Author(s): Bourbouze & Graindorge
Contributor: Frédéric Bonnet Obras, Collectif AJAP14

Unbeknownst to themselves: housing!


July 2015. Perched on his terrace on the second floor of the Résidence La Palombière at Montoir-de-Bretagne, temping labourer at the chantiers  de l’Atlantique STX France, enjoyed a forced rest. A warehouseman in a shipyard, he is off work and rests his back. He moved  into the freshly delivered  social housing project with his family a few weeks ago. In the building across, other tenants enjoy the warm sunlight and set up paddling pads for their toddlers  on their loggias. The new neighbours exchange knowing glances. Many have finally found a first home after a chaotic residential journey or life accidents.

A few miles from the Saint-Nazaire shipbuilding yards, the territory of the commune of Montoir-de-Bretagne is split up by an industrial estate: the Saint-Nazaire airport, the Cadréan industrial  and commercial estate, the harbour  and a residential  area around old villages. The latter typifies the peri-urban village  near a regional  French  metropolis. To reach the Loire estuary, one must cross the highway, the railway and the Airbus fac- tory that privatised partly  the landing  strip of the airport.  The smells  and silhouettes of the smokestacks recall the proximity of the Donge refinery. A suite of neo-Brittany inspired pavilion is organised  in successive fringes along new paths. All end up in a racket form at the limit between the natural and urban space. Thankfully, the horizon opens up: at the north of the tow, the Brière Natural Regional Park forms an unmovable barrier. This marsh is the second largest in France after the Camargue. The seven inhabited islands of Chaumière made using reeds – a secular local resource – emerge from the huge bog. The theme of the bog, and particularly that of bird shooting – gave its name to the real estate project steered by the social leaser of Saint-Nazaire, Silène Habitat.  The works were entrusted in 2010 to architecture agency Broubouze et Graindorge.


After having practised in several high- profile agencies, Gricha Bourbouze and Cécile Graindorge  found their own agency in Paris in 2005. Whilst professional recognition  and access to commissions proves effortless in the capital city, they move to Nantes to focus on their family life. Used to designing and building housing, each new project  gives them another  opportunity to experiment  construction solutions  allowing a resilience of buildings in time: concrete or metallic structures for infill operations in existing areas; load bearing façades built in the more relaxed context of development zones.

They were very quickly  noticed  by Silène a housing company in charge of selecting the agency participating to the project management competition for the construction of 48 social dwellings in Montoir-de-Bretagne. The agency is the laureate of the competition with a proposition making ambiguous the perception of built volumes, between community and individual housing. “It is important to inscribe ourselves delicately in the urban and symbolic of this location, so we tried to “disturb” usual living modes, and offered some alternatives to excessively individualistic residential habits linked to these territories. The main criticism commonly addressed to the pavilion-style  house is in the erosion of every notion of community.  Therefore, we tried to define the spatial modalities of a joyful cohabitation”.


Over 150 meters long, 30 meters wide plot in a slight slope, Bourbouze and Graindorge affirm their relation to the wide landscape whilst  fabricating an interior  landscape.  A two-rows three-dimensional matrix of the size of large houses lay out in quincunx alternates constructions and non-built areas. Subtle offsets offer a permeability  of the views and courses whilst adapting to the topography. Between the constructions, an interior landscape of paths and gardens exiting on the distribution course are punctuated with a bench and a tree. Around the paving, the eight stairwells  spread out, as well as housing-dedicated services: pocket parking under the buildings, individual  cellars/bike sheds, letter-boxes, and access to the upper floors by opened stairs. On the upper floors, the volumes are pierced with spacious panoramic loggias facing the east, west and south to reach out for the distant views over the rural landscape.

Visiting the place, these fragmented constructions all feel of similar size. Only a small fold on the façade on the fifth and sixth plots marries the traced of a new road of the housing project. Closer still, the long paths give to see a collection of doors, communal areas, parking areas and above our heads fine gateways framing the landscape. The link between the two isolated buildings creates the “good” gap between the edifices. An attentive reading of the plans unveils a catalogue  of typologies with an inventive assemblage: simplex over the garden, duplex and triplex, whilst the first floor is only used as an isolated entrance hall. The various types of distribution enrich the diversity of the dwellings:  individual access to the ground floor, communal access via the stairs, and semi-individual access at the end of the gateway. Here, the architects  experiment a hybrid residential typology  that creates neighbourhood units so dear to Team X4: a collective urban structure with an individual perception.


The organisation  of each house rests on a spatial principle of free platforms allowing a typological freedom and flexibility at long term. The structure is mixed: the load bearing façade is in 25 cm thick monomur bricks, a circulation node in concrete  walls ensures the seismic bracing; the floors are in reinforced concrete stiffened by the raised concrete for the benefit of the loggias. A sole central pole ensures the intermediate fulcrum. This concentric  structural principle thus frees the entire interior  space. The panelling  is free, organised  by the position  of the ducts  leaning on the kitchens  and the proportion of the square or rectangular living room enjoying the largest side on the lit-up façade. By type of plot, plots, the plans of the dwellings, tri- ply or doubly orientated, are completely different on each floor, and deploy  according to the position  of the loggia. These loggias are offset from one level to the next and from one block to another, thus avoiding direct overviews. They are so large – from 10 to 20 square meters depending on the type – that they offer an alternative  exterior circulation from one room to the next.

This seemingly simple principle was not with- out difficulty  to design and realise. The thick 30cm recovery slabs house buried beams, require sufficient metal. The alternation of the many loggias  multiply  the breaks in lowering vertical charges and the surfaces in con- tact with the outside, which are meant to be waterproofed and isolated. The application of energetic labels in force – Effinergie RT2005 and Qualitel – are increasingly  constraining and the recent evolution of a seismic standard in the region contribute to render more complex  the design and implementation of the structure  studied and has impacted  the overall cost of the operation. Moreover, in the aim of responding to the requirements of the couple of Nantes architects, the “French” project management designing method proves problematic. The splitting  of responsibilities between architect,  engineering bureaus and the contractor’s execution offices forbids too much precision in the technical drawings and regulations until the call for tender, whereas this type of project would deserve an in-depth study from the first phases of the operation. Bourbouze and Graindorge doubled their efforts to guarantee the result because, if responsibilities are shared with engineering bureaus  from a contractual viewpoint, the workload isn’t.


The exhaustive  analysis of the distribution of networks characterises this new form of hybrid dwelling between individual and collective.  The distribution of fluids – water, gas, and electricity – is collective for housing situated near the stairwell and individualised with  dedicated cabinets  for the other lodgings. However, each dwelling enjoys a wall mounted gas heater and cast-iron radiators. As simple to use as in a house for tenants, this type of equipment required a complex set up for the supply of gas distribution networks. Here via the floor ducts, there using less conventional paths without going through the neighbour, – in the ceiling, wall, slab then in aerial to reach the kitchens of the dwellings furthest away from the cabinet.

The same attention from architects  is visible for exterior networks: on the walls, floors and fencing,  all the technical  elements  – man- holes, electricity  chamber, gas cabinet, and telecommunications – are integrated.


Here, no wood cladding no colourful composite panel or wooden fencing to announce the new constructions using a façade posting system. In this land of marshes and swamps, the architects  seek the expression of banal built forms, clever balance between archetype  and pavilion-style construction, and poor materials for a sophisticated implementation.  By reinterpreting  the vocabulary of suburbia, the pavilion, the architectural language is voluntarily  neutral to blend into the décor. The project relies on suburban stereotypes  – scale of constructions, formal expression of the house, and place for the car – drawn and amended with great precision. The scale of buildings  corresponds  to that of a large house, a manor, and maintains its domestic  image whilst borrowing  forms and materials to the imaginary of the pavilion: a basic roof and pinion form unclad from its trivial accessories: balconies, ironworks, gutters,  porches…  The work by subtraction of volumes of the loggias, selection of various materials – grey scrapped or coated finish, Lé tiles roofs, glass paste, polycarbonate fencing, crude block  work walls – and a choice restrained to a range of greys feed this  neutrality.  All the constructive details are studied,  with the objective  of a certain abstraction, visual simplicity. However, many required titan efforts to put in place. Their sophistication is harmed by the restrained competences of the companies that own the construction markets. Indeed, construction choices are traditional in the mobilised know-how and forced small local companies used to standardised  dwellings to respond to the call for tender at low cost. Yet the complexity of the project and implementation details goes beyond the apparent  simplicity.  From the inside of dwellings, everything seems oblivious: the entrance hall that directly opens onto the large living room, the relation between kitchen and living room with a large loggia, the bathroom enjoying natural sunlight as often as possible,  the rooms depending from the living room to limit the width of the buildings  and maximise the living area. The link between  the qualities  of the dwelling and generated volume prefigures new urban forms.


Whilst all attention focuses on the pavilion-style  housing development, urban modes conceived like simple products,  and its pavilions chosen from a catalogue,  the moral criticism pains to go beyond the circle of urbanist architects and a handful of enlightened elected officials. To understand the reasons behind its proliferation,  one must try to characterise it: a sort of large flat ensemble with a completely atrophied  urban thought by a fragmented splitting purely geometrical linked to the search for a maximal profit. The new neighbourhood of the Ormois in Montoir-de-Bretagne is implanted  in a landscape boasting spectacular preliminary qualities to its project  implementation. The inhabitants of housing developments and peri-urban areas often mention the landscape quality as the motivation for their settlement. Almost always in this sort of situation, the qualities of the landscape, of the site, in what makes the attraction  disappears  after the completion of the project. If something remains, one turns one’s back to it, as though sparing it from the mediocrity  of the master plans and the houses by masking what, yesterday still, made this place enchanting. This is very much the case here: we border the Brière, one of the most remarkable sites in the region. The site of the Brière is well protected: building on the border means ensuring the continuity  of this landscape for a long time, guaranteeing a magnificent horizon to modest houses, giving them effortlessly the very value that their own configuration would  not attribute them. “Ordinary” houses produced by the pavilion-style architecture turns  its  back to the landscape. The subdivision  plan pretends that this incredible landscape did not exist and the development  could very much be situated  in Lorraine, in the Paris region, around Lyon, above a rock formation or next to a waste plant.

The project  proposed by Bourbouze  and Grandorge remains very modest: standard construction, relatively poor materials. They question the notion of qualitative  density in this context,  used to a too feeble density of individual or semi detached houses. They bring reflection paths on the road of the integrated house naturally integrated to the daily journeys under dwellings. Parking is not shameful or completely  staged, but rather, it is assimilated to an extension of the hallway. The disposition in mass plans is not blind to the landscape:  some transparencies are maintained, views open onto the marsh from the interwoven dwellings. These housing projects acquired  the benefit of an unmovable landscape with great economy.


What  were  the  production conditions for this operation? What financial balance? What cost of the real estate for social housing?  The client, Silène  Habitat,  inherits from 90 years’ experience  in the construction of social housing. Founded in 1924, the low-cost  Public Housing office of the city of Saint-Nazaire  is now attached  to community supervision.  This new action perimeter gives it a great consistency  of action at inter communal scale. The operation is part of the multi-sites ANRU programme.  The demolition of blocks was carried out on same large whole, but the reconstruction of housing was disseminated over several communes.  The splitting of demand  responds  very closely to the pools of jobs and profiles of candidates. Unfortunately, this social requirement favours smaller surfaces. The imbrication  of typologies  with a maximum of small typologies is not easy for a distribution. The choice of this fragmented urban form requires few surfaces per floor, but multiplies their number. Similarly, the lines and surfaces of the façades are very important  in relation to the habitable floor surface. However, the budget did not go over. The permanent presence of operational managers from the start to the end of the studies on the part of the project management, the efficiency of the internal organisation allows to install a relation of trust with the client, perhaps not foreign to the quality of the built project.

At Silène Habitat,  specification sheets are constantly evolving and are not closed. It evokes the needs and does not impose solutions of principle or space organisation. Moreover, to valorise feedback, the leaser organises numerous visits of its operations upon delivery with the elected officials, internal services and the clients to capitalise on the successes,  the failures, and the points for improvement. It is also the occasion  to exchange on the consequences of the application  of future regulatory  constraints that put  a strain  on the development budget. On its part, the SONADEV, an actor of local development at the service of municipalities finances the roads and infrastructure networks  by balancing  its books  by reselling land at market price, including to the leasers. The collaborative spirit  that reigns between all the decision  scales of the local  political life makes possible the construction of an innovative architecture  whilst producing quantity of high quality social housing. Whist the society  demand for architectures is partially absent, whereas from the point of inhabitants  or company  directors,  the fight of Gricha Bourbouze and Cécile Graindorge lies in the difficulty to produce an Architecture with the community housing orders, whether social or private.

- Bourbouze & Graindorge
- Silène
- 48 logements
- Montoir de Bretagne
- 2015
- 4700 m²
- 4.9 M € HT