Stains in facades’ rendering – Diagnosis and maintenance techniques’ classification

Stains in rendered facades occur very frequently in recent buildings due to various causes (efflorescence, carbonation, corrosion, cracking, dirt deposition, biological colonization and others). Most of the stains are damaging. In an initial stage, these anomalies affect the aesthetics of the façade and, some types of stains, in conjunction with the presence of water, contribute to the physical degradation of the cladding. This paper presents a set of tables and correlation matrixes related with the different types of stains, their possible causes, diagnosis techniques and treatment techniques (in particular, cleaning techniques) aimed at removing the stains from the rendered facades.