Green roofs - Compositions and professional rules

Roof greening, particularly in urban environments, offers a number of complementary advantages. Green roofs provide enhanced thermal and acoustic insulation, thermal inertia for summer comfort, rainwater retention capacity, counterbalance the sealing of urban areas, improve air quality and maintain biodiversity in the city... They are also aesthetically pleasing and a source of heritage enhancement. Three types of vegetated roof can be envisaged, depending on the desired objective, the strength of the supporting structure and the budget available: a garden roof or intensive vegetation allowing traditional planting, a simple layer of vegetation or extensive vegetation of low thickness and requiring no maintenance, an intermediate system or semi-intensive vegetation offering greater ornamental diversity than the green carpet. In all cases, the roof waterproofing must be able to resist root penetration.