The foundation of the circular economy in the construction sector is based on implementing the deconstruction and reuse of buildings, providing the potential for a closed loop of building materials within the supply chain. Mass timber buildings using large, prefabricated elements and certain types of reversible mechanical connections are deemed to have great potential for post end-of-life (EoL) options, including recycling and reuse. To fully characterize the benefits of reusing post-use mass timber in new construction projects, it is crucial to conceptualize a ‘grave-to-gate’ approach, including the complete analysis of post-EoL activities and impacts on the material’s second life. In this study, a comparative life cycle assessment (LCA) including different EoL and post-EoL options for a virtual reference mid-rise mass timber building in the Pacific Northwest (PNW) of the United States was conducted. Among four different deconstruction and reuse scenarios examined in this study, a case of nearly complete reconstruction of a mass timber building for the second service life used as an idealized reference established an optimistic limit for reduction of global warming potential (GWP) by 13-41% compared to the ‘demolish and landfill’ decision, depending on the scenario. The demolition and landfill scenario had the lowest net impact since the GWMP calculations accounted for the carbon storage benefits in the landfill in addition to the carbon stored in the building.