What are Green Roofs?
A green roof is known as a “vegetated roof,” “living roof,” or “eco-roof.” It is an extension of an existing roof which involves a high quality waterproofing and root repellent system, a drainage system, filter cloth, a lightweight growing medium, and plants. Green roof implementation involves the creation of “contained” green space on top of a human-made structure. This green space could be below, at or above grade. But in all cases the plants are not planted in the “ground.” Green roofs can provide a wide range of public and private benefits.
Green roof systems may be modular, with drainage layers, filter cloth, growing media and plants already prepared in movable and often interlocking grids; or loose-laid/ built-up where each component of the system may be installed separately.
Many different green roof products on the market can be used to respond to specific design opportunities and constraints. While all green roof systems contain the same basic components, the products and installation methods used will vary to meet design requirements, project constraints, and benefit objectives, making each green roof unique.
– Green Roof Design and Installation: Resource Manual