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The Vienna Museum – a fusion of old and new

Sustainability and preserving the historic character were key priorities for the renovation of the Vienna Museum on Karlsplatz. An additional floor that appears to float above the old building has also almost doubled the museum’s available floor space. SageGlass electrochromic glass helps keep the indoor climate in the museum spaces stable. The smart glass helps prevent excessive light and heat.

The Vienna Museum on Karlsplatz is one of the most-visited museums in the Austrian capital. The renovation and expansion were intended to preserve the existing building structure and create a modern addition to the infrastructure. The project aimed to meet the historic exhibits’ complex conservation requirements while satisfying the need for sustainability and energy efficiency.

Fassade des Wien Museums, man sieht die intelligente Verglasung SageGlass sowie die Erweiterung des Gebäudes.
Photo Credit
Photo by ©Christine Koblitz
The Vienna Museum on the city’s Karlsplatz square has undergone extensive renovation and expansion. The new architectural design is an innovative blend of elements old and new. The new focal point is the concrete cube above the existing building, which almost doubles the exhibition space. ©Christine Koblitz

Vertical expansion

In the competition held for the renovation in 2015, Ferdinand Ĉertov and Winkler + Ruck Architekten secured the project with the concept of a vertical expansion. A concrete block “floating” above the existing building would supply the extra space required. The architectural pièce de résistance: the building’s old and new elements would be kept structurally separate. 

The new addition is anchored deep in the museum’s former atrium without affecting the existing building. To achieve this, a new foundation was laid in the atrium, consisting of a concrete slab, approximately 13 feet/ 4 m thick, on 40 bored piles, approximately 130 feet/ 40 m in length. A joint, nearly four inches wide, ensures that both parts of the building can vibrate wholly independently of each other in an earthquake.

Old and new come together in the new space to create a cohesive whole. The interface is represented by a transparent glazed terrace level complete with multifunctional spaces for events and workshops. Extraordinary views of Karlsplatz and the Karlskirche can be enjoyed from the freely accessible viewing platform and café.

Blick aus dem Inneren des Museums. Die intelligente Verglasung ist getönt.
Photo Credit
Photo by ©Christian Scheidegger
The all-glass pavilion expands the entrance area on Karlsplatz and acts as a welcoming gesture in the otherwise closed-looking old building. Together with the new plaza outside the museum, the pavilion helps anchor the institution in the local environment. ©Christian Scheidegger

New space to enjoy the museum experience

A new glazed pavilion outside the entrance area on Karlsplatz serves as an extended foyer and creates a segue between indoors and outdoors. Together with the new plaza outside the museum, the pavilion anchors the institution in the local environment. The museum’s new crown jewel, however, is the new central hall in the former atrium. Over 25 m high, it features a floating staircase with no visible supports. 

The original museum built by Oswald Haerdtl in 1959 has expanded its available floor space from approximately 6 900 m² to almost 12 000 m². The newly created exhibition spaces allow the permanent exhibition to be presented in chronological order and create more room for temporary exhibitions.

Blick von der Außenseite des Gebäudes. Das Gebäude ist weiß und grau. Die linke Seite ist vollständig verglast.
Photo Credit
Photo by ©Lisa Rastl
The design of the existing facade was based on Oswald Haerdtl’s original plans using different types of natural stone. Limestone and marble give it a unique texture. The concrete facade obtained its fine structure through special formwork and finishing by hand. © Lisa Rastl

Textured facades

The facades of the existing building date back to the original 1950s design concept by Oswald Haerdtl. They feature natural stone cladding consisting of different limestone and marble surfaces, and give the facade and brass-colored window frames a high-end texture.

For the facade on the new floating level, concrete specialists used special formwork and careful finishing to create fine lines running up and down the exposed concrete at irregular intervals. The edges of the vertical grooves were hand-cut to create the desired raw effect and natural shadow play.

Blick aus dem Inneren des Gebäudes in einen Besprechungsraum. Die SageGlass-Verglasung ist getönt.
Photo Credit
Photo by ©Lisa Rastl
The glass facade in the interstitial level, like all other window openings and glazed fittings in the Vienna Museum, is equipped with SageGlass. The electrochromic glazing regulates heat influx from sunlight and helps fulfill museum spaces’ exacting climatic requirements while achieving greater energy efficiency. © Lisa Rastl

Smart glass

The façade upgrade coupled with the use of regenerative energy for heating and cooling means the Vienna Museum on Karlsplatz covers almost all of its own energy needs. Extensive air conditioning is usually required for the purposes of conserving museum exhibits. In collaboration with restoration experts, building managers and planning specialists, opportunities were identified to reduce energy consumption while ensuring a stable indoor climate. Accordingly, the building was divided into three structurally separate and functionally independent climate zones, each with different requirements. 

The planners and client selected SageGlass Classic in all glazed areas separating the interior from the exterior. The smart glass maximizes daylight with minimal heat gain. These measures helped to significantly reduce the amount of energy consumed for lighting and air conditioning in the Vienna Museum.


Project information

  • Project: Vienna Museum
  • Location: Karlsplatz 8, 1040 Vienna, Austria
  • Client: Vienna City Museums
  • Architecture: ARGE Ĉertov, Winkler + Ruck
  • Structural engineering: Bollinger + Grohmann
  • General contractor: ARGE PORR, Ortner, Elin
  • Completed: 2023
  • Product: SageGlass Classic, SageGlass Symphony control system
  • Certification: Austrian Ecolabel


About SageGlass

SageGlass helps create low-carbon buildings that enhance occupant wellness by delivering the world’s best smart windows. Our electrochromic glass tints and clears automatically, optimizing both light and thermal comfort in a space - no need for blinds or shades. With SageGlass smart windows, your buildings can feature a lot of windows, without compromising on energy efficiency and performance. 

As the global leader in smart window technology, SageGlass has partnered with building owners, developers and architects on over 1,500 installations worldwide. Owned by Saint-Gobain, the world leader in light and sustainable construction, SageGlass is part of a group with over 350 years of building science and glass experience. 

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About Saint-Gobain

Worldwide leader in light and sustainable construction, Saint-Gobain designs, manufactures, and distributes materials and services for the construction and industrial markets. Its integrated solutions for the renovation of public and private buildings, light construction, and the decarbonization of construction and industry are developed through a continuous innovation process and provide sustainability and performance. The group's commitment is guided by its purpose, "MAKING THE WORLD A BETTER HOME."

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