also: りょっかやね
noun
roof garden; green roof
A roof covered with vegetation, often for environmental or aesthetic purposes. The term is straightforward and commonly used in architectural and ecological contexts.
このビルには緑化屋根があって、夏でも涼しい。
This building has a green roof, so it stays cool even in summer.
緑化屋根は都市のヒートアイランド現象を和らげるのに役立つ。
Green roofs help mitigate the urban heat island effect.
屋上庭園 is a rooftop garden, often implying a recreational space, while 緑化屋根 emphasizes the ecological function of a vegetated roof.
Compound of 緑化 (greening) and 屋根 (roof). The reading りょっかやね is a contraction of りょくかやね, common in casual speech.