Natural forces.

This house on a breathtaking island site near Vancouver is clearly but beautifully abstracted from nature, through its sensual use of animate forms and natural materials.

Blue Sky Architecture has been around for quite a while now. The outfit emerged in the early 1980s (see AR February 1988) as a group of what at first appeared to be a Canadian version of the Californian woodbutchers. Yet while that '60s hippies-in-the-woods movement was either faux-naif, or just plain naive, Blue Sky's work had a certain order and sophistication, even while having a lot of the freshness and robust pragmatism of what had been going on further south.

Perhaps this was because much of the work was on Hornby Island, a traditional haven for artists and intellectuals in the strait between the mainland of British Colombia and Vancouver Island. The clients expected something rather more than rough dwellings, and they certainly found it in the work of Bo Helliwell and his colleagues. Helliwell, trained as an architect in Canada and at London's Architectural Association School, taught himself the arts of practical building, learning from tradition and nature, and often leading the construction teams on site. He had become a perfect model of what Arts and Crafts architects would have liked to be 100 years before.

Since then, Blue Sky has changed somewhat. Helliwell and his partner Kim Smith have relocated in North Vancouver on the mainland, and their practice now tends to be rather more varied, though houses are still the main focus of activity; even though their clients are often richer than the ones on Hornby, they also want to live in close contact with nature. One of the latest completed projects is on Galiano, in the beautiful tree-covered archipelago between Vancouver and the very large synonymous island which protects the Gulf of British Colombia from the forces of the ocean.

Galiano Island is long and thin, not far from the west side of the Gulf, almost echoing the coastline of its vastly bigger neighbour, the coastline of which sometimes seems almost to close over the Tricomali Channel. The site is long and narrow, between the road that runs down the island's back and the low sandstone cliffs that drop to the seashore. The single-storey plan adopts a sinuous front to the west to make the most of the views and sunlight. To the east it is rather more utilitarian, with an entrance court flanked by the less important bedrooms and the garage, all below the steep bank that slopes up to the road.

This long but diverse plan is held together as a diagram and series of spaces by a very strong structural idea. A straight central ridge runs down the whole thing from south-east to north-west. At right angles to the 14in (360mm) diameter ridge logs are 9in (230mm) rafters similarly made of turned cedar. Before the roof coverings were put on. the whole thing looked like the skeleton of a fish (and internally it still does have vaguely animate resonances). Because of the sinuous curve of the west wall and the orthogonal geometry of the structure, the whole west side of the building undulates not only in and out but up and down to form an organic form which is in the end derived from the structure of the site itself. This dipping and swooping roof is clad in copper, the flat roofs are covered in turf. At each end of the plan, a skeletal form emerges, the rafters of the roof continuing their rhythm to enclose virtual rooms which, as creepers grow over them in summer, will presumably be more clearly part of the linkage between the sequences of internal and terrace spaces.

Internally, the big volume is partly ordered by the big (12in-300mm) turned cedar posts that support the roof ridge. These give a rhythm that can be seen to continue, even when the space is divided by partitions to form smaller rooms. The gentle aroma of the cedar structure fills the place with the comforting half-remembered scent of an old-fashioned school pencil box. The main spatial sequence is southwards from the entrance area, via a gallery to the living and dining spaces which terminate in a huge freestone fireplace wall. This whole area is floored in cherry-wood, which holds the sequence together. To the east behind the gallery, but still part of the overall volume, is the kitchen which is designated by a change in floor covering to stone.

Luminance as well as structure holds the place together. A long rooflight runs down the whole east side of the ridge flooding the spaces with calm radiance that contrasts with the more sparkling and sunny light from the sky and sea to the west. These are potentially so intense that the west wall is shaded by a long overhang and its glazing is in thermally reductive glass. Sliding doors open onto the terraces which are very gently sculpted from the natural rock, changing it just enough to make it into a series of more-or-less level surfaces.

As you walk over them at night, with the trees and the roof's curve outlined against the stars and sea-blink, you can hear the soft whooshing hiss of the whales drawing breath as they swim up the channel. It is difficult to think of a house that makes more close contact with nature, partly because in itself it is such an elegant abstraction of natural forces.