How many types of green roofs are there?

The NaturBuild project, co-funded by the Erasmus+ programme of the European Union, studied the different types of green roofs installed in Portugal, Greece, Spain and Italy. The types depend on the location and characteristics of the roof. 

The most common types of roofs   

• Intensive roofs are common in Portugal and allow the placement of perennials, herbaceous plants, shrubs and even trees, allowing for a great variety and imitating the natural soil. These can be placed at different heights and profiles, and require quite a lot of maintenance, including pruning, irrigation, etc.   
• Semi-intensive roofs are usually composed of herbaceous ground cover plants and shrubs. Their design can be varied, but is limited compared to intensive covers. Like the previous ones, they are also common in Portugal. 
• Extensive roofs aims to accelerate the natural colonization process, using native vegetation to establish a long-lasting population that functions autonomously and sustainably, i.e., beyond imitating the soil conditions of the plant, it requires little or no maintenance. This type of roofing is common in Italy and Spain.