Vertbois Building | Moussafir Architectes + Inside Outside Architecture

Vertbois Building, Restructuring a modern building in the Haut Marais. This 10-level commercial building designed in the 1970s by the Biro Fernier firm is a rare example in this sector of France’s 30-year post-war economic boom. It is comprised of a 7-story reinforced concrete framework on top of a 3-level underground car park built with prestressed concrete technology – innovative for the period – an inverted vault supporting a suspended garden in the heart of the city block and a Mansard roof profile with 6 lucarnes crowning the building, the entire structure is made of shuttered concrete.

Although standing amidst a landmarked district composed entirely of protected historic buildings, local authorities (the ABF) determined that it had no heritage interest, thereby facilitating the transformation of both the interior distribution and its envelope.

A neutral and generic structure. Like open-plan floors without intermediate columns, the principal quality of the original construction resided in its neutral and generic character. This overall grasp of the building’s structure-guided our architectural choice, from the insertion of interior elements (staircases, guardrails, floor, and ceiling coverings) to the design of the envelope by way of the choice of materials and the details regarding their implementation.

Thus, the staircases and guardrails, as well as the façades, were designed as features borrowed from locksmithing, most often suspended and dissociated from the concrete structure in order to highlight the loadbearing role of the original shell in relation to these “borrowed” features.

Flats like offices. Like the façade on the street, which has a pitch of 1m36, and the façade on the garden, which is 10 meters long and has no intermediate load-bearing structure, the rationality of the pillar and beam system enabled the transition from a single-purpose to a mixed-use building superimposing housing with offices. Our decision to expose the structure provided the incentive to not differentiate the dwelling spaces from the offices and to design the flats like offices.

Modernist principles and brutalist aesthetics. In addition to demonstrating the multi-purpose aspect of an ordinary structure, our aim was to assert the relevance of the building’s modernist principles (open plans, grid, and façade open to the north, ribbon windows to the south) and to highlight its brutalist aesthetic by enhancing its materiality.

Project Info
Architects: Moussafir Architectes
Country: France, Paris
Area: 1134 m²
Year: 2023
Photographs: Vincent Leroux, Hervé Abbadie
Project Team: Jacques Moussafir with Virginie Prié, Estelle Grange-Dubellé, Pierrick Fromentin, Mélanie Hébrard and José-Maria Goncalves
Fluid Engineering: Louis Choulet (with Thibault Charles)
Structure Construction: Lisandre
Structural Engineering: Malishev-Wilson
Electricity: Rok
Locksmiths: Kozac
Carpentry: Tischlerei Bereuter
Lifts: Oleolift
Exterior Curtains: Lenco