Comparison of Sustainability Performance for Cross Laminated Timber and Concrete

As sustainable building design practices become more prevalent in today’s construction market, designers are looking to alternative materials for novel design strategies. This paper presents a case study comparing the sustainability performance of cross laminated timber (CLT) and reinforced concrete. A comparative sustainability assessment of cross laminated timber and concrete, considering economic, environmental, and social aspects was performed. Environmental impact is measured in terms of CO₂ equivalent, economic impact is measured with total sector cost (including sector interdependencies), and qualitative metrics were considered for social impact. In order to conduct an accurate performance comparison, a functional unit of building facade volume was chosen for each product. For this paper, several end-of-life strategies were modeled for CLT and concrete facades. To understand environmental, economic, and social impact, three different scenarios were analyzed to compare performance of both CLT and concrete, including cradle to gate product manufacturing, manufacturing with landfill end-of-life, and manufacturing with recycling end-of-life. Environmental LCA was modeled using GaBi 5.0 Education Edition, which includes its own database for elements including materials, processes, and transportation. To compare the economic impact, Carnegie Mellon’s EIO-LCA online tool is used. Finally, social life cycle impact was considered by identifying process attributes of both products that affect the social domain. Based on this analysis, the use of CLT has a significantly lower environmental impact than concrete, however there are additional costs.