Limit States and Service Life of Cement Renders on Façades

Abstract

The research presented in this paper is related to the durability of cement renders on facades, based on fieldwork data relative to the condition and extent of degradation of 100 facades of residential buildings in Portugal. Deterioration paths are obtained for staining, cracking, and detachment that show the loss of performance of the facade over time until a critical minimum acceptance level is reached, which is considered an estimated durability limit. These degradation patterns are analyzed individually to confirm whether any of three types of defects can effectively be considered limit states for the durability of cement renders on facades. The combined effect of all the defects that occur is also modeled as a single degradation path, and the expected service life is quantified. The results confirm that detachment constitutes a limit state of cement-rendered facades because it directly affects the physical durability of renders. Staining and cracking alone do not generally tend to signal the end of t...