Reducing Embodied Energy of Floor Assembly: A Case for Using CLT in Mid-Rise Residential Buildings

Buildings’ energy consumption is estimated between 30 and 40% of its global use, resulting in various environmental impacts. There is a need to reduce the energy consumption by buildings in the construction phase, along with the operation phase, which is well-studied. Concrete is a construction material that is being used widely in the construction industry but has high embodied energy. In the move towards using low-energy materials, new materials and construction technologies are being developed and studied. In this regard, Cross lamented timber (CLT) can be a sustainable alternative due to its excellent load-carrying capabilities, and therefore has become an emerging choice in buildings as a low embodied energy material alternative. This paper aims to explore the potential initial embodied energy reduction benefits by comparing the initial embodied energy consumption of concrete floor systems and CLT floor systems for mid-rise residential buildings. An eight-story apartment building was used for this analysis. This study shows that replacing the reinforced concrete floor with a CLT floor results in more than four times reduction in embodied energy associated with floor construction. This demonstrates the need for careful selection of materials in buildings at the design stage to reduce their embodied energy and consider the use of CLT instead of reinforced concrete in this context. Results from this initial study also indicate the need for more studies to address the challenges associated with the adoption of this low embodied energy material.