In this transition to carbon neutrality, synergies are multiplying between players in construction and real estate and those in the wood industry, to echo the commitments of the “Ambition Bois Construction 2030” plan, and in particular to invest in Research & Development, develop the French wood supply and support the economy of the territories. These are the challenges facing Bouygues Bâtiment France Europe, which aims to turn 30% of its structures into wood projects by 2030, and Manubois, a subsidiary of the Lefebvre group, which is renewing wood construction methods with the launch of laminated timber. glued structural beech. The two companies will be experimenting with this technical innovation in summer 2021 on a tertiary project built in Rouen by Bouygues Bâtiment Grand Ouest and developed by the developer Linkcity.
Beech enters the construction market
If wood construction is experiencing strong development, boosted by technical innovations and encouraged by the public authorities, it mainly uses softwoods, generally at lower cost, but which represent less than 30% of French forests and are therefore largely imported. from Northern and Eastern Europe to meet growing demand. However, deciduous woods constitute more than 70% of the French forest area, beech being the second resource after oak. This popular essence in the field of furniture and
interior joinery, is distinguished by a remarkable density and mechanical resistance which suggests good prospects for timber construction.
This is the bet made by Manubois, a subsidiary of the Lefebvre group specializing in the secondary processing of wood, which has been producing finger-jointed glued laminated timber (LCA), mainly in beech, for 30 years. The Norman company launches into the production of glued laminated beech for use in structures. Its industrial processes and tools had to be adapted to the manufacture of large-scale BLCs, for the production of columns and beams. Manubois has obtained the “CTB” certification for glued laminated timber based on beech for use in “structures” issued by the FCBA, which attests to the reliability, quality and performance of this solution. The characterization of the product by the FCBA institute has made it possible to shed light on its mechanical properties - a density and resistance clearly superior to those of softwoods - which make it a sustainable alternative to concrete and metal for heavy loads.
A promising innovation for wood and biobased construction
Apart from the ecological advantages of wood - a natural, renewable and recyclable material coming from the dry sector, and its capacity to store carbon (1 m3 of wood stores around 850 kg of CO2) - this innovation has many advantages for construction. It contributes to the development of French and even local timber: Manubois mainly obtains its supplies from the forests of Seine Maritime, exploiting resources within a radius of around 50 km. It thus promotes short circuits, positively impacting the carbon footprint of its activities. In addition, “with this solution dedicated to construction, we are now using wood that has little or no value, because it has knots for example, and thus contributes to good forest management” underlines Maxime CASTEL, Prescriber of Beech. structural at Manubois.
BLC + Beech is also distinguished by its aesthetic qualities: composed of small slats, it has a very high quality homogeneity and surface appearance, as well as a light and warm color. These qualities, combined with its high resistance, make it possible to use much thinner sections, which constitutes an architectural advantage and offers a valuable gain in floor space in buildings.
This fineness finally generates material savings which, added to a reduced carbon footprint, offset the additional cost of processing compared to that of coniferous species.
A dynamic partnership to accelerate the growth of wood in construction
Committed on a daily basis to building a sustainable living environment, Bouygues Bâtiment France Europe has made wood construction one of its priorities with the objective of turning 30% of its structures into wood projects by 2030. This ambition is illustrated by the WeWood approach and the creation of a wood center of excellence made up of 30 expert engineers offering advice, expertise and training to all of its teams. But also through the partner club and WeWood solutions, to collectively bring out innovations and translate them into projects developed by all its subsidiaries. It is in this logic of co-construction that Bouygues Bâtiment France Europe is supporting Manubois in the development of its BLC + Hêtre innovation.
"Our strategy is pragmatic," explains Fabrice Denis, Director of Wood Construction Strategy - Bouygues Bâtiment France Europe, "Put wood wherever you can, by capitalizing on a center of excellence, the innovative strengths of wood solutions, training and a partner club!" "
A first commercial demonstrator building in Rouen
A first experiment is thus planned in Rouen, as part of an ambitious urban renewal project, that of the “L 'Awakening of Flaubert” district, developed by Linkcity and whose work will be carried out by Bouygues Bâtiment Grand Ouest. This vast mixed and intergenerational operation is also the largest tertiary operation in the metropolis, with two office buildings with a total area of 16 m². A first tertiary building
R + 7, with a floor area of 9 m², should emerge from the ground between March 000 and March 2021 in this district located on the edge of the Seine. About 2023 posts, or 70 m³ of glued laminated beech, will be installed on this building, supporting the concrete floors.
This building, which aims to be exemplary in terms of environmental impact, will reach the BEPOS Effinergie 2017 and E3 level of the E + C- label. It is also aiming for the BBCA label and the BREEAM New Construction 2016 certification, VERY GOOD level. This certification is today the most used in Europe.
The result of a real synergy between the teams of Manubois, Bouygues Bâtiment Grand Ouest, Linkcity and the WeWood pole of expertise, this collaborative project combines low environmental impact and strong local roots: it promotes both innovation and local resources. territory within a pilot operation intended to support the development of a local timber industry and pave the way for new constructive methods.