Purpose The built environment consists of a huge amount of infrastructure, such as roads and utilities. The objective of this paper is to assess the life cycle financial and environmental impact of road infrastructure in residential neighbourhoods and to analyse the relative contribution of road infrastructure in the total impact of neighbourhoods.Methods Various road sections are analysed based on an integrated life cycle approach, combining Life Cycle Costing and Life Cycle Assessment. To deal with complexity, a hierarchic assessment structure, using the principles of the "element method for cost control", is implemented. Four neighbourhood models with diverse built densities are compared to gain insight in the relative impact of road infrastructure in neighbourhoods. ResultsThe results reveal important financial and environmental impact differences between the road sections analysed. Main contributors to the life cycle financial and environmental impact are the surface layer and electrical and piped services. The contribution of road infrastructure to the total neighbourhood impact, ranging from 2% to 9% of the total cost, is relatively limited, compared to buildings, but not negligible in low built density neighbourhoods.Conclusions and recommendations Good spatial planning of the neighbourhood is recommended to reduce the amount of road infrastructure and the related financial and environmental impact. The priority should be to design denser neighbourhood layouts, before decreasing the financial and environmental impact of the road sections.

Due to the growing population, the revived trend of living in urban areas and the scarcity of building plots, the idea of vertically extending existing residential buildings is gaining popularity in Belgium. Timber frame constructions are appropriate due to their light weight and lack of point loads. This article aims to assess (1) the potential environmental impact reduction of light-weight timber frame constructions for rooftop extensions by changing composition and dimensions and (2) the effect of biogenic carbon. Timber frame walls and roofs are analyzed based on the life-cycle assessment method. Starting from the current building practice in Flanders, various parameters are assessed. The effect of using I-joists instead of solid studs, of adjusting the center-to-center distance between the studs and of changing materials for different layers is analyzed. The results showed a limited environmental impact reduction of using I-joist instead of solid studs and of adjusting the center-to-center distance. Changing the composition of the walls and roofs in terms of materials can lead to a total life-cycle environmental reduction of 22 % and 14 %, respectively. If biogenic carbon accounting is integrated in the assessment method, based on the ILCD method, the total life-cycle environmental impact is reduced by up to 35 % and can lead to significant differences in the preferred choice of timber frame composition. Highlights Influence of changing construction and material parameters is assessed using LCA  Environmental impact can be reduced by up to 22 % by changing wall parameters  Environmental impact can be reduced by up to 14 % by changing roof composition

No abstract

No abstract