HELSINKI HINGE.

A major new building in Helsinki attempts the complex task of trying to draw together very different urban elements to make a coherent city pattern.

Helsinki has a dense Neo-Classical centre with a charming Esplanade park lined by most of the famous shops; to the north is Senate Square, dominated by Engel's Lutheran cathedral, and to the east, the Esplanade opens onto the harbour. But at the west end of the Esplanade, the precise structure falls to bits. A long wide street, Mannerheimintie, straggles away northward and along it, the connected tissue quickly breaks down into a succession of object buildings. On the left is the heavy Neo-Italianate Parliament Building by J. S. Siren (1931), and the turn-of-the century National Museum by Saarinen, Lindgren and Gesellius. Opposite the Museum is Aalto's Finlandia Hall, newly refaced and gleaming, on a parkland site which slopes down towards Toolo Bay, an inlet of Helsinki's enormous natural harbour.

Until recently, the area opposite Parliament was a mess. Stretching from the solidity of the General Post Office's '30s Rationalism northwards to Finlandia Hall and the southern shores of Toolo Bay was a muddle of railway lines and sheds that somehow became detached from the flank of Saarinen's great station. This tangle was well below Mannerheimintie, almost at the level of the shores of the bay. Now, the part opposite Parliament is largely to be made into a park, and the whole has been ordered from the south by two large new buildings.

First to be completed was Steven Holl's controversial Kiasma, the museum of contemporary art (AR August 1998). Covered in metal and glass, its west front forms a concave curve against Mannerheimintie, starting roughly from the equestrian statue of Marshal Mannerheim (the soldier-hero of Finnish independence), and ending with a salute to the parliament building on the opposite side of the street. Kiasma's east side is straight and parallel to Jarvi and Lindroos's post office, forming a pedestrian gateway to the park which, as it moves north, suddenly changes with ramp and steps from the plane of Mannerheimintie down almost to shore level.

The other new ordering structure is north of the post office, and it reflects the '30s building's width in an almost square plan. Designed by SARC Architects, the new headquarters of Sanoma, the company which owns Finland's main daily newspaper, Helsingin Sanomat is fundamentally an office block, but a very interesting one. It is an almost total contrast to Kiasma. While Holl's building is sensuously curved and idiosyncratically ordered, the SARC one is rigorous and rational. Holl ignores the city grid at a point where it has fallen apart; SARC attempts to re-invent it and carry it to the lower level. Kiasma is (by its nature as a gallery) largely opaque and imperforate; Sanoma at first seems almost totally transparent and penetrable.

It is a large glass block, given scale by metal brise-soleil on the insolated sides, and on the north by a remarkable outrigger structure of metal cables and spars which stabilizes the otherwise free-standing nine floor high top-hung glass wall. This encloses the building's great gesture, a huge internal Media Square -- the focus of a new internal semi-public set of spaces. Each corner of the square plan has an entrance, and between these, there is a diagonal cross of semi-public circulation, which defines the nine-storey high Square. The dominant axis runs between revolving doors at north-west and south-east corners, and, like the big space, it ascends the height of the building. On the ground floor, it will have a cafe and shops, and it will in effect be a grand urban arcade. The other axis is less pronounced, for it is interrupted by the main lift bank, but at its south-west end, it offers an internal public escalator which links park level with Mannerheimintie, 3.5m higher up.

The Media Square is a grand if slightly puzzling space. It receives luminance from the great north glass wall, and from wide strips of glass in the roof which follow the internal sides of the triangular plan. So it is full of light, and it looks over the park-to-be and Toolo Bay with increasingly dramatic views as you go up through the building. At the same time, it spills light into the office trays which overlook it (and of course the views) through simple glass partitions. The puzzle is to decide how to use it: it is a fine space, and a welcome addition to the (semi) public realm but its very dimensions seem rather daunting to those given responsibility for organizing exhibitions on its floor.

The Square is animated by the main stair, and a wide bank of transparent lifts on the southeast flank which whizz up and down in dance choreographed by chance. They disappear into a wide gulch from which warm light floods upwards into the cool grey space from the basement. Down there are the office canteen, and meeting rooms, panelled and floored in ruddy wood.

The other staff areas are the offices. Above first floor, these are formed into two triangles of space which of course receive light from the perimeter (often through cellular offices) and from the big voids. Across the full-height arcade, bridges link the triangles, and animate the scene. So from the ground floor you can gain a notion of the busy life of a newspaper office behind the glass partitions. The floors themselves are like other periodical publishing offices, placeless plains, though when I visited them, they seemed less messy than most, perhaps because they were only just occupied. (Incidentally, the public is prevented from getting to the private areas of the building without permission by simple electronic card systems which prevent unauthorized access to vertical circulation.)

Just as the life of the offices is displayed inside, it can be glimpsed through perimeter walls. They are double skinned, with a rain screen 800mm outside the inner layer. In summer, hot air from the cavity is released at roof level: the cooling effect of convected air rising through the cavity is expected to reduce mechanical chilling loads significantly. In winter, openings to the cavity are closed, so that it becomes a buffer against heat loss. Such arrangements are becoming normal in sensible northern countries, but the Sanoma building celebrates the device by allowing the external layer to stretch out beyond the basic cube to form welcoming wings over each entrance. In the south-west corner, the device is used to generate external balconies opening from the bigger office triangles offering splendid views of the inner city.

Interaction between interior and exterior, private and public, is the essence of this building. Doubtless, some will argue that it is also helping to tip the balance from public space to semi-public areas into which people are allowed only with owners' permission. Yet it cannot be accused of increasing mallification. It adds significantly, elegantly and decently to the public realm of the city.