Influence of service life of building components for flat roofs in the environmental and economic performance during life cycle

With the principal aim of reducing energy consumptions from which the building sector is primary responsible together with the continuous deterioration of the actual building stock, renovation has become the key factor to achieve small and large-scale improvements in housing and environmental quality. This research uses Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) methodologies to compare the environmental and economic performance of different types of flat roofs commonly used in The Netherlands. The main goal of this research is to give information about the environmental and economic performance of certain building materials and components and to analyse in what extent this performance is influenced by the material’s service lives in order to facilitate choices that will improve the environmental performance in the housing sector remaining economically competitive. The case of study is a typical residential building situated in The Netherlands and considers the environmental impacts of materials, energy consumptions for heating, and maintenance activities. The comparisons shows environmental performance from a theoretical and real practice data, in which a sensitivity analysis is applied to the service lives of selected layer into three levels. From the environmental and economic point of view EPS is the best insulation material option together with PVC roofing if a gravel ballast is used as covering layer, otherwise with White Bitumen roofing when there is no covering layer. All materials presented significant environmental performance improvements when their service lives where extended. Energy consumption for heating is the major contributor to the total roof environmental burden and contains the environmental improvements influenced by service lives extensions. Results shows which roof conformations are more environmental and economic sustainable and how are the impact shares during the whole life cycle. This research gives information to all actors involved in the building sectors about how to reduce environmental impacts of existing housing stock.