The HVB Tower in Arabellapark, Munich, also known as the Hypo-Hochhaus, is one of the city’s characteristic buildings from the late 1970s and early ‘80s. It is one of the Bavarian capital’s defining landmarks, or as the general curator of the Bavarian State Office for Monument Conservation says: "The Hypo-Hochhaus shapes the Munich skyline. Anyone who sees it knows they are in Munich." At the same time, skyscrapers are a very sensitive issue in Munich. For once, however, the current debate is not about the height, but about the renovation of the114-metre tall building building, which is taller than the Frauenkirche.
The Munich architectural firm Betz originally designed the building, and now serves as a consultant to the renovation project. This will ensure the preservation of the external characteristics of the high-rise, which was listed in 2006, and the subsequently constructed low-rise building. Henn Architekten is responsible for the planning and construction management, with Drees & Sommer managing the project. The building’s control systems, lighting, heating and air conditioning are being completely renovated and there is a new technical supply concept. The tower’s façade is to be reconditioned by the end of 2015, with all renovation measures for the high-rise and adjacent low-rise building to be completed in two phases by 2019. A total investment of around 250 million euros is currently estimated for the measures.
HVB Immobilien AG is lead-managing the project. In the interview, HVB Immobilien CEO Peter Weidenhöfer reveals details about the skyscraper’s complete refurbishment, and explains how the issue of the listed façade will be handled.
Mr. Weidenhöfer, what is the primary objective of the renovation?
On our part, there is no single overriding objective – the issues of space efficiency, cost effectiveness, the protection of historic buildings and sustainability are all to be addressed simultaneously. Besides improving efficiency, we’re also focusing on reducing CO2. We are taking a holistic approach in our planning, so we don’t want to give priority to the issue of sustainability or green building certification over convenience and monument conservation, or vice versa. Nor should efficiency or – to put it bluntly – the aim of accommodating as many employees as possible in the given space, be the guiding principle. Rather, we are striving to create a high-quality work environment that is in harmony with the other objectives, in order to ensure the building’s overall flexible usability and long-term operational reliability.
Will there be a new office concept as part of the redevelopment, and what it will look like?
The former interior layout no longer meets present and future requirements, and the internal heat loads have changed due to the IT equipment. So the floor space will be used more efficiently in future, and will be adapted to the requirements of modern communications technology. We’re already testing the innovative 'smart working' office concept at one of our Tucherpark buildings in Munich, and will include the experience gained from this pilot project in the new concept.
What is the structure of the new façade?
The current façade is a single shell, and the windows cannot be opened. After the renovation, a double-skin façade will offer the option of natural ventilation. The inner windows will be tilt-able.
The tilt mechanism is supported by a motor, so that the windows can be individually opened as well as centrally controlled.
For design reasons, the outer shell will look almost identical to the original and therefore no natural ventilation will be all but invisible on the outside, so as to comply with the monument conservation requirements. As this is not a full-screen glass façade, the air adjacent to the areas of the currently closed plates can be sucked in through small holes that are barely noticeable from a distance, and there is no significant visual impairment since the façade is structured and scaly anyway. The closed silvery panels and reflective windows will continue to generate interesting light situations especially in the evening, and the building will take on the colour of the sky. The space between the façades will not be accessible, so that no interior space is lost. Moreover, the double skin must be developed towards the inside, as an exterior development is not possible for monument conservation reasons.
The connections for the ventilation and cooling ceiling result from the inner form and the technical data of the facade. What is certain is that parts of the old facade can be reused in as far as it is economically feasible, with certain panels able to be reused 1:1 after cleaning. We won’t be able to repurpose the glass and the frames, but it may be possible to recycle some of them.
What design and technology are you using for protection from sunlight?Aside from the monument conservation-related considerations, the venetian blinds- system will not be on the outside due to the high wind speeds around the tall building. In addition, we don’t want the heat to reach the inside of the building to begin with. The sun protection will be located inside the double façade. In simulations, the gaps between the two panes and the ventilation cross sections were reviewed and mock-ups were prepared.
Will the building be certified and, if so, what will be its certification?
The HVB-Tower will get a LEED certification. We expect to score very high in the awards ranking, however this is not a dominant objective in the project. As I mentioned earlier, sustainability should be balanced with other criteria such as cost effectiveness, efficiency and monument conservation.
Interview: Melanie Meinig, industrieBAU