in the manufacture of new component; and material recycling into new materials. Figure 15 charts this kind of alternative to the existing linear throughput path.