Rooftop Gardens (Green Roof)

Benefits of a Green Roof:

1. Reduce heating by adding mass and thermal resistance value and cooling through evaporation loads on a building- especially if it is glassed in so as to act as a terrarium and passive solar heat reservoir.
2. Increase roof life span.
3. Reduce stormwater run-off.
4. Filter pollutants and carbon dioxide out of the air.
5. Help to insullate a building for sound.
6. Filter pollutants out of rainwater.
7. Increase wildlife habitat.
8. Create a vegetable garden, water garden or perennial garden.

Green Roof Materials and Components:

1. Waterproofing Membrane: After the PVC membrane is installed, it is tested for leaks with a flood test.
2. Waterproofing Membrane: The top layer of the modified bitumen membrane is heat welded to the roof. A root barrier will later be applied to prevent penetration of the membrane.
3. Insulation: Extruded polystyrene is installed over the waterproofing membrane as an insulating layer, reducing energy costs for the building.
4. Drainage Layer: Good drainage is essential for a successful green roof. A lightweight synthetic drainage board ensures well-drained soil and proper aeration of the roots.
5. Substrate: Green roof growing medium - known as substrate - is typically a mix of lightweight mineral aggregate and organic matter.
6. Vegetation: Pre-grown sedum mats provide instant vegetation coverage. Other planting methods for extensive green roof include plugs, cuttings, and seeds, which take one to three years to become fully established.