Moisture Transfer through Facades Covered with Organic Binder Renders

• Main Authors: Carmen DICO, Henriette SZILAGYI, Cornelia BAERA
• Format: Article
• Language: English
• Published: National R&D Institute URBAN-INCERC, INCERC Bucharest Branch 2013-07-01
• Series: Constructii: Journal of Civil Engineering Research
• Subjects: Moisture transfer; Organic binder renders; Water absorption; Vapor permeability
• Online Access: http://constructii.incerc2004.ro/Archive/2013-1/Constructii_2013_Vol.14_No.1_ID2013140108.pdf

Year after year we witness the negative effect of water over buildings, caused by direct or indirect actions. This situation is obvious in case of old, historical building, subjected to this aggression for a long period of time, but new buildings are also affected. Moisture in building materials causes not only structural damage, but also reduces the thermal insulation capacity of building components.Materials like plasters or paints have been used historically for a long period of time, fulfilling two basics functions: Decoration and Protection. The most acute demands are made on exterior plasters, as they, besides being an important decorative element for the facade, must perform two different functions simultaneously: protect the substrate against weathering and moisture without sealing, providing it a certain ability to “breathe” (Heilen, 2005). In order to accomplish this aim, the first step is to understand the hygrothermal behavior of coating and substrate and define the fundamental principles of moisture transfer; According to Künzel’s Facade Protection Theory, two material properties play the most important role: Water absorption and Vapor permeability.In the context of recently adoption (2009) of the “harmonized” European standard EN 15824 – „Specifications for external renders and internal plasters based on organic binders”, this paper deals extensively with the interaction of the two mentioned above properties for the coating materials, covered by EN 15824.