Green roof using Sphagnum:
an ecological asset for sustainable constructions
Little known in France, the herbal coating combines all the advantages. Installed on the terraces or low-slope roofs, it is part of a sustainable development process providing natural insulation for buildings.
The principle of the green roof also called plant roof, vegetated roof or “eco-roof” is to cover with greenery a flat roof or low slope roof. This technique has been known for centuries in Scandinavia and among the Inuits, combining many advantages. Indeed, within an urban area, a vegetated roof can help to restore biodiversity. This solution also offers great opportunities for filtration and biological treatment of rainwater. It can also limit the massive inflows of rainwater into storm water drains. A green roof can absorb up annually to 50% of the water that falls on a roof, thereby reducing water treatment costs by 5 to 10%. The vegetation of urban roofs can also decrease the rate of CO2 in the air while capturing pollutions (airborne dust and pollen).
In addition, the technique allows the green roof to insulate the building naturally. The mixture of soil and plant roots on the roof makes it possible to make roofs airtight and watertight but also more resistant to wind and fire. In recent years using green roofs has become part of current practices in sustainable building, the architectural version of the philosophy of sustainable development. Indeed, the vegetated roof terraces help protect the waterproofing materials (insulating membrane) from UV radiation and solar heat. This natural protection increases durability of waterproofing membranes up to 30 to 50 years.
Another interesting point, a green roof greatly reduces the large temperature differences. This means that building materials are less exposed to the classic physical stresses due to expansion. Reducing variation in temperature by quasi 40% provides an obvious comfort to the occupants of the building covered. Moreover, you better control the temperature to limit energy consumption for air conditioning in summer and heating in winter.