Generally, extensive green roofs system has high potential to save energy during summer in Continental Mediterranean climate. Even though the experiments were done with 20% of total coverage plants, a good insulation effect was observed comparing to traditional constructive solutions (with insulation layer). These facts show the great influence of the substrate and drainage layer in the thermal behaviour of green roofs systems, and the great potential as insulation of these layers. In addition, the use of rubber crumbs as drainage layer material in extensive green roofs has a similar behaviour as volcanic gravel roof and it’s environmentally friendly.