In Chavannes-près-Renens, in the canton of Vaud, an innovative bu"> In Chavannes-près-Renens, in the canton of Vaud, an innovative bu">

Is green construction more sustainable?

16.05.2024

Is green construction more sustainable?
"La tour des Cèdres" forest building: an ambitious project in Chavannes-près-Renens
In Chavannes-près-Renens, in the canton of Vaud, an innovative building project is arousing both curiosity and scepticism. Designed by renowned Milanese architect Stefano Boeri, the future green tower "La tour des Cèdres" promises to transform the urban landscape with its 152 trees and 252 homes. But this initiative, although a pioneer in Switzerland, raises crucial questions about its sustainability and environmental impact.

Ten years of patience for a public enquiry
The enquiry process for this emblematic tower was completed at the end of April, after more than ten years of administrative procedures and complications. This project, approved by the citizens of Chavannes-près-Renens a decade ago, has not finished making headlines. The green mantle of the building, covering 1293 square metres, is at the centre of the debate. Visitors to the information area, organised by the Orllati Group, oscillate between enthusiasm and scepticism.

Watering and fire hazards: criticisms emerge
Among those opposed to the project, the continuous watering of the trees is a major concern. Bertrand de Rham, a Green local councillor and member of the Bien Vivre à Chavannes association, points out the risks associated with the use of drinking water, particularly in times of drought. Although the project includes a rainwater recovery system, recourse to the local water network is unavoidable if necessary.

Resistant species and increased biodiversity
The Orllati Group website vigorously defends the ecological viability of the tower, stating that the species chosen are adapted to local climatic conditions, hardy and resource-efficient. Sébastien Ohl, Property Director of the Orllati Group, stresses the importance of this greening for biodiversity and the reduction of urban heat islands. What's more, building high up frees up two hectares of land, which will be converted into a public park.

Green towers: a sustainable solution?
Thomas Jusselme, Professor of Energy Efficiency at the Fribourg School of Architecture and Engineering, points out that sustainability in construction is not limited to the fight against global warming. Biodiversity, water resources and greenhouse gas emissions are also key factors. Although the Cèdres tower may mitigate the effects of urban heat, its overall environmental impact has yet to be assessed, particularly in terms of its carbon footprint.

Green roofs: another idea for making our buildings more sustainable
The 'La Tour des Cèdres' green roof initiative shows that it is possible to make buildings more sustainable right from the design stage. But we can also think about how to make existing buildings more environmentally friendly. One increasingly popular method is to green the roofs of buildings, including factories and structures in industrial areas.

Reduced energy costs
Green roofs offer significant savings in energy costs. In winter, they reduce heat loss by up to 30%, while in summer, the soil and plants absorb heat, reducing the need for air conditioning. A Canadian study found that green roofs could save 20% of energy in summer for the upper floors of buildings, which translates into a 6% reduction in energy consumption for a building of five storeys or more, and 10 to 12% for a two-storey building.

Extending the lifespan of buildings
Green roofs can also extend the lifespan of buildings by protecting roof membranes from climatic stresses such as wind, ultraviolet rays and temperature variations. This protection can double or even triple the roof's lifespan.

Ecological benefits
As well as saving energy, green roofs play a crucial role in retaining rainwater, absorbing up to 75% of precipitation. They also help to reduce urban heat islands, improve air quality by filtering polluting particles and storing carbon dioxide, and reduce outdoor noise levels.

Conclusion: towards greener construction
The green tower 'La tour des Cèdres' in Chavannes-près-Renens is an emblematic example of the innovations possible in sustainable construction. By considering solutions such as green roofs for existing and future buildings, companies can not only reduce their environmental impact but also improve their brand image, energy efficiency and the well-being of their employees. As the construction sector continues to look for ways to become greener, integrating vegetation into urban structures is proving to be a promising avenue.


Sources
rts.ch - Article
greenroofs.org - Article
livingroofs.org - Article
greenroofers.co.uk - Article
livingroofs.org - Article
treescience.com.au - Article

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