MONITORING THE DAMAGE OF EXTERIOR RENDERS CAUSED BY THE ENVIRONMENT

Three renders commonly used in the Czech Republic on the exterior side of building envelopes are exposed for 2 years to the environmental conditions of the city of Prague. The effect of external environment on their possible damage is monitored using the measurement of a variety of material properties in selected time intervals. The experimental results do not show any significant deterioration of most parameters during the 2-year investigation period. The open porosity is found to decrease with time due to the continuing hardening processes. The mechanical properties are thus improved after 1 year of exposition and only little worsened after the second year. The changes in the pore structure also result in deceleration of waterand water-vapor transport and a slight increase of thermal conductivity. The obtained results will serve as reference data for finding a correlation between the accelerated laboratory tests and the behavior of analyzed materials in real building structures.

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