Sustainable, or “green,” buildings – buildings that are deliberately designed to use natural resources in a way that’s environmentally friendly — are no longer a luxury. They are an imperative.
Consider the facts: According to the National Institute of Building Sciences’ Whole Building Design Guide, “On an annual basis, buildings in the United States consume 39 percent of America’s energy and 68 percent of its electricity. Furthermore, buildings emit 38 percent of the carbon dioxide (the primary greenhouse gas associated with climate change), 49 percent of the sulfur dioxide, and 25 percent of the nitrogen oxides found in the air. Currently, the vast majority of this energy is produced from non-renewable, fossil fuel resources…”
Of the two ways to reduce heating, cooling and lighting loads “through climate-responsive design and construction practices,” the Whole residential design build Building Design Guide recommends the use of “high-performance building envelopes: select walls, roofs, and other assemblies based on long-term insulation, and durability requirements.”
One of the most sustainable, high performance building materials prevalent throughout the world is zinc.
Zinc is reported to be the 23rd most abundant element in the earth’s crust. It is a non-ferrous metal that is not susceptible to rust or corrosion: It’s weatherproof, seismic proof, corrosion resistant, and immune to the harmful effects of UV rays, ensuring a very long service life without degradation.
This is possible because architectural zinc develops its own protective layer, which is called zinc hydroxyl carbonate. Once it’s formed, that layer blocks moisture and chemicals from penetrating the zinc and, if it’s scratched, the hydroxyl carbonate will reform over time. In other words, zinc heals itself. That’s why zinc walls and roofs last on average from 80 to 100 years.
Zinc also requires very little energy to manufacture and little to no maintenance, and it is 100 percent recyclable from new construction scrap to the time it reaches its end use. As a result, zinc roofs and wall cladding never end up in landfills.
For generations, European architects have specified zinc as a building envelope material for all types of buildings because it would last and endure harsh weather conditions. In the late 1700s, zinc was also one of the most popular materials used for roofing in America, which is why many well-known historic structures, such as the Washington Monument and Thomas Jefferson’s Monticello, had metal roofs.
Unfortunately, zinc fell out of favor in the U.S. as less expensive roofing materials evolved, such as asphalt shingles, and as American developers and building owners lapsed into a “throw-away” mind-set in the 1960s and ’70s that still assumes no more than a 30- to 50-year life span for American buildings.
Today, American architects are becoming more enamored with the material, not only for its durability but also because of the increasing need for environmentally sustainable design and construction.