Between Midnight and one o‘clock in the morning, the site is very well connected to the whole city: The last tram of many tram lines ends up at Tramdepot Elisabethenstrasse, right beside the site. This fact led to the idea to imagine the main space – neutrally described as Veranstaltungsraum in the programme – as a nightclub. Privy people take the last tram from all over the city to go clubbing at Katze. Similar to the existing building, the structure is elevated to keep the current qualities alive, such as the frequent use of the open ground floor by children and teens from the neighbourhood and the value of the building as a landmark.
During daytime, the building is inhabited by the teenagers of the youth centre in the first floor, musicians practising in the three uppermost floors and the radio broadcaster of GDS.FM. As the building stands on pillars, the ground floor is kept free as a flexible space, partly covered by the building, partly open to the sky, providing a minimum of infrastructure to permit a wide range of use during various times of day and seasons: mobile baskets, underfloor distributors for power and fresh water and a new, smooth asphalt inviting for skaters.
The building is has a circulation of two stairs and a lift. While the main staircase is part of the loggia and follows the rules of the building, the nightclub stair is a leftover of the perception of the building as something foreign debarked at the site. The Nightclub is divided by silver curtains in two different lengths, the full room height long curtain provide intimate corners while the shorter establish a main space by releasing from the outer shell. Important was to avoid views from outside into the nightclub. The rehearsal rooms work as simple boxes, which can be widely opened to the loggia to permit heavy transport. To change acoustic properties, every rehearsal room has the possibility to line the brickwork or to separate the room by curtains.
Construction wise, the building is planned as an exposed steel structure. To avoid cold bridges, every floor is insulated individually; while the high amount of insulation would be inefficient for a normal building it has his right to exist in a house for music as it helps to prevent sound transmission from floor to floor. For acoustic reasons the floors are lined with brickwork. As the exposed steel structure is an inopportune kind of construction and often tend to a very technical expression, the thesis was to design a facade which avoid this technical fetish without imposing an ornament. The result is a panel sheet facade sheet metal facade which can be partly opened or completely closed and establishes together with the structure, ventilation and structurally needed elements for the loggia composition. The structure is stiffened by concrete elements between the flanges of the floor beams and fixed pillars.The loggia works as a hanging structure, dependent on the primary structure of the building and supported by diagonals in the top floor. To reduce buckling length in the area of the club, pillars are separated between third and fourth floor.