Impact of the imperfection of thermal insulation on structural changes of thin-layer façade claddings in ETICS

The article presents research studies carried out on ETICS in the accelerated aging chamber, with gaps used as the predetermined imperfections. Based on the conducted research, Authors defined mineralogical changes taking place in plasters and porosimetry tests illustrating the changes resulting from the imperfections introduced to the system. Based on the research, it was found that over time, for mineral plasters, open porosity increases much more than for polymer plasters. During the aging process in acrylic plasters there is a strong rearrangement of micropores towards mesopores. In places of imperfection in the polystyrene layer there are higher amounts of carbonate salts compared to places outside of gaps. This effect is clearly visible in mineral plaster, where CaCO₃ calcite salts are formed, and in acrylic plaster salts of CaMg (CO₃)₂ dolomite. Features such as water vapor diffusion coefficient, water absorption, interlayer adhesion, and other impact resistance were also determined. Discontinuities in the insulation material already 2 mm wide cause an increase in the vapor-permeability of the entire system, creating the so-called diffusion bridges. In terms of system durability, the weakest element is the plaster layer and the contact zone with the primer. Of the tested systems, the best durability was demonstrated by the variant in which a primer based on styrene acrylic resin was used as the bonding layer.