Natural stone in ventilated façades: method for determining the appropriate moisture content for strength tests

The article discusses the effect of the assumptions about moisture content on the design of ventilated façades with porous natural stone cladding. Moisture is shown to impact cladding strength and condition its dimensions. For this reason the performance of such façades when exposed to water should be analyzed more fully than specified in EN standards. An example is given of how to conduct such an analysis, along with guidelines for choosing a moisture content value that correctly reflects the absorption levels attainable in such façades. This value is then used to determine panel mechanical strength. Application of the method to three sandstones from Northeastern Spain showed the utility of the type of analysis proposed.