Rooftop Farm on a Housing Building from the 60's

SOA, Le Sommer, Michel Forgue, Courtirey e.a.


A concept for buildings at ROMAINVILLE  - and elsewhere :

Romainville, on the Seine-Saint-Denis plateau next to Paris, has a complex topography, which during the town’s growth created a series of rifts in the urban landscape.

The Marcel Cachin social housing estate, built in the 1950s, is typical of the large-scale developments at that time. Its long horizontal blocks and several 4 to 8 storey towers are spread over a large surface area. Particularly enclosed by its physiognomy and cut off from the heterogeneous fabric of the old town centre, the Marcel-Cachin estate was rehabilitated for the first time in the 1990s. From 2001, it benefited from an Urban Renewal Operation, subsequently transformed into a National Urban Renovation Agency project, whose aim is to integrate the district into the town centre through architectural, urban and landscaping interventions.

Today, after the estate’s partial demolition, the transformation of its road network and the creation of an open, landscaped central plain, the district now has new (media library and “House of Childhood”) and transformed (retirement homes, local meeting rooms) amenities, vectors of social integration catering for a wide public drawn from all over Romainville.
The creation of residentialisation spaces at the foot of the buildings, the sectioning of several long blocks and the refurbishment of buildings will also profoundly modify the district’s habits, and this will accentuated by the relocation of shops and businesses within it. The automated pneumatic refuse collection system, which began operating in the district in late 2011, affirms the town council’s commitment to sustainable development and innovative means of achieving this.



The project consists of a farm, whose contemporary architecture contrasts with that of the existing housing blocks. It is supported by a portico enveloping the existing building. Yet since this farm is an agricultural structure resembling a traditional greenhouse, its use is clearly recognisable. The project’s aim is to propose a new interpretation of the estate’s housing blocks, the outline of whose additional levels contrasts with the blocks parallelism and horizontality. This is why the farm’s skyline is staggered here and there. Nevertheless, the portico respects the existing architecture and preserves its rhythm and regularity, and the lower part of the building retains its relationship with the district’s other buildings.


The farm is grafted onto buildings Cb, Da and Db. Its programme is divided into three main categories: the growing areas, work areas and technical spaces. The growing and work areas are on the roofs of the existing buildings, above five storeys of apartments. The circulations and technical facilities are at the north end of building Da.


Technical spaces

The farm is accessed on the ground floor, next to its technical areas. The entrance is in building Da, between buildings Cb and Db, opposite the central park area. The farm’s entrance is therefore located on the park’s axis and directly connected to the public amenities surrounding the central park area: the “House of Childhood” and the media library. The wide entrance on the ground floor facilitates manipulation of earth and farming equipment. A lift and a spiral staircase link the farm’s ground-floor and roof areas. The farm’s boiler room, washing facilities and two water storage rooms are in the basement, on the same level as the housing units’ cellars. The earth and waste storage area are on the ground floor, with direct access to the exterior.  

The work areas

The farm is deployed on two levels on the roofs. The work areas are on the roof of building Da, next to the vertical circulations. The lower level houses the cold rooms, transformation and packing areas, stock of consumables and an equipment maintenance space. The upper level houses the seed nursery, dangerous product storage area, beekeeping area, lunch and refreshment space, office and locker room.


Growing areas

The growing areas are divided into three zones in polycarbonate greenhouses, each on the roof of a different building. The greenhouses are lightweight metal pillar and beam constructions. The crops grown, requiring three different climatic environments in winter, produce a variety of vegetables all year round. These greenhouses are therefore heated at different temperatures in winter: 8° C in the greenhouse on the roof of building Cb, 12° C in the greenhouse on building Da, and 18° C in the greenhouse on building Db. All three are linked by grating gangways.

The crops in the greenhouses are grown on two levels, in soil in tubs using the Courtirey system. The dimensions of the tubs and their spacing are calculated to enable light to penetrate without hindering growth. The spaces between the tubs enable the farmer to work and move trolleys along each row. There are enlargements in the alleyways for parking trolleys and keeping equipment. On the farm’s lower level, a filtration greenhouse garden filters the air extracted from the ventilation system of the apartments below.

Each greenhouse has two levels of crops. The upper level is always accessible via the spiral staircase and the lift at the entrance, at the end of building Da. Each greenhouse also has its own staircase to reduce time loss.


The greenhouses’ energy consumption is optimised by a high-performance thermal envelope, mobile sunlight screens, a central computer managing the greenhouses’ energy consumption, interior climate and the different temperatures of each greenhouse, reduction of air infiltrations, rainwater and hot water storage.



Extension of the housing units  

Since the existing building cannot support heavy loads, the farm rests on a concrete portico enveloping the existing façade. This structure also supports concrete slabs that extend each housing unit in the form of balconies and conservatories on either side of the building. The apartments therefore have extensions on both sides, beyond their kitchens and bathrooms on one side, and bedrooms and living rooms on the other. Their large balconies face southeast. The temperate conservatories at the back provide additional storage space for these quite small apartments.  


Farm/housing unit proximity

The cohabitation of a farm and housing units in one building will definitely encourage exchanges between both programmes. The farm recycles the air extracted from the buildings’ ventilation systems, and produces fruits and vegetables that can be consumed on the spot by the buildings’ inhabitants via a sales system yet to be defined (baskets, AMAP, market, etc.)