Green roofs consist of live vegetation established on top of buildings. It’s also known as a living roof, vegetated roof or eco-roof.
The plants and soil (or other material) sit on top of a synthetic waterproof membrane that protects the building from penetration of water, water vapour and roots.
How do green roofs work?
The plants and soil on a green roof capture and help filter rainwater when it rains. Rainfall that lands on a green roof eventually returns to the atmosphere through evaporation and through regular plant processes.
Green roof plants that are suitable follow this criteria:
- Drought-tolerant requiring little or no irrigation after plants have established.
- Self-sustaining without the need for fertilizers, pesticides or herbicides
- Able to withstand heat, cold and high winds
- Very low-maintenance
- Perennial or self-sowing
Green roofs offer a number of hydrologic, atmospheric, thermal and social benefits for the building, people and environment:
- Reduces the amount of stormwater runoff
- Improves the quality of water that returns to the storm system
- Reduces ambient air temperatures and increases humidity levels in the surrounding areas
- Improve air quality: Filters and binds dust particles and filters airborne toxins
- Increases energy efficiency (heating in the winter and cooling in the summer)
- Increases building roof membrane life by protecting the underlying components against ultraviolet and thermal degradation
- Increases aesthetic appeal and useable green space
- Increases property value
- Absorbs external noise pollution