Green roofs are defined as vegetated roof covers where growing media and plants take the place of shingles, tiles, or other traditional roofing materials. All green roof construction includes waterproofing, drainage, growing media and plants.
The layers of a green roof
-6 inches or shallower.
-Usually designed with engineering and performance goals in mind.
-Extensive green roofs, though much lighter than intensive green roofs, can still weigh 15-50 pounds per square foot.
-Extensive green roofs are usually not designed for public access.
-Ideal plant types for extensive green roofs include those that are low to the ground, that will not be destroyed by nesting birds, that require less maintenance, and those that can tolerate a variety of weather conditions.
-Extensive green roof Benefits:
-Reduces storm water run-off
-Mitigates urban heat island
-Creates wildlife habitat
-Reduces energy costs and consumption
-Reduces noise levels
-Increases life expectancy of roof
-Improves aesthetic environment
Intensive green roofs
-Deeper, typically greater than a foot,
-May merge into on-structure plaza landscaping, such as lawns, large perennial
-Can hold plants, trees, and agriculture
-Require regular maintenance
-Roof must have strong structural support, or plant beds can be placed directly above walls or structural beams