Decarbonized off-site construction: Spurgin and the Sartrouville School City

The genesis

This major project is the result of an investment of 80 million euros, 34% of which is financed by the municipality and 66% by the department. As part of an urban renewal operation, the Yvelines Departmental Council (CD78) and the City of Sartrouville had launched a Global Public Procurement in 2021 for the construction of a school complex with a capacity of 1200 students. The future School Complex is spread over a plot of approximately 30.000 m² where the former Gally greenhouse garden center and the Jacques Prévert nursery school were located at the northwest corner, as well as a wasteland area at the southwest corner. The project was carried out in two separate phases.

The first concerns the demolition of all existing buildings except the Jacques Prévert nursery school and the construction of all the buildings of the school complex except the elementary school: middle school, nursery school, amphitheater, leisure center without accommodation, CDI, Language Center, half-board, sports center). The second stage concerns the demolition of the nursery school and the creation of the elementary school.

The actors

Jointly supported by the Yvelines department, which is responsible for project management, and the municipality of Sartrouville, this emblematic reference is the result of the collaboration of two architectural firms: Officina and Gianni Ranaulo Design.

It is carried out by GCC Equipements publics IDF and Léon Grosse Construction with the contribution of renowned design offices (Gally, EODD, INCET, MaP3, Batiss, Ginger DELEO, Sémofi, ARWYTEC, ALTIA) and the economist CYPRIUM.

Project

Ultimately, the school complex will include a 9-class nursery school (replacing the current Jacques Prévert school, with a capacity of 300 children), a leisure center without accommodation for nursery school children, an 11-class elementary school (300 students), a 20-class middle school (replacing the Romain Rolland middle school, with a capacity of 600 students), a language learning center (open to external stakeholders outside school hours), a shared teachers' room, school canteens for all levels, a gymnasium and several sports facilities, an Information and Documentation Center (CDI) as well as an amphitheater, staff housing and parking spaces.

With a surface area of ​​14.514 m² (9.500 m² of ground area), the future school city of Sartrouville will have in particular the labels and E3C1 certification (targeted incorporation rate of bio-sourced material of 36 kg/m² sdp), Level 3 biosourced, HQE, RE2020. It thus uses biosourced materials that meet the highest requirements, both environmental and energy (energy commitment of consumption less than 50 kWh final/m² (Subtle).

In addition to the installation of a photovoltaic panel park covering a quarter of electricity consumption, heat production will be carried out using a biomass boiler room with a power of 2 MW (coupled with production with gas backup). The city will also integrate air treatment plants.^* with high-efficiency plate heat recovery units, as well as a 7.550 mXNUMX green roof terrace² and will have optimal management of rainwater.

* The presence of plate heat recovery units on the CTAs also ensures that in the toilets and rooms with specific pollution, not the VMC (energy-intensive system in winter), but the recovery via the CTAs which allows the energy from this extracted air to be recovered for the benefit of the fresh air), and indirect adiabatic cooling modules. Indirect adiabatic cooling guarantees, without significant investment and in a simple and passive way, summer comfort for all connected rooms. It is a virtuous system meeting a need for comfort without harming environmental ambitions.

A response to the legitimate requests of the Department and the Municipality of Sartrouville

Beyond the architectural aspect, let us mention that the Cité Scolaire de Sartrouville meets a dual objective. The first, educational, naturally consists of ensuring the academic success of students. The future school city is in fact designed as a teaching unit ensuring a coherent transition between school and college. In addition, the future establishment is designed as a living space encouraging the extension of the time spent by students and adults in order to allow learning outside of school hours. The strategy, beyond the quality of future facilities, will be to ensure English bilingualism for 100% of students at the end of the 3^nd as well as a close link with the neighboring National Drama Center, to offer learning bridges. The second objective, territorial, aims to ensure more social diversity. Indeed, the city is facing a growing demand for schooling from families from international mobility. It is in this sense, but also to strengthen social diversity and the attractiveness of public facilities, that the college will be resolutely turned towards the international, with a strong linguistic dimension.

A bioclimatic architectural design that fits perfectly into its environment

Let us specify that the architectural design is based on 3 founding principles: the interaction between architecture and landscape, organic architecture and architecture as a support for the development of the child's body. It also reflects the desire to build a building that demonstrates performance and respects its environment and the existing landscape. According to the architects, " One of the major challenges was to find the best possible integration of this vast project into its immediate environment (while preserving the existing topology as much as possible) consisting of recreational, sports and cultural sites (Poney-club and Théâtre National de Sartrouville), two types of residential neighborhoods (pavilion to the southwest and collective housing buildings to the north), as well as an urban planning project to the east devoted to the future SNCF train station. The college and nursery school buildings fold in on themselves and their respective courtyards, like shells. This creates a protective morphology for the classes and courtyards in relation to the environment that surrounds them. The same principle is partially applied for the elementary school section, in order to preserve the existing grove of remarkable trees, on the rue de thann side, which will eventually be integrated into the elementary courtyard. The cohesion of the buildings of the Cité Scolaire is possible thanks to the Canopée. The Canopy is a covering structure that links the three establishments, concentrating the different pedestrian flows in order to guide them through the space. Parts of the Canopy are completely covered to shelter from the rain, this concerns the courtyard areas of the elementary and middle schools, located at the ends of its route. The horizontal blades of the Canopy and the vertical ones of the facades give an architectural unity and a rhythm to the project in order to create a common identity.

This mixture of straight and twisted lines at the entrances, as well as the curves in the facades or plans, create a dynamic of movement that improves the integration into the site. In addition, the omnipresent landscaping treatment in this achievement creates the unifying link in the middle of places of exchange and socialization. The landscape is embodied both in the courtyards (where the intimate form and the layout were designed to invite and allow children to also practice calm activities in relaxation) as well as on the roof terraces (as supports for vegetation) and the sequences of entrances to the forecourts. »

And to conclude on the treatment of the facades: “ The project is part of a qualitative architectural approach based on simplicity in the choice of materiality, reducing its facades to the repetition of a vertical element and the refined treatment of its flat surface. This allows a controlled implementation, focused on the good management of details and finishes. »

SPURGIN's low-carbon contribution to the Sartrouville School City

Spurgin offers a complete range of wood concrete products. 24 and 30 cm load-bearing walls, FP2 and FP3 facade panels and slabs constitute the current offer.

The Spurgin wood concrete load-bearing wall solution implemented on this reference of the Sartrouville School City, is structural, low carbon and bio-sourced. It stands out for its technical and environmental performance thanks to a plurality of assets.

Produced industrially and to measure, it is manufactured in the recent Spurgin factory in Mignières (28) and delivered “just in time” to perfectly adapt to the schedule of a fast-paced construction site.

Improving safety on site through simple implementation, it also ensures a reduction in equipment costs, as well as deadlines and therefore execution costs, not to mention significantly less arduousness.

It also proves to be a guarantee of excellent finishes and ease of operation thanks to facings adapted to the second work. If the Spurgin wood concrete solution does not move over time and does not swell, it is perfectly resistant to mechanical variations, fire (2 hours) as well as wood-eating insects and fungi.

Constituting a complete system, the Spurgin wood concrete response claims a thermal phase shift performance of up to 17 hours in 30 cm thickness. Maintaining a low and constant interior temperature in summer, it breathes by naturally allowing water vapor to pass through, a real guarantee of constant humidity preventing condensation and drying out of the air. In addition, in a complex treated according to our simple recommendations, it allows external sounds to be attenuated beyond the standard in force (up to 62 db) and absorbs interior sounds for increased acoustic quality.

A complete response to RE2020, the Spurgin wood concrete load-bearing wall, available in 24 and 30 cm, claims a negative carbon footprint (-11,4 kg CO₂ eq/m² 24 cm thick and -17,1 kg CO₂ eq/m² in 30 cm thickness) with up to 55 kg of bio-based material per m² (under CCB Greentech License – TimberROC process, FDES amendment A1 modules A to C). Finally, let us specify that the wood aggregates used in the formulation of Spurgin wood concrete come from crushed wood from French forests labeled “bois de France”.