The sheltered entrance to this craggy school canteen building in France is fronted with a "forest" of slender white columns (+ slideshow).

Located in Tourcoing, northern France, the stone-like structure was designed by local studio D'Houndt+Bajart to create dining facilities for a neighbouring school and kindergarten.

Unlike the school buildings on either side, which are both built from red brick, the new structure was conceived as a hybrid of a cave and a treehouse – so its main volume is lifted up to first-floor level.

Its surface comprises a series of striations that provide a rocky texture and an uneven profile – prompting the building's name, The Roc.

"The main volume's effect of the building is spectacular – a rock suspended over the void, both solid and aerial," explained architect Vincent D'Houndt, who established his studio with Bertrand Bajart in 2006.

"The rocky aspect contrasts with the whiteness of the ground-floor walls, the jambs of the woodwork and the ground, reinforcing the floating impression of the rock."

Drawing on a vast number of references that vary from the Grand Canyon to Jules Vernes' science fiction novel Journey to the Center of the Earth, the team chose shotcrete to achieve the desired aesthetic.

This material – a type of concrete that is projected onto a surface through a pressurised hose – was moulded and hand-carved by a craftsman. It has a slightly pinkish tone, offering a subtle match for the brickwork.

"The facade reproduces perfectly the rock with its cracks, edges and rounding due to the erosion, geotectonic, and deformation of the strata," said D'Houndt.

Below this volume, the building's ground floor is slightly recessed to create a sheltered entrance space. The overhanging first floor is supported by a row of slender white columns that angle out like tree branches, reinforcing the treehouse analogy.

"This is the edge of a forest where parents can shelter waiting for their children to go out of school," D'Houndt said.

The main dining room is located on the first floor. It has various entrances, allowing different routes in for nursery school students, elementary school pupils and other visitors.

For the kindergarteners, a corridor leads directly though to the hall, meaning they don't have do go outside. School pupils use a staircase that leads directly up from the playground, plus there's also a route straight from the entrance lobby.

Some wall surfaces inside the space are coated with plaster and painted white, while others match the exterior. A series of square windows allow plenty of daylight into the space.

"To gain fluency, the junctions between the different surfaces are gummed: no joints, foot barriers, or links, which are elements into which the mind bumps," said D'Houndt.

"The continuous surfaces, the smooth transitions, and the lack of angles, aim to create more freedom. No limits to the imagination."

Kitchen and bathroom facilities are also located on this floor, while the ground floor accommodates a series of flexible spaces for education and other activities.

Photography is by Julien Lanoo.

Project credits:

Client: Ville de Tourcoing
Architect: D'Houndt+Bajart Architectes & Associés
Engineer: KHEOPS Ingénierie
M&E: BET fluides et Électricité
Graphics: Brokovich