A green roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems.
Benefits of Green Roofs
- Storm-Water Retention
- Reduces Energy Consumption
- Reduces the Urban Heat Island Effect (Cooler City)
- Waterproofing Membrane Protection
- Improved Air Quality
- LEED and Green Globes (Certification)
- Sound Insulation
- Increased Property Value
Two Types of Green Roofs
- Intensive green roofs
- Are essentially elevated parks. They can sustain shrubs, trees, walkways and benches with their complex structural support, irrigation, drainage and root protection layers. The foot or more of growing medium needed for an intensive green roof creates a load of 80-150 pounds per square foot.
- Extensive green roofs
- Are relatively light at 15-50 pounds per square foot. They support hearty native ground cover that requires little maintenance. Extensive green roofs usually exist solely for their environmental benefits and don’t function as accessible rooftop gardens.