Schloss Kuenburg, built in the end of the 16th century has proven its ability to change several times until today. The former residential building of the noble house of Kuenburg transformed into a building for educational and cultural activities after acquisition by the municipality of Tamsweg. An enlargement was planned to serve a greater amount of visitors. The topic of this master thesis is to create a concept for the refurbishment of the heritage protected building and to design a multifunctional event center. The aim of the refurbishment is to optimize the building in terms of energy and function according to the needs of the users. Furthermore the premises of the castle should be used to access the new extension and to be valued by this. The multifunctional new building shall meet the state of the art and is designed after acoustic principles for speech and music theatres. A vitreous corridor creates a symbiosis between the old and the new.