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Comparative life-cycle assessment of a mass timber building and concrete alternative

Formally Refereed
Authors: Shaobo Liang, Hongmei Gu, Richard Bergman, Stephen S. Kelley
Year: 2020
Type: Scientific Journal (JRNL)
Station: Forest Products Laboratory
Source: Wood and Fiber Science. 52(2): 217-229.

Abstract

The US housing construction market consumes vast amounts of resources, with most structural elements derived from wood, a renewable and sustainable resource. The same cannot be said for all nonresidential or high-rise buildings, which are primarily made of concrete and steel. As part of continuous environmental improvement processes, building life-cycle assessment (LCA) is a useful tool to compare the environmental footprint of building structures. This study is a comparative LCA of an 8360-m2, 12-story mixed-use apartment/office building designed for Portland, OR, and constructed from mainly mass timber. The designed mass timber building had a relatively lightweight structural frame that used 1782 m3 of cross-laminated timber (CLT) and 557 m3 of glue-laminated timber (glulam) and associated materials, which replaced approximately 58% of concrete and 72% of rebar that would have been used in a conventional building. Compared with a similar concrete building, the mass timber building had 18%, 1%, and 47% reduction in the impact categories of global warming, ozone depletion, and eutrophication, respectively, for the A1-A5 building LCA. The use of CLT and glulam materials substantially decreased the carbon footprint of the building, although it consumed more primary energy compared with a similar concrete building. The impacts for themass timber building were affected by large amounts of gypsumboard, which accounted for 16% of total building mass. Both lowering the amount of gypsum and keeping the mass timber production close to the construction site could lower the overall environmental footprint of the mass timber building.

Keywords

Cross-laminated timber, environmental assessment, life-cycle analysis, tall wood building

Citation

Liang, Shaobo; Gu, Hongmei; Bergman, Richard; Kelley, Stephen S. 2020. Comparative life-cycle assessment of a mass timber building and concrete alternative. Wood and Fiber Science. 52(2): 217-229.
https://www.fs.usda.gov/research/treesearch/60137