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Article from issue 1+2/2009 »Roofs«

House near Adnet

documentation p. 41 - 45
Architect Maria Flöckner und Hermann Schnöll | Structural Engineer gbd |

This residence is nestled close to the earth in Tennengau, a landscape south of Salzburg characterized by a smattering of lone farmsteads. Integrated in a gently sloped site – at one corner the sandwich-like structure intersects the terrain, at another spot it seemingly floats above the meadow – it creates a spatial continuum, embellished by loosely scattered wooden boxes which accommodate the whole range of functions a house requires. Because of the importance accorded by the clients to coming and going, during the design process, the streetscape and the landscape evolved into decisive poles. The architects interpreted the spacious garage as
extended parking bay under the large roof, shielded from the street by a translucent facade. A view through the house to the meadows, farmsteads and mountains can already be had while getting out of the car: The living space and the garage are separated by glass panes. The two planes – the floor and the ceiling – frame the fully glazed living area, providing a panoramic view of the landscape. Changes in the weather and seasons are
always perceptible here, tempered by triple glazing, underfloor heating and a floor stove. The cantilevering concrete “sandwich” – which extends as far as is allowed by the setback requirements – creates a transition zone between interior and exterior that is enlarged at the corners to become a patio or veranda. For more privacy – and as sun protection – a black synthetic curtain that permits views to the exterior shields the glazed areas. Light-toned curtains provide an additional screen for the bedrooms, which are partitioned off from the great space by sliding and revolving doors, as well as by the cubes. These modules containing bathrooms, dressing rooms and other storage spaces – lit in part from above – are a prerequisite to living in the minimalist, painstakingly furnished great space on a day-to-day basis. The boxes’ outer surfaces are sheathed in an inverted tree pattern– which make the cubes seem lighter and introduces a vertical element in a house in which the horizontal otherwise dominates. The large cantilevers – reaching 8 metres on the northwest corner – were the determining factor for the roof’s structure. The decision to leave the concrete’s underside exposed posed a considerable challenge with respect to potential sagging and plastic deformation of the structure. The architects had to give up on massive aerated autoclaved concrete, their first choice, because it was rejected by the structural engineer and different contractors. Instead, an inverted composite roof system was employed: Suspended from the framework – which is made of steel beams – by dowel bolts is a reinforced-concrete compression plate. The steel framework is supported on square columns of steel hollow sections that are arranged in the outer cores’ corners, as well as along the segments of the facade that are straight. The cross-bracing within the core walls provides horizontal stability. During construction, the steel members were installed first. Then the scaffolding for the formwork was set up, and the concrete was poured. This solution also gives the impression of a solid, unified roof. An extensive green roof tops it all off. Oblique skylights oriented in different directions penetrate the roof. With the help of a crystal-forming substance, the swimming channel flanking the south side of the residence was also executed in exposed concrete. These crystal formations penetrate the capillaries through osmosis, making the concrete highly resistant to water pressure and aggressive chemicals.

Details
1:20 Sections
1:400 Floor plans
1:400 plan of steel structure
1:400 Sections
1:4000 Site plan