Life cycle assessment and costing of carbon neutral hybrid-timber building renovation systems: Three applications in the Republic of Korea

Abstract

Building renovation must be attractive and profitable regarding sustainability criteria to be a competitive alternative to demolishment and construction of new buildings. This study presents the global warming potential related life cycle assessment and net present value life cycle costing of three hybrid-timber building renovation and extension systems. The three systems have been developed for three common building types in the Republic of Korea: residential high-rise (cross-laminated timber system), multi-use (glue-laminated and timber frame system), and residential low-rise (steel and timber frame system). The global warming potential of the renovation systems’ materials and their net present value has been calculated with a parametric design system that facilitates the streamlined calculation of multiple construction options and the resulting environmental and economic impacts. The results demonstrate that the three systems achieve negative global warming potential (apartment: −4.74 kgCO2/m2, mixed-use −0.74 kgCO2/m2, multi-unit: −0.28 kgCO2/m2). Positive net present value can be achieved by selling or renting additional useable floor space created through building extension and renovation, resulting in economically and ecologically profitable alternatives to new construction. The parametric calculation system facilitates integrated economic and ecologic cost assessment and evaluation and allows for multiple scenario comparisons.