Selection of an Optimized Maintenance Policy for Rendered Facades

Abstract

The maintenance of external facades’ claddings has been neglected over the years. The maintenance actions were limited to total replacement when the claddings showed a severe degradation condition. However, in the last years, this attitude started to change, but stakeholders faced two different approaches in performing maintenance activities. The first approach corresponds to the application of time-based maintenance policies, in which the maintenance activities are carried out periodically with predetermined schedules. In the second approach, condition-based maintenance policies are adopted, in which the degradation condition is assessed through regular monitoring and, posteriorly, the more adequate maintenance activities are defined. This study intends to compare these two maintenance policies and analyze whether there are advantages in implementing condition-based maintenance strategies in an economical and very common cladding solution. Therefore, the influence of the two maintenance policies on rendered facades is analyzed in terms of service life, maintenance costs, efficiency index, and number of replacements. A multiobjective optimization is performed to understand whether there is an optimal time interval for performing the inspections in condition-based methodologies. Based on these results, an equivalent time-based maintenance policy is developed. The periodicities for the maintenance activities recommended in the literature are constant regardless of the maintenance strategy adopted. Consequently, it is impossible to define an efficient plan for all maintenance strategies assuming the same time of intervention. In fact, the periodicities of the maintenance actions must be adjusted according to the maintenance strategy adopted. The comparison between both policies revealed small differences between maintenance costs, service life, and efficiency indices. However, in time-based maintenance policies, more interventions are always performed during the time horizon, increasing users’ disturbance and the risk of unplanned maintenance because coatings are not regularly monitored between inspections.