The International Journal of Life Cycle Assessment vol:17 issue:6 pages:813-827
Purpose The goal of the study was to determine the preferred
composition of the floor on grade in residential buildings
in the Belgian context from a life cycle environmental and financial perspective. In addition to the life cycle costs, the required investments were evaluated to take into account budget restrictions. The analysis of current available materials and techniques allows both the designer and building owner to extend their decision criteria from mainly investment cost to life cycle aspects as well. Methods In this study, the potential environmental impact was assessed by considering the environmental external cost of the floors. Several existing methods were combined to enable a full assessment, taking the ExternE methodology (willingness to pay) as the main base. The ecoinvent database was used to gather the inventory data but was adapted to increase the representativeness for Belgium. The financial evaluation included both the investment and life cycle aspects. The latter was analysed through the sum of the present values of all costs occurring during the life span of the floor.
Results and discussion The necessary assumptions (e.g.
transport, end-of-life treatment, cleaning, life span, economic parameters) and the adaptations to the ecoinvent data are transparently reported. The methodological steps (e.g. monetary valuation, transmission losses, equivalent degree days, Pareto optimisation) are elaborated in detail. This allows the results, which are graphically presented, to be correctly interpreted. The contribution of the life cycle stages and the optimisation potential of the considered impacts are discussed.
Conclusions The environmental external cost based on the
willingness to pay to reduce environmental impacts proved to be relatively low, representing about 9 % of the financial cost. The cost reduction of current common practice was estimated to be about 20 and 60 % from a financial and environmental perspective, respectively. The insulation level and the floor covering were identified as the most important optimisation parameters.
Recommendations Internalisation of environmental external
costs might be an important step to achieve more sustainable
solutions. However, it is recommended to consider financial
and environmental external costs separately too because both contain important information for the decision maker.
Because it is hard (if not impossible) to increase the insulation level of the floor on grade later on in the life cycle of the building, a high insulation value should be a priority during construction. The floor covering can more easily be adapted and is thus considered a secondary priority.