Lichthof Facade and Roof
German Foreign Ministry, Berlin
Building architect: Müller Reimann Architekten
Engineer: Schlaich, Bergermann & Partner
1999

The Lichthof is the public space of the new German Foreign Office in Berlin.  Conceived by the architects Müller Reimann Architekten as a light-filled courtyard with a glazed roof and facade onto Werderstraße, it is used as an orientation space for the public who enter the building and as a space for semi-public and institutional gatherings.
The space is seen in relation to the square on the other side of Werderstraße formed by Schinkel's Friedrichwerdersche Kirche and his Bauakademie which is still to be reconstructed in the effort to restore and revitalize the ancient centre of Berlin.
On an urban and cultural level the facade of the Lichthof forms an important boundary through which the public views the Foreign Office, the civil servants view the city, and in which the images of both sides are reflected.  The boundary condition and the north-facing orientation of the courtyard are the basic conceptual parameters of our design.

We took the parallel planes of the deep roof beams and the facade and used the possibilities of reflectivity, transparency and colour afforded by various glass coatings and specular metal to ensure that sunlight will be reflected back into the shadow, throughout the year.
In the roof, we mounted specular aluminium reflectors at such an angle that when the sun is at its lowest in midwinter sunlight still projects into the back of the space.
In the facade, we used three glass coatings to modulate reflectivity of heat, sunlight and colour:  Heat is reflected by an external coating on the single-glazed water-clear laminated vision glass panels to prevent  condensation.  Light is reflected by an additional colourless semi-reflective coating on the central area of the glass panels to create the impression of a semi-transparent mirror floating within the facade.  Special dichroic coatings were applied to horizontal bands of glass cantilevering from the facade.  This coating divides sunlight into two halves: transmitting and reflecting opposite ends of the spectrum to produce a constantly changing field of colour on either side of the facade.
In addition to the direct sunlight, the coatings on the facade enhance the strength of the reflection just sufficiently for it to compete visually with objects seen through the glass.  This superimposition of real and reflected image increases the awareness of the Lichthof facade as a boundary, but it can also be seen as a metaphor for boundaries in general, which relates strongly to the political function of the Foreign Office itself.

James Carpenter and Luke Lowings produced concept and detail design in collaboration with the architects and engineers while working together for JCDA in New York.