en.Wedoany.com Reported - The new cellar of Domaine Nebout, located on the edge of Saint-Pourçain-sur-Sioule in the Allier department of France, stands out with its distinctive circular shape. Designed by Charles Coulanjon of Alice Architecture, this single-story building covers 2,000 square meters and is used for the production and sale of organic wines from the eponymous estate. It also houses a local product shop and a multifunctional hall with a capacity of 150 people. The project combines BIM design, bio-based materials, and industrialized off-site solutions using Activ'Home wood-straw modular panels.

The project was initiated by the Nebout couple, owners of the estate, who sought assistance from the Central Mountain Wine Region Association (TVMC). TVMC invited Alice Architecture to participate. Architect Charles Coulanjon led the collaborative process between the client, architects, and craftsmen through a digital model (BIM). He believes this collaborative approach allowed for the integration of bio-based design, technical complexity, and high energy efficiency without exceeding the €1.8 million budget. The synergy of skills brought significant added value in cost optimization, expanding the project from an initial rectangular cladding building to one that fulfilled all the client's wishes.

The architect prioritized bio-based materials, using concrete only for the foundations and floor slab. The thermal efficiency of the wood-straw construction solution was so effective that after the building was sealed, the craftsmen abandoned their temporary site huts and moved into the building. The compressed straw modules perform well in terms of fire safety and do not attract rodents. The ambition for ecological design and low-energy construction aligns with the Nebout couple's vision. They wanted the project to harmonize with vineyard work, be rooted in the local area, and use simple, natural, local materials such as wood, straw, and stone.

The building's circular facade, with a diameter of 44 meters, is composed of simple structural elements. The wall is divided into small facets 2.40 meters wide, twice the width of the 1.20-meter Activ'Home wood-straw panels, to avoid waste and facilitate construction. The wall height varies between 7 and 8 meters due to the sloping roof. To simplify manufacturing, the lower part of the wall is standardized at 5.60 meters high, while the top is handled with custom panels. To ensure facade stability and resist wind loads, glued laminated timber vertical members are integrated into the full-height walls.

The wood-straw wall area totals 871 square meters. These structural modules are produced in a short supply chain using the patented Ecostrauv process, manufactured by Activ'Home at its new factory in Reugny (Allier department), 60 kilometers from the construction site. The straw used in the modules comes from the neighboring Limagne region. Activ'Home wood-straw modules serve simultaneously as the frame and insulation material, with a light weight of approximately 100 kg/m². They can be used as load-bearing walls for buildings up to R+2, or higher if used as cladding for steel structures, and are also suitable for floors. This material meets RE2020 requirements, can achieve E+C- certification, offers a thermal phase shift of up to 17 hours, a thermal resistance R-value of up to 7.5 m².K/W, and an estimated carbon storage of 10 kg per square meter of panel.

The remaining facades, which wrap around the reception tower, shop, multifunctional hall, and aging cellar, are built with natural stone from Provence. A total of 196 stone blocks, each weighing 2 tons, are arranged in an interlocking pattern without cutting. The roof, oriented due south, is equipped with 1,800 square meters of photovoltaic panels, providing energy self-sufficiency equivalent to the consumption of 50 households. For the architect, this large-scale bio-based project is a first step toward popularizing wood-straw materials. This comprehensive construction method, which pursues energy self-sufficiency, is applicable to all types of buildings, from single-family homes to industrial structures. To achieve unparalleled comfort, the cost is approximately €1,000 per square meter, €200/m² more than traditional concrete block construction.