How cultivate roofs with nature and energy

Twenty trainees met on Monday the 4th of May in the City Hall of Blois, then in the House of employment hall of Romorantin to learn BioSolaRoof construction. This training was proposed to builders and landscape professionals during four days. This course was the first one to be implemented in France.

Let’s grow on our roofs: biodiversity days

Sought in recent years to produce solar energy, green roofs are now being used to host biodiversity and produce wealth. The nature is back in the city bringing along the vegetal life and its fauna.

While solar power has been monopolizing roofs turning them into financial investments, a parallel movement has emerged aiming at protecting biodiversity and health.

They are ecologists, architects, gardeners, urban farmers or scientists, what brings them together? They are all passionate about plants. Their strength: being logic. Our cities no longer breathe, city dwellers need oxygen and nature functions must be restored before our cities become unfit for life.

BioSolarRoof: a new vision for green roofs

By simply combining plants and green technologies, the BioSolarRoof project resumes a set of current issues at the heart of our concerns: health, well-being, ecosystem balance, intelligent use of energy.

Transversally, we can say that its role is to promote an ecological approach that offers a rare compromise between supporters of Lowtech and Hightech.

In a nutshell the project aims at creating positive synergies between plants and energy production on rooftops.

Here, the advantages of combining green roofs and solar panels are recalled:

- The efficiency of the panels increases by 8 to 10% in summer - thermal improvement: reduction of heat in the summer, significant improvement of summer comfort - retention of rainwater and reducing the tax on storm water - Return of biodiversity and Ecological Balance

In France, despite some delays, green roofs are growing more and more. The thermal performance of a building with a green roof is now acknowledged and can even be calculated. And across the city, these are numerous and many of them include green roofs in their PLU (local urbanism planning) to make up for the lost green areas on the ground. Benefits of city plants are well established, we recognize all the services provided by urban biodiversity and its positive impact on reducing heat during peak of summers and enhancing air quality, human health, individual and collective well-being.

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In this context of development, the BioSolarRoof project has brought together two professions (gardening and production of energy), and promotes a return to the natural balance including the balance between the modern world, technology and return to a healthier life, closer to nature.

The plants chosen in this project are primarily local or wild species which, in a vision of sustainable development, contribute to the balanced development of local biodiversity. The roof is a living space for development of species which may be due to the choice of plants and development of space for a whole variety of invertebrate species and pollinators.

This new vision has a special place for gardeners who will be able to practice new plant solutions that meet both the needs of nature and the expectations of customers also. They can offer an esthetic, robust and low maintenance roofing. This is a new way that is developing and with it one can assume that the people interested in gardening will just have to find their way up to their rooftops.

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There are photovoltaic benefits also from the presence of plants to increase their efficiency by reducing heat. Their installation is carried out with new systems that pose no particular difficulty in operations. The substrate is added to entire weight. Servicing is required; plant on the outskirts of the panels must not grow too much. Therefore, the BioSolarRoof project provides a method of growing plants and introduction of the substrate.


The employment related considerations are not immune to the project which aims to provide training for working on the new roofs. The objective is to educate both the influencers and to train technicians for their installation.

The success of this project is primarily to respond to an issue that is a compromise between what is favourable to biodiversity and what is acceptable by the general public. But it is also a way to change the behaviour and views from the awareness of a difficult questionable principle, that what is good for nature, is good for mankind.