The redevelopment of the HVB Tower is an uncommon architectural challenge, as the project involves the renovation of an urban landmark. HVB Tower is a sculpture, a one-of-a-kind building whose design and appearance are still fascinating to this day. The 'dematerialization' effect of the building originally intended by the architects Betz in the design of the façade is part of its uniqueness. From an urban development point of view, HVB Tower – as can be easily seen on panoramic photos – is a formative feature in the Munich skyline.
Protection of historic buildings
Since its completion and inauguration in 1981, the Tower has undergone a number of transformations: small and large renovations were made, of which the largest was probably the conversion of the retail centre in the north low-rise building, which took two years from 1998 to 2000. The complete renovation of the casino and the south low-rise building in 2001 was the last major action before the building was listed as a protected momument in 2006.
So for the architectural firm HENN, the starting situation in the renovation of the tower was a building whose interior, unlike the external façade, was no longer in the original condition.
The challenge now consisted of analysing which areas of the building’s interior are worthy of preserving for the purposes of historic conservation. The results showed that due to the earlier conversions hardly any original material from the time it was erected was left and consequently there was greater room for reinterpretation. This freedom is being used to do justice to the high aesthetic standards of the building, with a subtle interior design – developed from the building shell and its design principles – that also meets the requirements for its future use as the seat of the Executive Board.
Meanwhile, the historic preservation requirements for the façade were clearly identified from the outset: the renovation would have to revolve around retaining all the design and visual characteristics of the façade shell. The real challenge in the planning process was to reconcile this with the new, modern requirements the façade has to meet.
Right from the start – practically since HVB Immobilien AG placed the order and while drafting the first design concepts – HENN and the client/developer entered into an intensive dialogue with the conservation authorities and with Oliver Betz, the representative of the original architects. Only in this close dialogue was it possible to develop a building-specific and future-proof façade concept that guaranteed the functional and physical construction requirements of a modern skyscraper façade while keeping its appearance identical with the existing façade, and thereby considered the concerns of all stakeholders to the greatest possible extent.
Within this extensive project, the energy-efficient renovation of the façade is one of the most important measures because it is prerequisite to realising a modern climate control concept with maximum user comfort and convenience.
The sheet metal panels of the existing façade itself are professionally cleaned and reused for reasons of monument preservation as well as to minimise resource consumption. The supporting structure, insulation and glass panes are completely new.
Until now the façade consisted of single-shell elements with double glazing units, which are now being replaced with double-shell elements (box window design principle). The inner layer of the elements is triple glazed. Barely perceptible perforations in the façade elements allow outside air to enter the box window space and if necessary continue on inside as fresh air into the offices through openable windows.
In future the box windows will contain sun protection – another technical innovation in the construction of the façade. Protected from wind or weather conditions by the outer deflector pane, this sunscreen ensures a significant reduction in external heat loads, thereby enabling the building systems to be upgraded to a more future-proof status. The proposed heating-and-cooling ceilings represent an investment in a modern climate-control concept that is energy efficient as well as providing the best possible user comfort.
The sun protection also serves to protect the workstations from glare.
Along with the heritage authorities, the fire brigade and the local building committee have been close dialogue partners for all planners responsible for the project since planning began.
As HVB Tower is a skyscraper, its fire protection was designed in accordance with the high-rise directive and in consultation with the authorities. A fire protection concept was jointly developed – based on the existing supporting structure – that represents a significant improvement and ensures the [building’s] long-term operational safety.
The tower’s existing staircases will serve as pressure-vented safety stairwells in future. In the event of fire, fresh air would be blown into all four stairwells so that they remain free of smoke and enable a safe evacuation. During its integration into the planning the complexity of this system influenced the structuring of the entire building, because the excess pressure generated by the air blown in must escape in a controlled way again through the building shell.
In addition, among other things, a full sprinkling system and full-scale monitoring by a fire detection system will ensure maximum safety.
By optimising the internal structure of the floors for fire protection purposes, maximum flexibility in office space structure was achieved without compromising fire protection objectives, which follows the original design concept from when the building was erected as well as meeting today's needs and aspirations.
Interior design & layout
An appropriate quality of design and materials is critical to the future interior of the storeys.
Future, progress, timelessness, quality and design are the visual messages communicated to us by the building exterior. This claim must be clearly followed up on the inside of the building for everyone to see, thereby creating a unity between its outdoor and indoor spaces.
The spatial reinterpretation is based on the principles of the original design, which were ultra-modern in the 1970s: a flexible and future-oriented office space structure that is adaptable to changing office workflows. This was the original intent and is now being planned for as well. Both individual offices and multi-office landscapes are possible and, thanks to the shape of the building, the rooms are always well lit and have glorious views from this spectacular architectural monument and landmark of Munich.