The former hardware factory Grünwald, established in 1907 and smoothly transformed into a design furniture wholesaler by Matthäus Jiszda in 1981, had already attracted Friedrich Achleitner’s attention, who included it in his guide “Austrian Architecture in the 20th Century”. The spacious structure with the load-bearing middle wall also appealed to Helmut Dietrich and Much Untertrifaller on their search for a suitable location for a Vienna branch office. The existing use resources were realized in the shape of a two-storey construction featuring residential units. The branch of the Vienna Architecture Centre is housed in the basement.

In its organizational logic, the newly designed architecture office by Dietrich I Untertrifaller resembles the headquarters in Bregenz. Historical elements of the original structure create a particular atmosphere that benefits from the interplay with sparingly installed contemporary elements. With regard to the apartments on the former flat roof, which are set back from the façade, it had to be taken into account that the inner section - apart from the middle wall and the air shaft wall - did not allow for any vertical load transfer. A system of cross-laminated timber beams, plates and slabs, to a certain extent statically functional in the spatial context, transfers the load and at the same time allows for remarkable architectural effects. Three strong, cross-laminated timber plates stand on both sides of the two frontal fireproof walls, as well as in the middle between them, orthogonal to the middle and air shaft wall. They support the two top longitudinal beams from which the roof of the upper storey is suspended. This allowed for designing the west side of both living spaces as a floor-to-ceiling glass wall with sliding doors, free of any supports. Another longitudinal beam is hidden underneath the continuous skylights, which, together with the cross-laminated timber slabs of the lower ceiling and the L-blocks of the room and adjoining room walls in the lower storey, support part of the load, while the remaining load is transferred onto the middle wall via strong steel sections that balance on said wall. After completion of the expansion, the complex load-bearing structure was fully absorbed by the functional floor plan and spacious window walls made any mental and construction efforts disappear into oblivion.