Hygrothermal and environmental performance of a perlite-based insulating plaster for the energy retrofit of buildings

The thermal conductivity values of the four plaster mixtures ranged from between 0.118 W/mK and 0.059 W/mK, thus demonstrating that the perlite concentration had a significant impact on the reduction of thermal conductivity and that the embodied energy of the applied material (5 cm thickness) decreased as the perlite content increased. Moreover, the results of the measurements on the demonstration building and the hygrothermal simulations have revealed that the thermal insulating plaster is able to reduce the U-value of the wall. However, an increase of 26-30% of the actual thermal conductivity should be considered when the material is exposed to real operating conditions.