• Building Type : Other building
  • Construction Year : 2011
  • Delivery year : 2012
  • Address 1 - street : Place la Paix 30430 SAINT PRIVAT DE CHAMPCLOS, France
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 57 m2
  • Construction/refurbishment cost : 67 000 €
  • Number of none : 1 none
  • Cost/m2 : 1175.44 €/m2

Certifications :

  • Primary energy need
    12 kWhep/m2.an
    (Calculation method : RT 2012 )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building

On the town hall square called "De la Paix" and requalified within the framework of this project, the tourist office is sheltered by a vegetated geodesic dome made of a framework of Anduze bamboos. This former parking in two layers, has been transformed into a real "field-closed" typical of the town, surrounded by mulberry trees (the golden tree) and planted with a meadow of grasses, at the edge, is the evocation of a capital that houses the office.

A "showcase" architecture that draws on the typical vocabulary of local vernacular architecture with its round dry stone capitelles, which are here reinterpreted in an innovative and contemporary technology with local, bio-sourced, renewable materials.


Recycle endlessly with the precepts of « Cradle to Cradle » (C2C)

All the components of this tourist office, which can be completely dismantled, are recyclable and reusable. The steel "nodes" were made specifically for this project by the Thyssen Group. A framework of Anduze bamboos is connected to these "nodes" to which OSB panels are bolted and contain a row of wood fiber between two fire-treated OSB walls. A bio-compatible rubber membrane ensures watertightness. The local chestnut and Douglas fir wood used in the flooring is local and comes from France, its exploitation participates in the sustainable management and maintenance of our forests in the Cevennes. The wood used comes from neighboring forests located within a perimeter of less than 50kms. An entirely natural and non-aggressive treatment for the environment and man allows a dimensional stabilization of the wood while increasing its durability over time. Developed and patented by CIRAD, the process consists, in a first step, in soaking the wood in a bath of vegetable oil heated to 110-200°C, which will then be transferred to a second tank of linseed oil at 60°C.


Plant architecture

An architecture mainly composed of inert vegetable matter for its structure and its insulation and living for its facing. The skin of this living architecture is planted with about fifty species and varieties of perennial Mediterranean plants that are naturally resistant to drought and wind. It is the creation of a real biotope in constant movement (seasonal aspect, colors...) living showcase of the local plant heritage highlighting the flora and biodiversity that hikers and tourists will then discover. This « vegetated biodome » employs an innovative cultivation process that uses a plant substrate, sphagnum moss, which is highly hydro-retaining and saves water for watering.  The « mantle » that this vegetation constitutes is a plus for the thermal balance for this so-called "passive" building. It is the creation of a real biotope in constant movement (seasonal aspect, colors...). 


Autonomous architecture

Although connected to the traditional water supply networks, this building is energy and water efficient and could easily function autonomously.

  • Universal accessibility : the entire project is designed to be accessible to all, both from the user's and the staff's side.
  • Positive energy : this building is wrapped in a mattress of wood fiber and sphagnum moss with a total thickness of 300 mm. It falls into the BBC category of buildings that require less than 12 kWh/year/m².
  • The circadian lighting is provided 24/24h by diodes controlled by a sensor of luminosity and changes color temperature and intensity according to the hours of the day. The total consumption of this building does not exceed 500 Wh in peak which could even be produced by domestic wind turbine !
  • The trombe wall that surrounds the building is made of "dry" stones taken from the territory of the commune, this base is useful because it captures the low rays of the winter sun and remains protected from the vertical summer sun by the plants above.
  • The glazing of the large bay window facing south is protected from the zenithal sun by a plant cap during the summer, and captures the low winter sun.
  • The water for the irrigation and the toilets comes from an old buried cistern made of traditional stones which collects the rainwater of the town hall and which was found during the construction work.

The price of this construction, which brought together 17 companies under public contract, was less than 1200 € excl. taxes per m² of floor space.

Building users opinion

The tourist office, by its notoriety, exceeded by far the limits of the intercommunality. Its transcription by the press (Le Moniteur, Midi Libre, Dauphiné Libéré, Habitat Naturel, La Marseillaise) and television (France 3 program "les architectures végétales") has enabled the municipality to get people to talk about it and to boost its tourism offer based on the values of sustainable development, universal accessibility and enhancement of local heritage for a price lower than that of a conventional building.

If you had to do it again?

This project is called to be repeated and in different sizes since this operation in public market (and certified by a technical controller) made it possible to validate the technology used to go up to 20 meters in diameter.

Photo credit

Jean François Daures. / Nic Geraerdt


Construction Manager


    Structures calculist

    BAST engineers

    Bruno Deraerdt


    Structural study on the building, study for wind resistance

    Certification company


    Etienne Mignard


    Mission of regulatory technical control and SPS

Type of market

Global performance contract

Energy consumption

  • 12,00 kWhep/m2.an
  • 45,00 kWhep/m2.an
  • RT 2012

    No heating needs, only lighting and the operation of a multimedia terminal is necessary, the maximum consumption of the building is 500Wh/c.

Real final energy consumption

    12,00 kWhef/m2.an

    12,00 kWhef/m2.an

    2 011

Envelope performance

    1 OSB sail 27mm
    1 layer of wood fiber 140 mm
    1 OSB sail 27mm
    1 EPDM diaphragm
    1 layer of fresh sphinge 180 mm

    Report of the town hall of St Privat on the entire ten-year period:

    The hostess present in the premises declares that she is not aware of the triggering of the artificial lighting which is controlled by means of a light sensor linked to a capacitor. The smell of wood and the acoustic and visual comfort improve working conditions.

    The public received in the establishment informs a guest book in a very positive way on the general quality of the welcome.

    The vice-president of the General Council of Gard decided, in view of the performance of the building and the satisfaction of the public received, to requalify this Point Info Toursime (PIT) as an Intercommunal Tourist Office (OIT) in 2013.

    The building is not heated, not air-conditioned, however the interior temperature was +17°C with -11°C outside and +27°C with +39°C outside (maximum readings over the ten-year period).

More information

The quality of the envelope, the good exposure of the glass walls, and the care given to the whole made it possible to dispense completely with heating and air conditioning. Actual temperature readings in the building : - Winter - 11°C windy (02/2013). Indoor +17°C - Summer +39°C windy (08/2019). Indoor +27°C


    • No heating system
    • No domestic hot water system
    • No cooling system
    • Natural ventilation
    • humidity sensitive Air Handling Unit (hygro A
    • No renewable energy systems

    The concept was to work without heating as it was a tourist office closed to the public from November to March.

    - La qualité de l'enveloppe qui intègre un mur trombe en pierre sèches en partie basse exposée au soleil d'hiver et une végétalisation de toiture sur toute les autres parties du bâtiment exposées au soleil d'été.
    - La forme hémisphérique qui n'oppose aucune résistance aux vents.
    - La bonne dispositions des baies vitrées qui captent le soleil bas d'hiver et sont protégées du soleil zénithal l'été, grâce à une casquette débordante.

Smart Building

    A telematic information terminal glued to the window allows tourists to get information and to geo-locate the lodgings on the territory of the commune 24/7.


    • Flooding/Runoff
    • Snow weight
    • Urban heat island

    Thanks to its hydro-absorbent vegetable skin, the building is capable of absorbing 200 liters / m² on average during violent rainy episodes called "Cevenols". Designed in 2010 and built in 2011, there were not yet the current certifications allowing a control office to produce the calculation notes.

Urban environment

  • 500,00 m2
  • 57,00 %
  • 400,00
  • Located on the old paved parking lot of the Town Hall, the project proposes the renaturation of the place by its transformation into a landscape, a true evocation of the field-closed typical of the commune, where crops of grasses are surrounded by walls and stone capitelles. dried and planted around mulberry useful for serisiculture.


Construction and exploitation costs

  • 13 000
  • 80 000
  • 30 000
  • Public building co-financed by the LAG.

Energy bill

  • 150,00

Reuse : same function or different function

    • Indoor joineries
    • Partitions
    • others...

    The furniture of the tourist office (10m linear displays, reception desk, tables) was entirely made thanks to the reuse of wood scraps used for the floor.

    The partitions and interior joinery were made with salvaged wood from the dismantling of exhibition stands.

Environmental assessment

    Beyond the zero environmental impact of the project, an existing parking lot was deconstructed in bi-layer goudorn, which was stripped and then replaced by topsoil to create an evocation of the enclosed fields typical of the town.

    To date, the candidate has not provided the information needed to carry out the environmental assessment of the project using the calculation tool.

Economic assessment

  • 13 400
  • 20 %
  • 12 000

Water management

  • 15,00 m3
  • On the occasion of the construction site, an old cistern in freestone entered and forgotten was found under the town hall square. It was put back into service during the project and a lifting pump uses the water to irrigate the building and its surroundings, as well as the sanitary facilities inside the building.

Indoor Air quality

    Only natural ventilation is provided.

    A VMC Hygro B is installed for the toilets.


    A very positive opinion from the hostesses in charge of the reception who declare "not to see the time passing".

Life Cycle Analysis

    This project follows exchanges in 2010 with the chemist Michael Baubgardt who was looking for examples of buildings built on the principle of "cradle to cradle". At that time, C2C referencing did not yet exist.

    The entire building (except the support slab, the dry stone facing and the bay windows) is made of materials from elements of the plant kingdom in their inert (structure) or living (facing) form.

    Wood fiber insulation, and expanded soy foam (fittings).

    Bamboo structure and OSB sails.

    Sphagnum vegetable skin planted with local plants in their wild form (no horticultural cultivars).

Reasons for participating in the competition(s)

This prototype building with the status of an establishment open to the public and workers, built under a public contract, made it possible to validate, with the help of the University of Gent in Belgium, and CIRAD in France, a new construction process based on of a two-dimensional bamboo frame. Thanks to resistance tests carried out in the laboratory on the bamboos themselves and in-situ, on the building afterwards with SOCOTEC (compression, torsion, traction, resistance to winds, fire), it is now possible to make green domes. in diameter up to 20 meters and therefore to cover more than 300m² without any bearing points.

2014 Finalist of the prize of the Occitanie order of architects (modest architecture)

2015 "OFF du développement durable" (sustainable development related contest)

 building biodiversity revegetation circular economy resilience materials and solutions reuse waste recycling Circular Buildings Trophies 2022 Resilient Buildings Trophies 2022

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Author of the page
Jean-François Daures

Architecte DPLG

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