ROCK GARDEN.

HOUSING, MONTPELLIER, FRANCE 

A speculative housing block in Montpellier has been transformed by the treatment of its external walls.

Attempting to invest speculative housing with a measure of formal invention is generally a thankless enterprise. Yet on an unremarkable housing estate in Montpellier, Edouard Francois has designed a new apartment block that uninhibitedly explores and celebrates materials and nature. The brief from a property development company was for 64 flats and 47 parking spaces on a tight budget of FF6500 per sqm. Francois's proposal followed a familiar and logical pattern based on making the most economic use of the site and exploiting techniques of prefabrication. The plan is simple and straightforward. Flats for the most part are single-oriented either to the east or west, entered from a spinal central corridor. The curved block inscribes a gentle arc in the landscape and gradually steps up from three to six storeys along its length, terminating in a prow at the south end.

The most radical aspect of the scheme is the treatment of the exterior as a massive rock face that will eventually bloom into a spectacular vertical garden. Moored on a solid stone base, the walls are formed from a series of prefabricated concrete panels measuring 2.77m x 1.35m. The external face of each panel is clad in a layer of steel wire cages, containing loosely compacted stones. The model is clearly the gabion cage, typically employed in river and highway engineering as a retaining element. Architectural interest in these basic yet adaptable structures is growing- Herzog and de Meuron's Napa Valley winery (AR October 1998) appropriated gabion cages to construct external walls, with different grades of stone used to filter light and air. Here the caged stone is simply a uniform external layer, but its monolithic appearance will be eventually transformed by vegetation implanted within it.

Panels were assembled in several stages. The steel cages were set within steel formwork and studded with a double layer of frost-resistant pebbles. A layer of sand followed, then seeds of rock plants contained in grow bags. The ends of the cages are set within a layer of concrete that forms the inner face of the panel. On removing the formwork, the sand was gently shaken out, leaving the soil and seeds. Cast-in lifting hooks enable the panels to be easily lifted into position and fixed onto the structural frame. A watering system installed between the joints of the panels will nurture the emerging plants.

The elevations are also articulated by various types of balconies, some enclosed by rustic wooden fencing, others by timber panels. Larger enclosed cabin-style balconies on the east side are supported on angled steel tripods and connected to individual flats by narrow walkways. Despite the building's unorthodox appearance, flats were quickly snapped up by adventurous buyers. The stone cages have a curiously sensual, primeval quality, like the ancient dry stone walls in fields. It will be fascinating to witness their slow metamorphosis into a modern hanging garden. C. S.

1 The curved housing block inscribes a gentle arc In the landscape.

2 Large balconies, some enclosed like outdoor rooms, articulate the mass of the stone walls.

3 External face of prefabricated wall panels consists of steel gabion cages, adapted to form cladding. The effect Is dauntingly geological, but walls will eventually be softened and animated by planting.

4 Detail of stone cage. Frost-resistant pebbles are loosely compacted in a steel mesh basket.

5 Rustic balcony terraces.

6, 7 Larger enclosed balconies are supported by curious tripod legs, and walkways link balconies with flats, creating an aerial external realm.

Architect

Edouard Francois, Paris

Project team

Edouard Francois, Valentine Chanut, Sebastien Duron. Herve Potin, Cedric Martenor. Daphne Bouvard, John Aubert

Photographs

Paul Raftery