Steel, concrete, aluminum and glass have been the predominate materials used in large commercial buildings for more than a century. The first steel-framed skyscraper was the Home Insurance Building built in Chicago in 1885. The use of these materials has allowed buildings of today to be tall, lightweight, fire-resistant, and incredibly efficient.
Until very recently, there has not been much of a reason to challenge the use of these materials in buildings. Our ever-growing understanding of the negative impacts our species has had on the environment is forcing a rethinking of everything we do, including the materials we use to build with. Steel, concrete, aluminum, and glass all require a huge amount of energy to produce. And they are used in great quantity in buildings as structure and skin. According to the paper “Life-Cycle Energy Use in Office Buildings,” by Raymond J. Cole and Paul C. Kernan, structure and envelope represent the single largest component of a building’s total embodied energy. As a result, these four materials represent the largest contribution to green house gas emissions in buildings. And this is a big deal. So much so that the current version of CALGreen—the State of California’s Green Building Code—includes provisions for calculating a building’s contribution to climate change (GHG), using either whole building analysis or materials analysis. For the materials analysis path, the code states: