Building Green

+ Story by Paul Dunker
+ Photography by Paul Dunker

Examining the impacts of alternative building styles.

Call it trendy, call it fashion, call it responsible, sustainable, “green,” or just plain common sense. It’s about being aware of the repercussions of our everyday choices, and it’s about time.

According to the U.S. Green Building Council, here in the United States buildings account for 36% of total energy use, (65% when you look solely at electricity,) 30% of greenhouse gas emissions, 30% of raw materials use, 30% of waste output (136 million tons annually) and 12% of potable water consumption. The choices we make about how our buildings are constructed—materials, location, energy consumption,
waste generation, even the distance materials travel to get to the site—have a tremendous impact on the planet. It’s a complicated scenario requiring diligence, commitment and a willingness to make tough decisions, but we can make a difference.

How It’s Built
The term “embodied energy” refers to the total amount of energy expended to produce a particular building material or set of components, even a whole house. Crews of carpenters, concrete workers, plumbers, electricians, etc., have built most housing in this country on site, one stick at a time. Every one of them drives to the jobsite every day, has their materials delivered a little at a time, and runs out to the lumberyard themselves when they forget something. So that stick-built house “embodies” not only the energy used to manufacture all of the materials the house is built from, but all those vehicle trips as well.

Prefabrication is one way to lessen this impact. Whether it’s panelized construction such as Structural Insulated Panels (SIPs) or modular construction, most of the work is performed in a controlled factory setting. Materials are delivered in bulk and workers can carpool or take public transportation. SIPs consist of two layers of structural sheathing laminated around an insulating foam core and look like big plywood ice cream sandwiches. A common misconception with modular construction is that it applies only to mass-produced, “cookie cutter” mobile homes. Quite the opposite is true. Modular construction techniques can be used on almost any custom home design as long as the prefabricated pieces, or “modules,” are limited to a certain size. Modular building allows materials to be used very efficiently, and the dimensions of each project are similar enough that they can be engineered to minimize scrap. The minimal waste that is generated is usually shipped to recycling facilities. Compare that to the dumpsters and burn piles found outside of a typical stick-built home, then multiply it by the number of new homes you see under construction in a year, and you can begin to visualize the 136 million tons I mentioned earlier.

What It’s Made Of
You might automatically think “recycled is better,” and in many instances you’re right. Recycled timbers milled from lumber originally used in large warehouses, factories, even railroad trestles, can be resawn and find their way into almost any type of new home. There are “engineered” building products produced from industrial waste gaining acceptance in home design as well. Rastra Block, Parallam beams, countertops made from ground beer bottles, insulation made from discarded jeans. You name it; they’re all a step in the right direction.

Not everything recycled, however, is inherently “green.” You also need to think about the energy used to turn whatever the material was in its former life into whatever it has become. When you consider this, perhaps using steel studs made from melted down car bodies isn’t as appealing as originally thought. The same might be said for Insulated Concrete Form (ICF) construction, another recent trend in home building. These are prefabricated blocks of Styrofoam which get stacked like Legos, reinforced, then filled with concrete. The embodied energy issue here is the tremendous amount expended to produce Portland cement and the carbon dioxide this process releases into the atmosphere.

When you get right down to it, traditional wood studs stack up pretty well to recycled materials in terms
of sustainability, depending of course on harvesting practices. Wood studs today are generally harvested from small diameter farmed trees, which are replanted once they’re cut down. While they’re alive they’re filtering our atmosphere, and they don’t require a large amount of energy to produce.

Along the same lines we have the epitome of green building: straw bale construction. Here, stacks of hay bales are used for super-insulated exterior walls, covered with stucco inside and out, and usually interspersed with structural timbers to support the roof load and frame door and window openings. The drawback is that this type of construction is generally limited to single story buildings.

Whatever your decision, be sure to hire a professional familiar with current green building practices.