The Vallon du Cossy building is a new 14-unit condominium complex in the Vallon du Cossy district of Nyon.

The building is L-shaped, the two branches comprise 2 and 4 levels above ground respectively. The entire building rests on a basement level which constitutes the entrance hall, cellars and parking lot.

Geotechnical studies revealed the presence of groundwater. To remedy this, a generalized invert with a bentonite based mat waterproofing was chosen.

The excavation enclosure is created using embankments where space permits, and a Parisian wall where the road and one of the existing buildings are close to the excavation.

The building’s load-bearing structure is designed to be rational. It is made entirely of reinforced concrete, with 22 cm slabs supported by walls and columns, all resting on a generalized invert.

Between the apartments and the parking lot, the load-bearing walls of the apartments have been modified, with load-bearing walls suspending the slab and freeing the basement of most of the load-bearing walls. The choice of load-bearing walls also avoided the need for a thick, costly distribution slab.

The building’s stability in the face of wind and seismic action is ensured by the circulation shaft and facade walls.

The floor slabs, common area walls and cast-in-place staircases are made of Type 4.14 exposed concrete.