Comparison of moisture buffering properties of plasters in full scale simulations and laboratory testing

Traditional and Modern Plasters for Built Heritage: Suitability and Contribution for Passive Relative Humidity Regulation

“…According to Roels et al [61], for a gypsum plaster, the thickness involved in the mechanism of moisture buffering is approximately 33 mm, and when thinner samples are tested, the MBV drops. Thus, considering that the results from Cascione et al [42] and the present study were both from specimens of about 20 mm thickness, it was expected that their thicknesses were completely involved in moisture buffering, and samples showed a different percentage of the potential response of each plaster. Nevertheless, there was no experimental proof in this study that a thicker G sample would respond with a higher MBV.…”

“…The possibility of introducing uncertainties in measurements was higher for smaller specimens, thus the number of specimens was increased from three to five, and a comparison with previous studies was run to confirm the accuracy of the results. Hence, Table 5 reports values of WVP and resistance factor determined by dry cup from the literature [40][41][42][43][44][45][46][47][48][49][50]. For clayand air-lime-based plasters, the consistent difference between the dry and wet methods has previously been shown by some authors [43,[45][46][47], with values of resistance factor determined by dry cup two times higher than by wet cup, but no evidence of this difference was found for cement mortars.…”

“…The MBV found for CL50_G50, 1.03 g/(m 2 %RH), was consistently higher than the one found by Ramos et al [9], while for G (0.61 g/(m 2 %RH)), the values were closer. Cascione et al [42] tested clay, light-weight gypsum, and NHL3.5 plasters. The tested clay was kaolinitic; the mortar had a 20% mass of water, the binder:aggregate ratio of the NHL plaster was 1.2:5, and the hemihydrate gypsum mortar had a 30% mass of water.…”

“…The values for clay and NHL were slightly higher than those obtained in the present study (1.49 and 0.80 g/(m 2 %RH), respectively), but the gypsum was almost three times higher. An unknown complete composition of the light-weight gypsum tested by Cascione [42] may explain the different response of two gypsum-based coatings. According to Roels et al [61], for a gypsum plaster, the thickness involved in the mechanism of moisture buffering is approximately 33 mm, and when thinner samples are tested, the MBV drops.…”

Moisture decay in buildings and the impact of weather

“…There are multiple parameters to consider when considering the moisture balance in buildings, including infiltration, ventilation, moisture buffering and weather conditions [1]. As Kraniotis et al [2] demonstrated, moisture buffering is influenced by air leakages, as help finishing materials to dry faster.…”