Green roof with irrigation at Kaufland Moreni

3 min read

The extensive green roof we implemented with an irrigation system is a clear example that sometimes it is worth taking one step further, even in a moderate sub-Carpathian climate. In theory, sedum plants could have managed on their own, but we chose irrigation for energy efficiency reasons, not as a daily obligation.

Irrigation is especially helpful during long periods without rainfall, when vegetation enters a kind of forced dormancy and the roof layers would dry out due to the lack of evapotranspiration. With controlled water supply, plants retain their color better, establish more uniformly, and recover faster after episodes of thermal stress. In practice, the roof looks stable rather than “tired,” regardless of the season, and cools the building through evapotranspiration.

The evapotranspiration of 100 m³ of water over a few summer weeks on an extensive green roof provides active cooling far exceeding the cost of the water, and is dozens of times more efficient than the thousands of kW of electrical energy consumed by air-conditioning systems.

The system is discreet, integrated into the vegetation layer, and operates only when needed. It does not turn the roof into a high-maintenance garden, but instead provides long-term resilience. From our experience, this solution extends the lifespan of the green roof and preserves its natural appearance, without forced interventions or unnecessary resource consumption.