Embodied energy on refurbishment vs. demolition: A southern Europe case study

Embodied energy on building materials is a concept that allows the measurement of environmental impact, considering energy expenditure associated to the extraction, transport, processing, on-site assembly and performance of materials, during their expected life cycle. Longer service life periods of given materials and derived assemblies correspond to more sustainable practices, as they reduce the impact of energy and resource consumption and the corresponding level of emissions. In this paper, an assessment is made of the cost/benefit ratio associated to two different strategies for intervention on a 40 year old detached single house in Portugal: total demolition vs. refurbishment. Since the building cost of both strategies of intervention was estimated to be similar, environmental impact was considered as a decision criteria. Therefore, an analysis was made of the initial embodied energy, new materials and materials sent to landfill, for two different scenarios: (a) integral substitution of the existing structure by a new house, and (b) partial demolition and refurbishment of existing house. The original house was characterized to provide a benchmark for the comparison of both intervention strategies. In the end, data related to energy and mass were used to sustain a decision regarding the recommended type of intervention.