Environmental Impacts of Building Construction Using Cross-laminated Timber Panel Construction Method: A Case of the Research Building in Kyushu, Japan

Abstract

In Japan, there has been an increase in the number of buildings built using cross-laminated timber (CLT) in order to utilize the abundant forest resources in the country. However, no studies have evaluated the environmental impact of the construction of CLT buildings in Japan. This study evaluates the environmental impacts from the start of construction to the completion of a real CLT building in Kumamoto city, Kyushu region, southern Japan. We investigated the input of the materials and energy used in the construction of the building. The environmental impact categories evaluated include climate change, ozone layer depletion, eutrophication, acidification, and photochemical oxidation. We found that the concrete used for the foundations, and the cement-based soil stabilizer used for ground reinforcement accounted for 42% of the greenhouse gas (GHG) emissions. The construction site was previously used as a seedbed field, necessitating ground reinforcement. Furthermore, the large foundations were designed in order to raise the low height of the wooden structure from the ground level. Developing and applying methods with lower environmental impacts for ground reinforcement and building foundations is recommended. In addition, we found that by using biomass-derived electricity in CLT manufacturing, the environmental impacts of CLT manufacturing could be reduced, thus reducing the environmental impacts of the entire building. The biogenic carbon fixed in the wooden parts during the building usage accounted for 32% of the total GHG emissions of the building construction. Since this biogenic carbon will be released to the atmosphere at the end-of-life stage of the building, a long-term usage of the CLT buildings and/or reuse of the CLT is recommended.

Carbon storage in the built environment: a review

“…Furthermore, the market for some wooden products does not yet exist because modern technologies cannot immediately compete against established technologies (Hildebrandt et al 2017). Urban governors have a primary role in managing cities and planning future developments by setting efficient policies (Stocchero et al 2017) and taking a lead in encouraging the use of bio-based materials by demanding their use more widely through planning and land use policies (Hildebrandt et al 2017, Nakano et al 2020, Piccardo et al 2021. The current climate policy is too weak and therefore it´s important to intensify efforts to identify and manage both soft (organization) and hard (technology) barriers (Karlsson et al 2020).…”

“…Therefore timber´s potential as a lower-impact alternative to concrete and steel is dependent on sustainable forest management (Hawkins et al 2021). Wood can be used sustainably if it does not exceed the rate of forest regeneration (Nakano et al 2020). Material efficiency and carbon storage capacity should always be considered when using wood material (Hafner and Schäfer 2018).…”

Carbon sequestration and storage in the built environment

“…Several others focus on normalised units of floor area (e.g. 1m 2 ) for whole building case studies (Hafner and Schäfer, 2017;Nakano et al, 2020;Padilla-Rivera et al, 2018;Pierobon et al, 2019;Ximenes and Grant, 2013). These studies, and therefore their findings, are however difficult to compare mainly due to differences in the choices of functional units, different system boundaries, and different ways of reporting results.…”

Panorama internacional e nacional do uso e aplicação do sistema construtivo Cross Laminated Timber – CLT

“…Os fabricantes devem ter seu processo produtivo aprovado pela JAS n° 3079. No momento, existiem 8 unidades produtoras de CLT certificadas no Japão, com volume anual total de produção em torno de 63.000 m³ (NAKANO, KARUBE, HATTORI, 2020;HUZITA et al, 2022).…”