Abstract
A broad outdoor weathering experimental study was conducted to gain better insight into whether for future building product authorization in Europe mortars and plasters could be classified as products without testing / products without further testing (WT/WFT). To cover a wide range of mineral building products for outdoor use, worst-case-formulations were created in cooperation with industry. In a three year outdoor weathering experiment elution tests of mortars and plasters for outdoor use were performed. Leaching results were recorded and evaluated. The concentration of dangerous compounds in the rainwater running down the test specimen is not suitable for assessing the environmental impact of weathered façade coatings because filtration by soil and dilution by other rain water is not considered. Also an existing evaluation scheme for the environmental impact of concrete in direct contact with groundwater cannot be applied. Under real conditions there is no direct correlation between substance concentration in the run-off water and the amount of substance released. It could be shown that elution of compounds of façade coatings under real conditions are in most cases below the prescriptive limits.