An office building composed of two buildings dating from the 1970s, frames an interior garden of approximately 5,500 m². Its restructuring is an opportunity to requalify all the exterior spaces into a coherent, qualitative and sustainable landscape.

The central garden is divided into two parts of very different natures, separated by a covered walkway. The larger part is made up of a vast lawn covering a parking lot. The second, located on a lower level, is characterized by a few large trees planted in an open garden.

The project plans to introduce a strong vegetal presence in the form of a miniature forest uniting the two levels. This unified landscape is crisscrossed by paths that multiply situations. The technical constraints are decisive. The challenge is to achieve a common writing, despite the differences of the locations. Planting on slabs requires a technicality that we have developed in many projects.

The garden on slab is made up of a constant layer of soil of about 80 cm, shaped by islands of vegetation thickened by a filling of expanded polystyrene blocks. It incorporates the planting of trees always  arranged in line with posts of the parking structure. The successive and irregular undulations draw a rich landscape. This unexpected topography is meticulously worked to create slightly sunken gravel paths, whose slopes and drainage trenches contribute to rainwater management.

The open ground part is densely planted (1 tree / 14 m²). It is crossed by a sunken path, whose central channel collects rainwater to lead it to a retention basin that constitutes a focal point in this part of the garden.

All the paths are particularly well maintained. The embankments that surround them are the foregrounds where the ground covers of a rich and abundant undergrowth are implanted. They constitute gardens in a wider landscape whose simpler ground covers do not require such meticulous maintenance.