RATAPLAN - Architektur ZT GmbH developed an innovative office building from a historic, demolished building at Andreasgasse 9, located in the heart of a conservation zone bordering the vibrant Mariahilfer Straße, through a new construction, renovation, and attic extension project. This innovative office building is dedicated to the theme of diverse social and design interaction. Combining architectural heritage with the latest requirements, the building now serves both inside and out as a positive example of comprehensive revitalization with contemporary office spaces. Nearly invisible new constructions, renovations, and extensions, appropriate to the pre-Wilhelminian ensemble, harmonize effortlessly with the historic façade from the past, and even inside, traces of earlier times are exposed rather than concealed. The concentrated office layout in the central zones – complemented by plantings and galleries – interacts with the needs of the users across the floors. The concept encompasses the façade, materials, and color scheme and fulfills the brief of expanding the neighboring Sozialbau AG headquarters.