Existing buildings within an aggressive environment suffer deterioration of their making up materials. This deterioration, over the time, can lead the system to a loss of performance. When the loss of performance is greater than prescribed threshold values it is considered as a failure and the system passes from current service state to another one characterized by a lower level of performance. However, mainte- nance and/or rehabilitation can improve structural performance. Both these interventions can be defined as transition stages and modeled as Markovian processes. In this paper applying a Markovian approach associated to a Monte Carlo simulation, the maintenance planning within decision-making...