External thermal insulation composite systems (ETICS) combined with cross laminated timber (CLT) reveal useful exterior wall constructions, which meet the requirements for sustainability, serviceability and durability of modern buildings efficiently. Associated thermal insulation and moisture protection requirements are essential design criteria to be considered in the planning process. In light of the European legal regulation concerning ETICS, our paper deals with the hygrothermal behavior of an existing exterior wall construction in solid timber construction with ETICS, experimentally determined by means of long-term monitoring situated in the residential project "_massive_living" (Graz, AT). Based on obtained data of temperature and rel. humidity for a period of two years, we not only evaluated building physics aspects concerning the suitability of the structure, but also derived the time depending course of the essential parameter "moisture content" for selected layers of the CLT element. In addition, corresponding data is compared with results gained from a hygrothermal simulation. Further investigation then was carried out determining the hygrical impact on the timber component by changing insulation material. Therefore, the hygrothermal behavior of commonly applied ETICS in combination with CLT as base material was simulated. Finally, resulting bandwidths of moisture content in dependence of the applied ETICS are shown and discussed.