The Baumgarten-Bau () in Karlsruhe serves as the official seat of the Federal Constitutional Court. Built from 1965 to 1969 in the Botanical Garden of Schlossgarten, this building complex was originally composed of five pavilion-like structures with flat roofs, arranged around a long connecting corridor. Architect created the original plans. The total floor area of the Baumgarten-Bau is approximately 16,000 square meters. The individual components of the building differ in height and have only a few stories. The glass and steel facade of the building gives it a plain and sober aesthetic and is attributed to the Modernist style.
The Baumgarten-Bau became the official residence of the court in May 1969, replacing the Prinz-Max-Palais, which served as the official residence between 1951 and 1969 until it became inadequate for the growing need for space. The ensemble of buildings is designated as a cultural monument of special significance. From 2005 to 2007, an extension was added to the complex in the southwest, expanding it from five to six buildings. During extensive renovation work from 2011 to 2014, the Federal Constitutional Court temporarily relocated its official seat to the Oststadt district of Karlsruhe. In 2021, around 260 people were working in this building.
History Predecessor building
The Federal Constitutional Court initially had its first official residence in the Prinz-Max-Palais from 1951 to 1969. This city villa, dating back to the 1880s and designed by architect Josef Durm in the Wilhelminian style, is located in Karlsruhe's inner-city west near Europaplatz, about half a kilometer southwest of the current seat of the Federal Constitutional Court. The decision to establish the seat of the Federal Constitutional Court in Karlsruhe was made in December 1950, despite strong protests from Berlin. The Prinz-Max-Palais, which had been damaged during World War II, was subsequently rebuilt and adapted to meet the court's requirements. On September 28, 1951, a ceremony attended by the President of Germany Theodor Heuss and Federal Chancellor Konrad Adenauer marked the official move of the Federal Constitutional Court to the new premises. However, it became apparent that the Palais was insufficient in terms of space; the justices often had to share rooms with colleagues and staff, and for larger sessions, the court had to relocate to other halls in the city. As early as 1959, Gebhard Müller, who was the President of the Federal Constitutional Court at the time, expressed the need for a new building. There were considerations to move the Constitutional Court's seat to Munich or to relocate it to the nearby castle. The city of Karlsruhe wanted to prevent both and launched an architectural design competition in 1960.
Location search The Court Theatre, which had been destroyed during World War II, was selected as the location for the new Federal Constitutional Court building. This theater had been originally designed by architect Heinrich Hübsch. In September, architect Paul Baumgarten presented three out of the five initial design proposals for the building complex, which would consist of pavilion-like structures. The design was characterized by its sober and objective style, deliberately departing from the architectural traditions of court buildings from the 19th and 20th centuries. This approach aimed to ensure that the building complex would not disrupt the overall urban concept of Schlossplatz. To achieve this, the complex was built on the same level as the surrounding area instead of rising in height. Paul Baumgarten took inspiration from the German contribution to the 1958 Brussels World's Fair, designed by architects Egon Eiermann and Sep Ruf. Their transparent glass and steel architecture served as a structural model for Baumgarten's design.
During this period, there were considerations within the population and the administration to rebuild the Court Theatre. Paul Baumgarten also considered a possible new building as an architect and won the architectural competition for it. With the decision in favor of the new Federal Constitutional Court building, the plans to reconstruct the Court Theatre were ultimately abandoned. The demolition of the wartime ruins of the Court Theatre, although controversial, took place in 1964/1965.
Construction and use
In February 1965, construction work began on the ensemble of buildings in Karlsruhe's palace district. The topping-out ceremony took place in October 1966, and the official residence was handed over on May 6, 1969.Transparenz und Würde – Das Bundesverfassungsgericht und seine Architektur, pp. 166. The project cost almost , which, adjusted for purchasing power, equals approximately in 2023.
The construction period of the Baumgarten-bau coincided with the hosting of the 1967 Federal Garden Show () in Karlsruhe. Landscape architect Walter Rossow developed a green path for pedestrians from Karlsruhe's main railway station through the listed Stadtgarten to the Schlosspark. The green and open spaces around the Baumgarten building were designed to align with this concept and connect to the adjacent Schlosspark.
On the evening of March 4, 1975, there was an attack on the Federal Constitutional Court. An explosive charge was attached to a pillar of the justices' building, causing significant damage to a large window pane. However, nobody was injured. The investigation revealed that the explosive charge, due to its casing, could not have caused extensive destruction and had not been professionally made. Later, a radical feminist terrorist organization called the Red Zora claimed responsibility for the attack in a letter to the news magazine Der Spiegel. They had attacked to protest the Federal Constitutional Court's ruling, which had declared the reform of Section 218 null and void just a week earlier. Despite the letters of confession, the perpetrators were never apprehended.
Starting in 1982, the Federal Constitutional Court rented additional premises in the northwest wing of Karlsruhe Palace due to the growing need for space. An underground passageway connects the Baumgarten complex to these rooms. The former dining casino was converted into additional office space between 1995 and 1997. In 2000, seven more offices were added to the library's basement. In 2001, 13 additional rooms were allocated to the justices' building in the basement.
Supplementary building In a competition in 2002, the architect was finally chosen to design the extension. Over two hundred architects took part in the competition. The challenge for the design was to avoid causing any harm to the existing building complex or the Botanical Garden. During the competition phase, a citizens' initiative voiced concerns about the winning design, as it did not adequately consider the protection of the Botanic Garden. Eventually, this initial design was abandoned. After a revision, Schrölkamp's design was considered the only practical option. Other designs that were acceptable to the citizens' initiative proposed a larger and almost twice as expensive new building. In response, the heirs of the Baumgarten family threatened a copyright dispute, leading to the implementation of Schrölkamp's design.
Between June 2005 and March 2007, the new building was built with a usable area of 794 square meters, a gross floor area of 1,576 square meters, and a gross volume of 5,081 cubic meters. The construction costs amounted to . The in-court opening ceremony took place on May 10, 2007, in the presence of the then Prime Minister Günther Oettinger, State Secretary , the then Mayor of Karlsruhe Heinz Fenrich, the architect, and other guests of honor. The extension building was occupied in 2007.
Interim quarter 2011 to 2014
Since German reunification, the Federal Constitutional Court has received significantly more complaint cases, which means that the original form of the Baumgarten-Bau no longer meets the increased requirements. Along with a planned extension towards the Botanical Garden, renovation work on the existing buildings became necessary in 2011. To manage the extensive construction, which spanned several years, the 16 justices and approximately 60 staff members at the time relocated to interim quarters for three years. The interim quarters, situated to the northeast of the Baumgarten structure, consisted of the previous General Kammhuber barracks located at Rintheimer Querallee 11 on the eastern boundary of the Hardtwald forest. The architects from Stuttgart's Lederer Ragnarsdóttir Oei firm were tasked with designing a standard office and semi-public space in a representative style. Similar to the Federal Constitutional Court's main headquarters at the Schlossbezirk, the interim office – also known as Dienstsitz Waldstadt (Waldstadt office) after the neighboring Waldstadt district of Karlsruhe – consists of various interconnected structures with corridors and connecting wings. The architects designed the building to have a resemblance to the main official seat. Right after entering the office, a light green carpet stands out against a glass picture. The plenary hall, formerly a training hall of the barracks, now has a lateral stair tower attached to it, leading to the press gallery. This addition gives the hall a sculptural appearance from the outside. Inside, there are two glass porches on each long side that open onto the courtyards. The roof overhangs created by these porches are reminiscent of the architectural style of the 1950s. The interim building took up certain forms of the Baumgarten building and used them as a model. The design aims to appear neither ostentatious nor too spartan. The return from the Waldstadt headquarters to the Baumgarten Building took place from September 26 to 28, 2014.
The barracks buildings converted into a court have been used on an interim basis by the Federal Court of Justice since 2020, as one of the office buildings at its headquarters in Herrenstraße, known as the West Building, is undergoing renovation. Additionally, the Karlsruhe Federal Police Inspectorate is housed in four other side barracks buildings.
Renovation 2011 to 2014 Many years of operation, comfort deficiencies, and an analysis of the building fabric showed that a structural and energetic refurbishment of the Baumgarten-bau had become necessary. For this reason, the buildings underwent a three-year refurbishment from August 2011 to August 2014, at a total cost of around . In addition to retrofitting and optimizing the basic fabric, the challenge was to preserve the listed ensemble.
The distinctive façades with wooden windows made of Red Oregon Pine and single glazing could not be kept. They were replaced with double-glazed windows and had no reflective coating to preserve transparency. Concrete parapets were given more energy-efficient fully insulated sandwich panels, and the elaborate cast aluminum panels were removed, cleaned, and re-installed with reinforced fixings. Inside, pollutant remediation was necessary in some areas. Areas whose functional use had been eliminated were redesigned accordingly. To ensure fire protection, steel supports were ground down and recoated. In addition, the entire technical building equipment was brought up to date, new building and communication technology was installed and efficient LED lighting was installed. The work was carried out by the Rotterdam architectural firm West 8, which won an international competition in 2012. The installation of cooling ceilings or so-called Coolwave elements in all offices contributed to improving comfort, as did the installation of carpeting and sound-absorbing elements to improve acoustics and the installation of perforated sunshade elements. Interior finishing measures included the renewal of sanitary facilities and the replacement of radiators, floor coverings, and furniture.
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