Environmental, economic and energy life cycle assessment “from cradle to cradle” (3E-C2C) of flat roofs

Abstract

The aim of this paper is to evaluate the environmental, economic and energy (3E) performance of different flat roofs solutions, from “cradle to cradle” (C2C), in order to support the selection of the best alternative to be used in each building. Firstly, each of the 3E dimensions is assessed individually using the 3E-C2C method. Then, their aggregated assessment is presented, using the 3E cost-C2C methodology. A group of 114 flat roofs was studied considering a service life of 50 years, including inverted and traditional roofs with limited access and accessible to people, and inverted roofs accessible to vehicles.The results showed that inverted solutions of flat roofs have, in general, worse environmental performance than traditional solutions. Moreover, the 3E assessment confirmed higher costs of solutions accessible to vehicles and lower ones of those with limited access. Furthermore, solutions with higher initial costs demanded lower maintenance costs. Finally, the 3E aggregated assessment allowed confirming the relevant importance of the economic costs throughout the life cycle for all types of accessibility (63%–77%) and its high dependency on the market acquisition costs of the materials of each solution (52%–76%). Environmental costs showed an influence from 12% to 29% and the energy costs between 8% and 13%.