Hygrothermal performance of an internally insulated masonry wall: Experimentations without a vapour barrier in a historic Italian Palazzo

This paper presents the newly developed study, methodology and assessment of the hygrothermal performance of a historic building wall retrofitted with three different internal insulation technologies, without a vapour barrier. It aims at assessing any possible condensation problems at the most critical point of the tested stratigraphy (namely, in between the wall and the insulation material) and to limit the modification of the original hygrothermal behaviour of the original wall's materials with the addition of a vapour layer, as would commonly be used. This evaluation was performed through in situ measurements and dynamic software simulations. In situ data was used for calibrating the 2D simulation model conducted with Delphin software 6.0.20. Under the climatic conditions in Ferrara (Italy), the results of both the in-situ monitoring and simulation evidenced no risk of frost damage to the building's original wall. With regards to the risk of interstitial condensation, simulations showed no high risk even in the absence of a water vapour barrier. Additionally, the amount of water vapour collected during the winter season dried out during the spring/summer period.