Under the curve.

This house, simultaneously cave and tent, ingeniously manipulates structure, plan and sectional geometry, and the site to maximise views and the incidence of sunlight.

One winter day, Michael Szyszkowitz and Karla Kowalski received a telephone call from a psychotherapist couple practicing in Bad Mergentheim, a small town in Germany between Stuttgart and Nuremberg. Attracted by the firm's published work, they wanted to visit some buildings, and flew to Graz the following weekend even though it was almost Christmas. The architects soon received a commission for a family house including professional consulting rooms on a steep south-west facing site about 2000 square metres in area. Szyszkowitz and Kowalski sought to use the slope, creating a hierarchy of increasing privacy.

The lowest level is shared between consulting rooms, garage and services, the main middle floor contains living rooms and parental bedroom, and the top floor children's rooms. All floor plans show the same outline, but the house is terraced into the hill with a buried cellar at the back and a cascade of staircases linking the levels at the front. It has a great rounded metal clad roof which generates a powerful impression of shelter, without following a traditional tripped or gabled form.

The points noted so far might have been expected: the real departure from convention in the planning of this house is its skewed placing. Both contours and site boundaries suggested a building running parallel and perpendicular to the slope, as is standard policy with such sites and the case with neighbouring houses. Szyszkowitz-Kowalski saw the advantage of turning the building instead to get a longer front facing due south, and to profit from diagonal views in both directions. The apparently anarchic plan turns out to be disciplined by the roof structure. This divides the house into a series of notional bands, picking up various partition walls and turning them into structural elements.

On the west end three lines of structure terminate in rhythmic buttress-like projections containing planters which stress the formal intention, and their presence in early sketches shows their priority in the design. On its north-west and south-east sides, the building swings round to meet the site boundaries, on the latter with a stair marking a change of level. The main curves and angles of the plan are thus a consequence of the interaction of the site and the diagonally placed roof, though once created they are exploited to create a lively spatial movement within.

The roof edge is straight on the south side but broken on the back and north where the house runs into the hill. The line of the roof in plan is more or less taken up by the edge of the first-floor terrace, but the envelope on both upper stories follows a meandering line attending to the detailed spatial needs of the living room, its terrace, and the main entrance which is inflected towards the arriving steps. Most of the living room is two storeys high rising to the curved roof with the landing to the children's rooms presented as a bridge. This complex three-dimensional arrangement produces a rich variety of spaces and views tempered by the constant presence of the simple roof sweeping over. The landscape seems to flow into the house, and as the architects see it `the whole house is a landscape'.(1)

As usual with Szyszkowitz-Kowalski, tectonic expression is restricted to selected elements like the struts supporting the roof and the structural ribs projecting from its upper surface. Walls were, as usual, made roughly of blockwork then rendered and painted outside, plastered inside, covering lintels and all. This avoids any potential problems with inelegance of coursing and joints that might result from the irregular forms. This kind of technique, where the architect knows that secondary cladding will hide the initial carcass, was of course widespread in pre-modern architecture. It runs against the discipline of assembly so often pursued as a rhetorical theme in the twentieth century, but permits in exchange a high degree of formal and spatial freedom.

(1) Taped interview with them by the author, 1995.