Motivated by the understanding that planning and managing the service life of buildings can contribute to sustainability, cost reduction, and the safety of users and passers-by, this study aims to predict the service life of an unfinished and paralyzed reinforced concrete building. Its concreting began in 2013 and was halted in 2016 before the finishing and coating work was carried out. Since then, there has been no maintenance or return to work. The building is exposed to a maritime environment with heavy vehicle traffic, which can be classified as highly aggressive. The service life prediction methodology used is based on the factorial method proposed by ISO 15686-8/2008, which uses multiplicative factors applied from a base age for the project. The standard defines seven factors that show the degradation of structures: quality of components, level of design, execution of the work, internal environment, external environment, conditions of use, and level of maintenance. Methods defined by standards or based on references were used to determine each factor. Applying the proposed methodology, the results showed a reduction in building service life, mainly due to the degradation inspected on-site. It was found that the building under study has a service life of 35 years, below the expected minimum of 50 years. The main contribution of this study is to deepen the knowledge on methodology for estimating the service life of reinforced concrete buildings, helping professionals carry out building inspection reports.