| Analyzing the 75-year life cycle of a typical home, a new study conducted by 15 U.S. universities and research institutes revealed that wood-framed homes are more environmentally friendly than those constructed of steel or concrete. Additionally, the researchers, known as the Consortium for Research on Renewable Industrial Materials (CORRIM), concluded that the bulk of energy required to build an average home is consumed during the manufacture of building materials - not during actual construction.
"These are landmark findings," said Kelly McCloskey, president and CEO of the Wood Promotion Network. "This offers a first-ever snapshot into how building materials impact our environment."
Twenty-three independent researchers collaborated on the project that used a process called life cycle assessment to weigh the environmental impact of home construction. Life cycle assessment gauges the energy required to produce building materials, as well as construct, maintain and demolish a typical home over a period of 75 years. "Considering 1.7 million homes using wood, steel and concrete are constructed each year, choosing construction materials wisely is significant," said study participant Bruce Lippke, professor of forest resources, University of Washington. "The manufacture of these construction materials requires as much energy as heating and cooling 10 million or more homes annually." The CORRIM research evaluated the life cycle of a hypothetical wood and steel-frame home in Minneapolis, as well as a wood and concrete-frame home in Atlanta. The study determined that the construction of the Minneapolis steel-frame home used 17% more energy than the matching wood-frame home, and the Atlanta concrete-frame home used 16% more energy than a matching wood-frame house. The energy tallied for the study included everything in the life cycle of a home, including: electricity used by the homeowner, diesel and fuel oil to extract and haul materials, natural gas to generate steam in lumber mills and electricity for steel mills. "Everything kind of flows from energy consumption," Lippke says. "If you're using energy, you're polluting water, polluting air and kicking out carbon dioxide emissions."
The study also concluded that the carbon emissions associated with energy use represent one of the more important environmental impacts. The researchers considered, for example, carbon dioxide, methane and nitrous oxide emissions generated during the life cycles of the homes, as well as the length of time these greenhouse gases linger in the atmosphere to determine the global warming potential of different construction materials. They estimated the global-warming potential of the steel-frame home to be 26% higher than the wood-frame, and the concrete-frame home was 31% higher than the comparable wood-frame. "The use of wood products instead of steel or concrete can farther reduce the greenhouse emissions from fossil fuels wherever lumber mills generate power and heat using bark, sawdust and other byproducts of milling," said Lippke. "More than half the energy required by mills currently comes from these residuals, a renewable source of energy compared to fossil fuels like concrete and steel." The report offers additional suggestions on how to help reduce the energy demands of home construction, including:
•Redesigning houses to use less fossil-fuel intensive products
•Changing building codes that result in excessive use of wood, steel and concrete
•Recycling demolition wastes
•Increasing durability of homes through improved products and construction practices For more information visit www.beconstructive.com or http://www.corrim.org
(Thanks to Rick Schumacher, Publisher of LBM Journal for sharing this story with us)
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