Swedish salon.

This restaurant strikes a new relationship between the social life of the interior and the beauties of its landscape park by re-working an ancient device: the veranda.

Gothenburg's botanical garden, its Tradgardsforeningens park, is part of the ramparts of the old centre. Since 1887, it has had a restaurant with what in Swedish is rather charmingly called a kabare-salong, where people come for jollies, different according to the time of year.

The first salong burnt down in 1965, and its successor suffered a similar fate in 1996. Winners of the subsequent international competition were a local firm, Studio Gron whose principals are far from parochial: Fredrik Lund is Norwegian, and of his other three colleagues, one is a Dane, another a Finn, with only one a Swede. As the name indicates, the firm is interested in exploring relationships between architecture and nature, and the site of their new restaurant was clearly exactly right for them, for it lies between the busy inner-city ring and the picturesque park with its nineteenth-century palm house partly hidden among fine trees.

Studio Gron's strategy was to build a relatively massive two-storey building against the road to provide a sound and pollution barrier and, parallel to that, a 63m long strip of double-height space that overlooks the park through a great glass wall. The masterstroke of the parti was to form a veranda along the whole of this wall (and projecting beyond its ends). Only 3.5m wide, the veranda does not seem at all mean or pinched, for its inner wall is glass, and the outer one an open rectangular lattice screen. An intermediate inside/outside space, the veranda becomes an extension of the public rooms behind the glass, where people can come to dine or chat before going out into the terrace beyond, to which the dancing moves on the long greenly-luminous Swedish summer evenings.

Studio Gron (working with landscape architects Snohetta - an interesting new role for the designers of the Alexandria Library) have planted deciduous climbers at the base of the lattice. These they hope will provide a screen that will continuously change in texture, colour and scent following the seasons: in spring, the flowers of clematis Armandii and montana will lighten the screen; in summer, the glass wall will be shaded by the leaves of hops and vines, and the veranda will be scented by honeysuckle; in autumn, Virginia creepers will make a scarlet veil. And in winter, when almost all the leaves will fall off, the plants will be pruned to allow low winter light into the chain of glazed spaces. The timber slats of the screen are of larch which will weather silver-grey, when the architects hope that it will have the simple functional dignity of traditional Scandinavian farm buildings (the block walls and concrete structure on the road side are clad in thin close-set larch strips, so the whole block has visual continuity).

While larch forms the outside, birch lines the interiors. Birch strips and birch plywood, both gently oiled, clad the long wall opposite the glass front, and their smooth paleness, made slightly richer by the oil, helps fill the volumes with clear warm light. The long glazed strip is divided into three parts. From the entrance in the middle of the long plan, you can turn either right to the restaurant, left to the big room or straight ahead to the bar.

The entrance axis is the only place in which the two-storey configuration of the back of the building comes right through to the great glass wall. Here, at the upper level is a platform with a bar which overlooks the dancing downstairs. The lower bar is given intimacy by the floor above, and acts as a buffer between restaurant and the big room. These two main spaces are made very different by the undulating birch wall. The narrower, the Tradgarn restaurant, can accommodate 200 diners in a surprisingly intimate atmosphere, made more so by a plethora of lights hanging from the black ceiling (which, with its downlighters, actually provides most of the illumination). At night, the hanging lights reduce the apparent height of the space, and the row of big softly glowing suspended white cylinders helps contain a space that might otherwise spill out into the dark through the glass. The black ceiling continues over the other main space, but here, there are no hanging lights. Everything is illuminated from the ceiling, and the volume (which can take 500 people sitting down at a banquet, or 2500 at a ball) is intended to seem big, but its scale is broken down at the edges with stairs and galleries, and wall-wash lighting on the birch.

Throughout, everything is handled with simplicity and tectonic sensitivity. Balustrades for instance are simply fabricated of rods and fiats; the front screen is of vertical rolled steel sections and quite rough-sawn larch slats. The birch is mounted with sophistication, reminiscent of the finessed handling of thin timber sections and plates in the work of Asplund and Nils Einar Eriksson who made Gothenburg's wonderful 1930s concert hall seem like the inside of a violin. Such sensitivities are reemerging in Sweden at long last. The Tradgarden building is a fine example of the renaissance, with its understanding of subtle relationships of building to nature, interior to outside, scale of space to human use, and materials to our senses.

Architect Studio Gron

Photographs Ake E:Son Lindman