Whether you are completely convinced that human activity is causing global warming or think Al Gore invented it the way he did the Internet, you likely are to be involved in a project in the very near future that incorporates sustainability concepts. Sustainability is here to stay and there is no reason to shy away from such projects as long as you understand some of the basics.
Sustainable, or green, construction seems to have reached a critical mass. Governments suddenly have signed on, especially for public and commercial buildings. Tax credits are available in many states and even bankers are getting into the mix. According to USBanker magazine, “Banks like PNC Financial Services and Bank of America are at the forefront of the green-building craze.” And in Europe, the European Union has issued a directive to require new homes to have energy performance certificates—can the United States be far behind?
A Trombe wall has masonry or concrete on the inside that is painted black on the exterior face, an air space, and glass on the exterior of the home. The completed walls look like windows with black shades. Photos: Joe McGovern, Living Designs Group
Concrete can contribute to sustainable construction, according to Portland Cement Association's (PCA) Web site ConcreteThinker.com, in 19 different ways (see Concrete's Sustainability Solutions). Many of these are simply natural attributes of concrete, such as acoustics contributing to quieter rooms, durability, and thermal mass. Others require modifications to the design, materials, and construction, such as the incorporation of recycled materials or energy performance. Concrete contractors may be called on to provide many of these things.HOW GREEN IS GREEN?
Where did “green” come from and why suddenly are we hearing so much about it? This actually has been sneaking up on us for several years, but has gained momentum in the past few. The nation's leading sustainability organization is the United States Green Building Council (USGBC, www.usgbc.org), which was founded in 1993. In 2003 its membership was only about 2000 companies and organizations, but today its membership has skyrocketed to more than 7700, tripling in number the past three years. The USGBC sponsors Greenbuild each year, a conference on sustainable construction scheduled for Chicago, November 7–9, 2007.
Despite its official-sounding name, the USGBC is not a government agency, but rather a nonprofit association. The organization's primary focus has been its Leadership in Environmental and Energy Design (LEED) Green Building Rating System. There's a lot of misunderstanding about LEED: it is not a building code, it is not even a design system, but rather a way to measure how green is green. LEED aspires to look at the entire home and its environment, not only its energy efficiency. Points are awarded for a variety of home features, including such things as where trees are planted and how close the home is to public transportation. Points also are awarded for permeable pavements and the use of local materials (such as locally produced concrete and aggregate). To become a LEED “certified” home, the project needs to gain at least 30 points; 50 points make it a LEED silver project, 70 points gold, and 90 points platinum. In some cases, it seems that designers and builders are incorporating things into projects purely to accumulate LEED points, even if there might be better, more truly sustainable ways.
Although LEED seems to be becoming the standard, it is not the only game in town. There are other perfectly valid ways to measure the sustainability of a home's design and construction. The National Association of Home Builders (which sponsors this magazine through its Concrete Home Building Council) has developed a program they call the Green Building Initiative (GBI, www.thegbi.org). This program incorporates Green Globes, which is an online sustainability rating system similar to LEED. Green Globes originally was developed in Great Britain, then imported to Canada where it is administered by ECD Energy & Environment Ltd. NAHB has adopted Green Globes for home construction.