Performance Assessment of Mortar Facades: The Role of Finishing Types in Rendering Systems

This study evaluates the influence of the type of finishing, i.e. paint or ceramic tile, on the performance of rendered facades, through hygrothermal simulation and tensile bond strength tests. The research combines computer simulations with experimental data obtained from buildings located in Brasília, allowing for the observation of how different types of finishing affect the physical and mechanical behavior of mortar exposed to climate variations. The results show that the system with ceramic tile finish presents better thermal and hygroscopic performance, with lower temperature amplitude, smaller variation in relative humidity, and lower accumulated moisture content over time. These factors are directly related to better results in the bond strength tests, validating the role of ceramic finish as an effective protective layer for the mortar. In contrast, the system with paint showed greater vulnerability to environmental fluctuations and lower bond strength performance. The results highlight the critical role of surface finishing in the durability of rendered façades. It is therefore recommended that, in technical inspections, the mortar and the surface finishing be evaluated independently, especially in multi-layer systems. This research contributes to the refinement of technical and regulatory criteria for selecting and evaluating facade rendering systems.