Environmental Impact Assessment of Light-frame and Timber Frame Structures

The objective of this study was to analyze the environmental performance of different wood structural assemblies for residential buildings. Two structural systems (a traditional timber frame and a light-frame) were compared together with alternate material options for each system. Environmental impacts were determined using the Athena Impact Estimator for Buildings software. Design alterations for generalization were made to an existing timber frame (TF) structure used as the basis of this analysis, and an equivalent light-frame (LF) structure was designed based on the International Residential Code (IRC). Environmental impacts observed include total energy consumption, fossil fuel consumption, global warming potential (GWP), and wood fiber use. All analyses were considered cradle-to-gate, including the manufacturing and construction life-cycle stages. Results show how GWP is linked to both fossil fuel consumption and wood fiber use, and how ultimate environmental impact is driven by energy source. Environmental impacts of structures are driven by material choice, and levels of carbon stored in structural wood serve to decrease GWP. Of the structural assemblies analyzed, the most traditional TF structure outperformed all other options in almost every measure.