With a light heart.

The transformation of a rather dull city block in Oslo's business quarter into a lively semi-public space surrounded by social events.

The oldest part of Oslo (Christiania) dates back to the King Christian IV plan of 1624, which imposed a regular gridded pattern on the urban grain. Within this context, each city block can be regarded as a kind of 'super building', with individual elements reinforcing a common and intrinsically harmonious theme. But in reality this homogenisation is the exception rather than the rule. At Christiania Qvartalet (a mixed redevelopment of a large 1930s concrete shell), the city block is distinctly heterogeneous. Components of the block date variously from the 1840s to the mid twentieth-century Seamen's Union. On an adjacent block is the fine but rather dominating Royal Bank of Norway, built by Lund & Slaatto.

Niels Torp's response to this plurality of styles and forms is a respectful yet muscular Modernism. The new components extrude through the block, registering as a set of contextual exercises, intended to knit together the disparate townscape. On Grev Wedels plass (AR July 1995, p19), to the south, the new insertion carries on the scale, proportion and rhythm of the existing elements, down to its stark, rusticated base. On Revierstredet to the north, the building affirms its presence in a much more direct way, through a layered composition of concrete and glass. The boldly articulated bays are infilled with curtain walling that reflects and refracts Oslo's distorted cityscape across its glossy skin.

Yet the real drama of the building is not in how it addresses the street. For behind the severe elevations is, literally, a light heart; a semi-public atrium carved out of the space in the middle of the block. Like Lund and Slaatto's Kreditkassen bank (AR January 1990) and the old parts of Torp's Aker Brygge (AR August 1990), Torp's logical response to the harsh Norwegian climate is to roof over the interstitial gaps between the buildings, creating a magical, moderated world of generous and exciting spaces, animated by the constant diffusion of light through the glazed roof. In itself, the principle is unremarkable, yet here it is applied with consummate skill and sensitivity. Most of the surrounding office blocks are occupied by small firms (there are around 10 tenant organisations altogether) who share a communal restaurant, cafe and auditorium. The effect is like a microcosmic fragment of city, with all its diversity, animation and potential for social exchanges. Part of the main courtyard is cobbled, reaffirming the scheme's hard-edged, urban sensibility. The approach prompts inevitable comparisons with Torp's seminal SAS headquarters (AR March 1989), which memorably transformed corporate office into a thriving social organism, arranged around an internal street. Here the humane rigour that is a distinguishing feature of both Torp's buildings in particular, and Norwegian architecture in general, is again much in evidence.