The circular building strategy has been put forward as an important part of the solution to mitigate the huge environmental impact of the building sector. Despite this important role, the current practical implementation of the circular building strategy stays limited to a few pilot projects. The relevance and the principles of the circular building strategy have clearly been stated, yet due to the large uncertainties about actual reuse or end-of-life treatment the actual gains of circular building solutions remain unclear. A method to quantify the impact of circular building solutions, necessary to convince the individual building actor, is lacking. Currently there are no LCA or LCC studies that are able to quantify the full impact of circular building solutions (module A to D). This is due to the large amount of possible scenarios (adaptions, reuse, high-quality recycling,…) during and at the end of life that need to be taken into account. To fill this gap this research aims to develop a comprehensive probabilistic LCA and LCC methodology that will be able to quantify the environmental and financial impact of a broad range of circular building solutions. This methodology will make it possible to objectively assess the actual benefits of circular building solutions and to draw up guidelines for designers, manufacturers, policymakers,…