Green Building in Silver: Modernization of the HVB Tower in Munich

When a building becomes an historical monument 25 years after its completion, that speaks for its quality. This was the case for the headquarters of the HypoVereinsbank in 2006. Even the citizens of Munich, who are usually sceptical about skyscrapers, have become fond of the silver tower with its striking exterior support structure. This despite the fact that it is the first building to exceed the magic 99-metre limit set by the twin towers of the city’s Frauenkirche. The unconventional support structure, which is fixed via a type of gigantic pipe brackets on four exterior pylons, is enabled by its subconstruction. Munich’s subway system goes directly under the tower, and the building’s foundation must not touch the tunnel. Therefore, a central load-bearing core was not possible.  The huge supports accommodate elevators, utilities and the escape stairs. The office floors, which form an isosceles triangle, are not directly attached to the supports. Like stacked tablets of reinforced concrete, they rest on the technical floor located on the eleventh storey. This storey acts as a supersized cross-girder. The office levels below have been suspended from it.  On its north and south sides, the tower is flanked by two lower structures. Over the past three years, one of these has been updated along with the tower. Work on the north-facing structure is to begin over the next few weeks and should last until 2019.

Façade Refurbishment in Zipper Style Efficient use of space, economy, historical monument protection and sustainability: this is what Peter Weidenhöfer, CEO of HVB Immobilien, calls the four pillars of the refurbishment plans. A key aspect of lower energy consumption (50 % less for heat, 25 % less for electricity) was a change of façade. Two enormous cranes, mounted on the pylons, removed the storey-high elements from the building’s shell and replaced them with new, better-insulated façade components. This work proceeded upwards and ensured that no more than two or three storeys were exposed at any one time. Ultimately, the tower was never to appear as a naked skeleton in Munich’s cityscape. While the characteristic rounded metal panels have been cleaned and reused, the rest of the façade is completely new. Seen from outside, it looks the same as it did before the refurbishment, but is now significantly better insulated and has been fitted with casement windows whose interior wings can be tipped automatically. Between the two window levels, a sunshade has been added. Instead of the old sill convectors, the office storeys now have heating and cooling ceilings. These are warmed via district heating and chilled by a system connected to the groundwater. Working Environment 4.0   The homogeneous white-grey business look of the office storeys displays an astounding diversity of workspace configurations. Two rows of cubicles have been arranged along the windows; the middle of the space features a coworking area for group projects. The meeting rooms are located at the corners of the building. The working spaces are non-territorial, meaning that employees must deposit their belongings in lockers found in the foyer of each floor before they leave for the day. Each locker can be opened with the respective employee’s ID card. One small detail emphasizes the fact that HVB has taken a holistic approach to sustainability: all printing jobs end up on a waiting list and are actually printed only when and where employees let the desired printer scan their ID cards. In the three-storey foyer at the foot of the tower, there used to be a tree-like sculpture with triangular “leaves” of metal sheeting (George Rickey: “forty triangles in three sets”). The architects had this disassembled and replaced with a large-scale sculpture that develops from the building itself. Now, an acute-angled “crystal” of white mineral-based panels is arranged around the balustrade, guiding our gaze up to the atrium roof, which – not surprisingly – also consists of triangular glass elements.