Art of glass.

A shed structure provided the model for an art museum in a Swiss city with an industrial history. The architects' poetic rigour supplied lyricism.

The industrial city of Winterthur, north of Zurich, has a history of manufacturing textiles and machinery, some fine medieval architecture and good civic buildings. Of these last, the Neo-Classical museum by Rittmeyer and Furrer, completed in 1916, possesses one of the most important art collections in the country, including French nineteenth-century paintings and early Modern American works. Built up gradually over the 80 or so years of the museum's existence, the collection grew to the point where it became plain that more space was required urgently, particularly as the building was partly taken up by the city library and a small natural science museum. Under pressure from the local Society of Arts, the city authorities agreed to the provision of a temporary extension, commissioning Annette Gigon and Mike Guyer, architects of the Kirchner Museum in Davos, to design it.

These architects are masters of the evanescent. The Davos museum (dedicated to the works of Ernst Ludwig Kirchner) is clad in different kinds of glass and sits quietly among mountains, the milky glass skin refracting and diffusing the alpine light. Galleries within, designed with the utmost austerity, promote calm contemplation of the works. The approach has been adapted to the exigencies of the Winterthur brief which provided a limited budget and asked for at least 1000 square metres of floor space.

Gigon & Guyer's lithe extension floats off into the Liebewiese (Park of Love) behind its substantial host, its corporeality masked by a shimmering veil of bluish-greenish glass. The building is essentially an industrial shed on stilts, rectangular in form and with a saw-tooth roof. What could, in an area of villas and parks, have been a harsh proximity to its Neo-Classical neighbour has been rendered poetic by the skin of profiled glass which breaks up into vertical strips, providing a kind of glass skirt around ground floor parking. A trapezoidal hinge, clad in silvery grey metal and reminiscent of industrial flues, links the first floor galleries to the first floor of the main museum. This contains a staircase lined with plain wooden panels, and not the ramp that external appearances suggest. Similarly surprising is the spatial variety achieved by the architects within the straitjacket of the orthogonal plan. There are nine galleries, given five different sizes and proportions, and different degrees of seclusion. Doorways are offset so that the visitor is gently encouraged to meander, and variety is quietly experienced rather than perceived consciously.

All the galleries are illuminated by the cool light which pours in through the rows of north lights overhead and washes over large expanses of plain white wall. Three large windows, one in each side, are set at floor level framing the tops of trees outside and creating lyrical intrusions into calm white spaces. It will be surprising if this building does not become more permanent than its progenitors envisaged. It was put up in record time, with little money; the structure is basic prefabricated steel frame, and finishes are similarly basic: plain plastered walls and polished concrete. All of this is in striking contrast to the opulent museums and art galleries presently making their appearance all over the world. Yet the architects have achieved timelessness in the spaces they have made here, and their sensitivity to the works on display, to the requirements of curators and visitors' pleasure, is impressive. You are reminded once again that simplicity, poetry and efficiency are produced by real appreciation of complex things.