The effect of temperature, humidity and mechanical properties on crack formation on external thin plasters of ETICS

Abstract

External Thermal Insulation Composite Systems (ETICS) are widely used in the northern hemisphere in retrofitted and new external walls. The outer layer of ETICS is usually a thin layer of plaster. The effects of temperature and humidity on the hygrothermal behaviour and mechanical properties of thin plasters have been quantified by conducting several experiments to determine the possibility of crack formation. Combinations of plasters using four types of binders are tested: mineral, polymer, silicate and silicone. Plasters are tested as four systems consisting of a base coat, a glass-fibre reinforcement mesh and a finishing coat. Sorption curves of the plaster systems are determined to gather data for numerical simulations. The coefficients of thermal and hygroscopic expansion are determined. The modulus of elasticity and tensile strength of four different plasters are measured to allow the calculation of crack formation in ETICS and suggest the distances between the deformation joints. The method demonstrated in this paper makes it possible to calculate the crack formation caused by the temperature and moisture shrinkage in the thin exterior plaster of ETICS.

Hygrothermal Performance of Thick PCM Mortar behind PV Panels in Energy-Activated ETICS Facades

“…For autoclaved aerated concrete (AAC), adhesive mortar, EPS and mineral wool, materials from the Delphin database were used, with some minor changes according to local material manufacturers' data sheets. The hygrothermal properties of the particular facade plaster system used in the experiment were previously measured at the Tallinn University of Technology [33]. Properties of the PCM composite mortar (made from PCM granules and cement filling) were measured both at Tallinn University of Technology and Lodz University of Technology [16].…”

On site measurement and hygrothermal modelling of degraded ETICS facade with EPS and mineral wool fire breaks

“…Previous studies have measured thermal expansion coefficients of different facade plaster systems applied to different insulation materials. It appeared that there is not much difference between the thermal expansion coefficient of the plaster system applied to the EPS and the same system applied to the MW [9]. However, when the plaster system detaches from the substrate, the thermal expansion coefficient can increase by up to two times [9].…”