LAN completes monolithic minimum security prison in nanterre, france

paris-based architecture firm LAN has completed minimum security prison (see previous coverage here) in nanterre, france, housing, in an unprecedented combination, two different programs: a CSL (center for parole) and SPIP (prison service and probation). located in a very diverse urban area, surrounded by single-family homes and certain industrial buildings, the project aims to reevaluate the relationship between the city and prison boundaries, and decrease the disconnection between the two. its monolithic, cuboid exterior, clad in self-weathering steel sheets, creates a strong, cohesive identity for the building, where the only irregularity in the composition of the volume is a large opening on the south façade that serves as the entry to the minimum-security area.all images © cyrille weiner unless stated otherwise

‘over time, prisons have become “non- urban” objects, or objects “outside the urban sphere”, even when they are built in city centers,’ explains LAN. ‘often encased by a protective wall enclosing one or more buildings within, penitentiary architecture has reduced the field of action to addressing the boundary between the inside and the outside, as well as to the question of control and surveillance.’ seeking to decrease the disconnect between city and prison boundaries, the architects have adapted a series of techniques that relate the design of the building to the city, such as: using a façade instead of a blank wall; creating a more fluid transition between the interior and exterior; and ensuring distribution of volume that links the various scales. from the outside, the building looks like a compact cuboid on the corner shared by the two streets

the nanterre project is unique in that it combines two programs, each of which houses different target populations. the headquarters of the penitentiary services for integration and probation of hauts-de seine [services pénitentiaires d’insertion et de probation des hauts-de-seine (SPIP)] monitors people under arrest, while the ‘minimum security area’ allows convicted offenders to enroll in a unique detention program that lets them leave the penitentiary to participate in a reintegration project, hopefully decreasing repeat offenses. built in an L-shape, the volume composition of each building complements the another, with the SPIP program located at the front, while the semi-open detention area placed within the center block.the entry to the minimum-security area on the south façade creates a large opening in the monolith structure

the building’s compact cuboid form is encased in perforated panels of self-weathering steel sheets, which serve as a visual filter, provide sun protection, and offer a play of overlaps, depth, and transparency. the panels open out thanks to a system of pivoting automated shutters. in direct contact with the prisoner area, the minimum-security area façades, which are located within the center block, are made of robust, waterproof, and self-cleaning materials in thermo-lacquered aluminum and plaster. the light shade of these facades ensures light flows throughout the inside of the building.the minimum-security area has 89 cells, housing 92 prisoners a wide overhang runs above an outdoor space, forming a more fluid, yet secure kind of transition areaperforated panels of self-weathering steel sheets encase the prison buildingthe panels serve as a visual filter, provide sun protection, and offer a play of overlaps, depth, and transparencythey open out thanks to a system of pivoting automated shutters confined within the center block, within the prisoners’ area, the courtyard is accessible from the monitored reception area

image © charly broyez the open, natural space is equipped with basketball and handball courts, where floor treatments are colour-coded with a flat finishlandscaped plots serve to ensure that the plot of land stays moist, while providing a green area in view of the prisoners the cells are accessed from broad walkways and overlook either the courtyard or the planted gardens

image © charly broyez a vegetable garden has even been considered to supplement these green areas, to be managed by and for the prisoners

image © charly broyez site plan detail drawing of the steel façade

project info:

architect: LAN

program: minimum-security area and penitentiary services for integration and probation

client: ministère de la justice, agence publique pour l’immobilier de la justice (apij)

location: nanterre (92), france

cost: 13 m.€ ht

surface: 4 350 sqm

team: LAN (general contractor), franck boutté consultants (HQE), batiserf ingénierie (structure), nicolas ingénierie (liquids, electricity), michel forgue (economist)