The seat of the local PZKO group Třinec – Staré Město is located on the second floor of the townhouse in the center of Třinec. For the group's needs, a four-room flat was rebuilt. Nowadays, the group uses only a part of the space; however, especially since 2020, they're rented by a Polish artistic ensemble Ars Muzica which resides there and also has an extensive musical library. The flat's reconstruction to fit the group's needs took place 15 years ago. The space includes a main hall for 40 people, created by joining two adjacent rooms, a kitchen, two more rooms, a hallway, and a bathroom. Today, it is also a place for rehearsals of the Canticum Novum choir. Additionally, the group also replaced the windows, the gas heating, and the water main. The Ars Muzica ensemble bought new wardrobes, lighting, and musical instrument after the building's structural stability was checked.