For us, this project is as much about taking the opportunity to define the diffused limits of the Glacis more clearly – and to reposition the Karlskirche as an important component of the square – as it is about creating additional spaces for the Wien museum.
Our initial concern was to determine what kind of extension could best complement the existing museum. We felt that the present volume should continue to define the visual limits of the square as they are today. However, the program requirements stressed the need for additional, discrete exhibition spaces.
Consequently, our emergent idea was to configure an ensemble of independent additions – a novel aggregation – rather than proposing a single new volume. Our goal has been to find an architectural expression that could accommodate any of a range of as-yet-unforeseen activities that might occur in both the museum and the Karlsplatz square over future times.
Our proposed extension is thus an ensemble of four distinctive components: a colonnade facing the square housing all the active public functions; a trapezoid-shaped volume inserted into the colonnade – a key feature that introduces a visual distinction between old and new – a single-floor rooftop addition to host additional exhibition spaces; and a basement level volume accommodating further open display and service areas.
Our first step is to propose a rhythmic freestanding colonnade aligned along the Canovagasse, taking its design cue from an earlier museum proposal by Otto Wagner. This wedge-shaped volume is positioned diagonally in the existing museum forecourt, creating a new covered public space that functions independently of the museum, but which acts as a transition between it and the square.
The size and configuration of the colonnade are defined by a complex set of referential grids and alignments, designed to enhance the prominence of the Karlskirche over the square, and to integrate the museum with the neighboring Winterthur building. It operates as a neutral foreground, reflecting the architectures of the square’s different elements, and bringing together the different scales of its adjacent buildings.
The design of the colonnade allows the space to be used for semi-outdoor galleries, as well as for a range of other public activities. The roof follows the alignment of adjacent streets and creates visual lines that enhance the visual legibility of the Karlsplatz’s layout. It transforms the space, adapting to its surrounding buildings, but without altering their relationships with the square.
The colonnade’s façade maintains the structural rhythm of the existing museum building, but is expressed minimally on a simple grid of concrete and stone bearers, free from structural ambiguity: an ‘urban gesture’ that sets the tone for the desired continuity between the square’s established elements and our new additions. We extend the museum entrance into the colonnade, so visitors are routed through the covered space via a seamless ground level connection between square and museum that effortlessly massages away the one-meter height difference between the two.
The height of the existing museum is not aligned with the urban design guidelines applicable for Glacis buildings. Rather, the proposed rooftop extension adheres to the heights and building lines defined by adjacent buildings on the Karlsplatz. We also suggest reconfiguring the Winterthur building to fundamentally alter the way it opens onto the Karlsplatz, and how it relates to the museum ensemble.
Our design proposal retains the main architectural features of the existing Wien museum building – its peripheral façade and central courtyard – while reorganizing its various internal elements to meet the program’s requirements. Restricting the loadbearing elements to the peripheral and inner courtyard façades allows for column-free exhibition spaces. The exhibition galleries within the existing building will be renovated and reorganized as a series of contiguous rooms around an inner courtyard – most rectangular, some square – which do not need interstitial spaces or connecting corridors (so freeing up more display space).
The new rooftop volume above the main museum building creates a fresh exhibition area. Lit primarily from above, it is characterized by a lightness that offers a striking contrast against the solid mass of the existing building. The variety of rooms and galleries are reflected in the skylights’ different types and sizes, which are determined by the configurations of the contiguous exhibition volumes, and reveal broken and fragmented roof silhouettes.
The trapezoidal volume will house the cafeteria, the Vienna room and event spaces – all public functions that engage directly with the plaza and can be accessed independently outside museum hours. The reconfigured basement will accommodate an additional large gallery space for temporary exhibitions, as well as housing service functions.
In sum, the proposed extension ensemble does not aspire to transform the museum’s existing image: rather, it seeks to create a dialogue between familiarity and novelty, between old and new, creating an enveloping structure to engage with the endless progress of change at the Karlsplatz site.