Capillary smart roofs are a unique type of extensive green roof equipped with an additional water retention and drainage system underneath the vegetation layer. During dry periods, the stored water is naturally (i.e. without energy input) returned via capillary fiber cylinders to the vegetation layer. Because 100% of the storm water can be reused for irrigation, smart roofs represent cyclic water management. They additionally provide benefits similar to extensive green roofs including basic habitat provision, reduction of localized air temperature and storm water management.