The former historical telephone exchange was converted into an inspiring office building
In today’s Lehárgasse No. 7., hidden behind the magnificent 19th century facade lies an architectural treasure: a former telephone exchange for K. und K. Post- und Telegrafendirektion (postal and telegraphic administration) with two historic telegraph halls designed by the architect Eugen Fassbender. After spending the last decades in a deep sleep, the telegraph office under a preservation order was converted into a contemporary office building by BEHF Architects in coordination with the Federal Monuments Authority Austria (BDA).
Two halls with particularly high ceilings on the main floor represent the heart of this architectural project. The task was to connect both halls and create a new space for the headquarters of the real estate agency JP Immobilien.
The centre of the architectural concept are two minimalistic glass boxes that serve as work space and seem to be detached from the existing historical inventory, looking like large pieces of furniture: a room-in-room construction, which was placed into the opulent telegraph halls featuring stuccos restored true to original, and colourful wall paintings. The historical fabric remains unaffected and finally becomes visible after years of being hidden from the public. Therefore, the room itself is a great highlight.
In the glass boxes, there are office spaces and conference rooms. On their upper surface is a neutral, multi-purpose event area which can be used as an open-plan office, for instance. From there, bridges penetrate the listed walls and lead to service rooms that are available to everyone who works in the two main halls.
In order to make the glass boxes appear light, almost hovering, BEHF Architects chose a continuous flooring, while the glass surfaces were fitted with a fine mirror effect. By means of a screen-printing technique, an additional frosted layer was applied to the glass walls, whose pattern intensifies towards the top. This way, constructional parts are hidden, while the pedestal area stands out due to its open, transparent appearance.
The minimalistic and elegant design reappears in different other areas of the building: for example, the entire surface of the entrance portals leading to the elevator and to the offices is made of brass, while intarsias were installed on a terrazzo as floor designation. In addition, highly polished brass was fitted to the bottom view of the balconies facing the inner courtyard, so that the plants on the ground are being reflected.
Both the design concept and the lighting concept follow the principle of drawing attention to the historical substance as precisely as possible, while giving the room a functional or atmospheric effect as well. In doing so, the basic motif of blurring boundaries always prevails.