This article describes an approach developed to estimate the environmental external costs of the Belgian building sector. Several existing methods and related data sets for determining the monetary value of environmental impacts were reviewed and compared in light of their relevance to an impact assessment of the construction sector. This study concludes that the methods available consider different impacts and differ substantially in monetary values for identical impacts. A harmonized and transparent method is recommended to improve the feasibility and acceptance of internalizing external costs; agreement on the impacts to be assessed and their external costs based on current insights is important. Here, a new method is proposed for a life cycle impact assessment-based valuation of environmental external costs for application to the Belgian building sector. To enable a comprehensive assessment, it became clear that solely considering “key” pollutants is insufficient.
Although this article focuses on the development and not on the implementation of the method proposed, implementation revealed that the life cycle environmental external cost of new buildings (meeting current insulation standards or better) is relatively small compared to the life cycle financial cost.