Transformation of the Reichstag German parliament building with Cofrastra® steel flooring sheets

In the 1990s, not long after its reunification, Germany rebuilt its historic parliament building, the Reichstag - a design which combines respect for the past with a future full of hope. In this renovation project, Cofrastra® steel decking from ArcelorMittal was used for the composite flooring system.

Detailed information

Architectural concept

The transformation of the Reichstag is rooted in four related issues: the Bundestag’s significance as a democratic forum, an understanding of history, a commitment to public accessibility, and a vigorous environmental agenda. As found, the Reichstag was mutilated by war and insensitive rebuilding. The reconstruction takes cues from the original fabric - the layers of history were peeled away to reveal striking imprints of the past such as stonemason’s marks and Russian graffiti − scars that have been preserved as a ‘living museum’. In other respects it is a radical departure. Within its heavy shell it is light and transparent with its activities on view.

The dome: An important landmark in Germany's capital city

The public and politicians enter the building together and the public realm continues on the roof in the terrace restaurant and in the cupola where ramps lead to an observation platform, allowing the people to ascend symbolically above the heads of their elected representatives in the chamber. The cupola is now an established Berlin landmark. Symbolic of rebirth, it is also fundamental to the building’s natural lighting and ventilation strategies. At its core is a ‘light sculptor’ that reflects horizon light down into the chamber, while a motorised sun-shield tracks the path of the sun to block solar gain and glare. As night falls, this process is reversed. The cupola then becomes a beacon on the skyline, signalling the strength and vigour of the German democratic process.

Being clean and sustainable

The building provides a model for the future by burning clean, renewable bio-fuel – refined vegetable oil − in a cogenerator to produce electricity, a system that is far cleaner than burning fossil fuels. The result is a 94 per cent reduction in carbon dioxide emissions. Surplus heat is stored as hot water in an aquifer deep below ground and can be pumped up to heat the building or to drive an absorption cooling plant to produce chilled water. Significantly, the building’s energy requirements are so modest that it produces more energy than it uses, allowing it to perform as a mini power station in the new government quarter: it is an object lesson in sustainability.


Client: Bundesrepublik Deutschland
Site supervision: Büro am Lützowplatz AG (BAL AG)
Stuctural engineers: Leonhardt Andrä & Partner
M+E services: Kaiser Bautechnik Ingenieurgesellschaft mbH, Kuehn Bauer Partner, Fischer - Energie + Haustechnik, Amstein + Walther, Planungsgruppe Karnasch-Hackstein
Quantity aurveyors: BAL AG, Davis Langdon & Everest
Lighting consultant: Claude Engle
Acoustics: Müller BBM GmbH, IKP Ingenieur Büro Knothe und Prof. Dr. Georg Plenge
Catering facilities: LZ Plan-Team für Verpflegungstechnik GmbH
Conservation consultants: Acanthus
Lifts, materials, & handling technology: Jappsen + Stangier
Cladding consultants: Emmer Pfenninger Partner AG
Environmental engineering: Müller BBM GmbH
Fire protection: Prof. Dr. Wolfram Klingsch
Certifying engineer: Dr W Stucke

Technical details: Facts & figures

Cost: 600 million DM
Total area: 61 166 m²
Net Area: 11 200 m²
Length: 137.4 m
Width: 93.9 m
Height: 47 m
Number of storeys: 6 + Dome
Competition first stage: 1992, second stage 1993
Construction begun: July 1995
Topping out ceremony: 18 September 1997
Official opening: 19 April 1999

Workforce and construction

  • More than 25 trade contractors
  • 240 workers on site each day during demolition
  • Up to 46 people in Fosters’ Berlin office
  • Total number of drawings submitted is 1100, presented in 65 folders
  • 45 000 tonnes of demolition material removed from the central area of the chamber in 35 truckloads per day from October 1995 February 1996 using a caterpillar machine with a 43-metre boom. Altogether, one third of the fabric removed.
  • Twelve fairfaced concrete columns in the chamber, each weighing 23 tonnes, carry the loads of the dome.

Light sculptor (cone)

  • Weight: 300 tonnes
  • 2.5 metres across at its base, where it punctures the chamber ceiling, widening to 16 metres
  • Covered with 360 highly reflective glass mirrors
  • A computerised sun-following moveable shield powered by photovoltaic cells, prevents penetration of solar heat and glare


  • Height: 23.5 m
  • Diameter: 40 m
  • Weight: 1200 tonnes
  • Steel: 700 tonnes
  • Clad in 3000 square metres of laminated safety glass — two layers of glass with an intermediate layer of vinyl foil - panel size 5.1 m x 1.8 m max.
  • 1.6 metre clear width helical ramp acts as a stiffening ring for the cupola with ramp, cone, and covering integrated into a delicate structural balance; all elements are hung from exterior structure.
  • Observation platform height 40.7 m

Ecological features

  • Natural ventilation in the chamber using fresh air drawn up by the cone through the chimney effect.
  • Heat exchangers recover and reutilise warm air not expelled through the dome.
  • ‘Intelligent windows’ comprise a manually operated inner layer and a security-laminated outer layer which draws in fresh air via ventilation joints.
  • Renewable vegetable bio-fuel burned in a co-generator produces clean electricity, reducing annual carbon dioxide output by 94 per cent.
  • Surplus heat stored in natural aquifer which provides hot water for heating.
  • Cold water is stored below ground to provide cooling via chilled ceilings in hot weather.
  • Photovoltaic cells cover 300 square metres on south roof.


  • Approximately 750 seats, one for every MP, arranged according to respective party groupings
  • Rooftop restaurant for MPs, press, and members of the public
  • Press room and bar in ambulatory around the glazed soffit of the chamber, with views of parliamentary proceedings

Text: Foster & Partners

Project information

  • Berlin
  • Germany
  • Architect:
    Foster and Partners
  • 1992 - 1999
  • Client:
    Federal Republic of Germany
  • Engineering firms:
    Structural: Leonhardt Andrä & Partner
    M&E Services: Kaiser Bautechnik Ingenieurgesellschaft mbH, Kuehn Bauer Partner, Fischer - Energie + Haustechnik, Amstein + Walthert, Planungsgruppe Karnasch-Hackstein
  • Photographer:
    ©Nigel Young/Foster&Partners & ©ArcelorMittal