The final piece of the jigsaw
The authorities’ bold decision to build a new kindergarten and primary school in the heart of Montrottier was a result of their desire to give this medieval village a new lease of life, and to recentre its development. Key to the success of the venture was the availability of a site which, though steeply sloping (with a 9 m difference in height between the upper and lower boundaries), was the right size, and also close to the crèche, library and cinema.
Seen from the surrounding undulating landscape, the new building embraces the slope, and is integrated into the general silhouette of the hilltop bastion. It adds to the overall morphological unity, and notably the density of the ensemble, while also affirming its contemporary character with a distinctive wooden form in a granite setting. The separation of the complex into two blocks (one for the kindergarten, the other for the primary school) is in keeping with the topography. And the classrooms are set above the flat, sheltered playgrounds in such a way that the landscape enters into them, so to speak, with spectacular views off into the distance.
The project was enthusiastically backed by the authorities. It can boast of advanced environmental features, like all of Tekhnê’s designs, and does not rely on ostentatious effects.
There is a long, narrow profile that follows a north-north-east / south-south-west axis, with a north-facing slope. The dominant winds are cool and westerly, and there is a favourable orientation in relation to the sun. The utilisation of the outside spaces has been optimised. The complex fits in closely with the nature of the site and its contours. The facades of its 2 rectangular sections, though not exactly parallel, face broadly south-east and north-west. They are unfussy in the way they perform their functions.
The view of Bernard Chaverot, the mayor of Montrottier
As the mayor of the village since 2001, Bernard Chaverot, himself a former teacher, has made this the flagship project of his term of office. «We’ve worked with the parents and taken our time.» This was the case right from the outset, with visits to numerous other buildings that provided the information necessary to fine-tune the specifications. «It’s a compilation of other people’s ideas!» Mr Chaverot is an advocate of bioclimatic design and renewable energy. In the light of a feasibility study carried out by CAUE 69 (the Rhône department’s architectural, planning and environmental body), his view was that the project should occupy an available site in the centre of the village. And it was generally agreed that it should help to create a genuine public square. At the end of the tendering process, a process of dialogue was set up with Tekhnê.
The general concept is that of a sober, low-consumption building, with the utilisation of rainwater, heating provided by a wood-burning boiler rather than an energy-hungry gas-fired boiler, and photovoltaic panels. Apart from the building, traffic and deliveries were sensitive subjects. And Bernard Chaverot took the view that «while the car should have its place, it should not take up all the available space». And cars are indeed in the background, under the trees. Among the most successful aspects of the project are those of «non-noise» (which is generally difficult to achieve in places with concentrations of small children), the large amount of natural light taken in, and minimal energy wastage.
In order to raise the kindergarten to the level of the square, a base was constructed on Chemin de Gouttevine. It includes a municipal car park, which also makes a financial contribution to the operation. The primary school is constructed on 2 levels, with superimposed walkways that allow the passage of air and light in both summer and winter.
The classrooms make use of the incident sunlight, while benefitting from the calm of the surrounding farms and forests, and also avoiding the risk of overheating. A glazed gallery offers views from the entrance to the complex on the square, and links up the 2 sections of the complex, notably with the shared lobby on the northern side of the primary school. In order to give the project the desired visibility, the kindergarten playground and the gable of the multi-purpose space were incorporated into the square.
A substructure in reinforced concrete, a superstructure in wood The base of the project is in reinforced concrete, and it is integrated into the adjoining walls and flights of steps. Above it, the frames, facings and roof structure are in wood. The passageways, which also contribute to the thermal properties, illumination and acoustics of the classrooms and workshops, rise up above the northern side of the complex. Their inclined roofs are equipped with photovoltaic panels that offset some of the overall energy consumption.
The sunlit facades have large bay windows in a varied configuration, integrated into the regular pattern of the wood frame and the horizontal weatherboarding. Some of them are fitted with fixed horizontal slats, or screens that modulate the temperature inside the passageways as well as the illumination and the thermal conditions. The fronts of the classrooms, with their salient surrounding frames, have floor-to-ceiling and double-pane windows that alternate with vertical weatherboarding.
High-performance environmental equipment
The energy consumption of the complex is governed by a combination of 3 principles: bioclimatics, efficiency and renewable energy. The calculated energy consumption is 65% below the reference CEP, in line with the BBC and RT2005 sustainability norms. In terms of energy savings, there is a high level of insulation, and draughtproofing. The outer walls are 25 cm thick, the roof 24 cm.
As far as efficiency is concerned, the double-flow ventilation plays a major role.
- In winter, the air is initially warmed by the sun in the southern-facing passageways, and when extracted, the heat is transferred by a double-flow system to the air that is being introduced into the classrooms. The recovery rate is such that it covers the heating needs almost entirely. The remainder comes from a low-temperature under-floor heating system.
- If the outside temperature permits, the windows can be opened for ventilation purposes. A CO2 sensor and LEDs give information about air quality in the classrooms. When the windows are open, the ventilation system shuts down. Members of staff are expected to be aware of energy-saving (and thus money-saving) considerations.
- In summer, cooling is facilitated by the altitude of the village. At night, air sweeps through the classrooms and is evacuated naturally via the skylights in the passageways, which are controlled automatically.
Then there is the question of renewable energy. The wood-burning boiler in the lower level provides heating not just for the school but also for the neighbouring cultural centre, with its crèche, library and seniors’ club. The roof has 314 m2 of photovoltaic installations that produce 39,440 kWh, which is twice the complex’s electrical consumption.
Apart from energy…
The wellbeing of the occupants has been given particular attention. The complex is bathed in sunlight, though without any dazzle. The classrooms receive light from the north. Hushed tones dominate the classrooms and the passageways. The materials were chosen for their environmental properties, with minimal amounts of volatile organic compounds, but also for their advantages in terms of acoustics and maintenance. The same linoleum is used for the classrooms and the passageways. All the paint, glues and insulating material comply with European Ecolabel norms.
Special care was taken with the choice of wood, where possible using locally-sourced Douglas pine from the Jura, and untreated wood for the interiors. There is a tank for the storage of rainwater, which is used for sanitary purposes, and for watering the vegetable garden. The roofs are planted with sedum, which helps to slow down runoff. And the permeable soil round the building has been stabilised.
The project complies with a «low-pollution» charter which was drawn up by the design team and is contractually binding. Though the invitation to tender was Europe-wide, most of the companies selected are based within 100 km of Montrottier. And the one that supplied the wood frames is situated on the outskirts of the village. The range of products available in the Monts du Lyonnais region, where Montrottier is situated, helped to cut down the ecological footprint of the operation.