Materials Selection in Framing: Steel?

Lead Author: Dr. Jim Bowyer

Publish date: 04.24.2007

 

Is Steel Framing a Good Environmental Choice?

 

Suppose that in designing a residential home, you have an objective of minimizing environmental impacts. Once decisions are made regarding house size and orientation on the site (both factors that have a significant impact on energy consumption and overall environmental impact over the life of the structure), one of the first issues to be resolved is selection of framing materials. A question that often arises is: Is it more environmentally responsible to use steel framing instead of wood framing?

 

Although promoted as an environmentally preferable material, and classified as such in several green building programs, the production and use of steel framing results in a number of adverse environmental impacts that greatly exceed the impacts of available renewable alternatives such as wood. Even when considering steel framing that contains recycled content as high as 35 percent, considerable energy is consumed in the production process and places steel products near the top of any embodied energy ranking of construction materials. The high conductivity of steel and associated need for energy-intensive insulation adds to the environmental burden of steel-framed structures. Finally, high energy intensity and manufacturing processes unique to steel translate to very high levels of emissions to air and water and global warming potentials. The bottom line of this analysis is that it is rarely appropriate to characterize steel as the more environmentally benign material when compared to wood. Additionally, the take home message is that evaluating the impacts of a material and comparing alternatives needs to be a thoughtful and holistic process that does not rely on individual attributes. The use of existing and readily available life cycle assessment data offers the opportunity to efficiently accomplish this more thoughtful analysis.