Multi-criteria Decision Analysis of a Building Element Integrating Energy Use, Environmental, Economic and Aesthetic Parameters in Its Life Cycle

Abstract

With the increasing concern of the building environmental impacts, governmental regulation and people own consciousness have shown rising interest in buildings protocols and methods for sustainability certification. Life cycle assessment (LCA) represents a useful tool for designers, companies and building owners in every phase of the construction process, but its daily use encounters several applicability problems. It is indeed hard to take into account crucial parameters regarding the economic, aesthetic and energetic performances of each alternative in a whole sight. The aim of this paper is to exploit LCA techniques to evaluate the environmental impacts of three different types of roof analysed within the building component scale. A green, reverse, and simply waterproofed roofs have been drawn and split into each component’s environmental impacts, whereas a multi-criteria decision analysis (MCDA) tool integrating economic, social and aesthetic parameters. LCA results showed that the reversed roof solution gives out the minimum environmental damage (−69, 46% compared to the common waterproofed roof). The results from this LCA analysis are included in a more holist MCDA approach which is able to consider different objectives (thermal performance, construction cost, aesthetic performance, social utility, environmental impact). This integrated evaluation is conducted according to different scenarios and points of view (eco-social and business-as-usual) and gave scenarios with a synoptic assessment of each maximized performance. Conclusive remarks show that an MCDA qualitative analysis coupled with the quantitative result from LCA appeared to be very helpful in comparing options in the design phase of a building, and a useful communication tool among all the stakeholder of the construction process. This new approach based on the LCA-AHP analysis can help decision makers to find sustainable alternatives among available options and promises a more sustainable product or process.