What is a Green Roof?

Very simply put, a green roof is a living extension of an existing or newly constructed roof. It incorporates a water proofing membrane and root barrier, a green roof system, a drainage system, and lightweight growing medium and plants. Each green roof is unique, reflecting its owner’s needs, the particulars of the roof, and the geographic location of the building.

Advantages Over Conventional Roofs

A green roof partially or completely covers a roof, providing a multitude of advantages over conventional roofs. In addition to greatly improving the aesthetics of the immediate area and providing increased green space and biodiversity, green roofs can also reward a building owner with long term financial benefits. Based on Gallup polls and current real estate statistics, green roofs add proven value to your building. They can also reduce energy costs and extend the life of the roof by more than 50%.

Benefits to the Environment

Green roofs are amazing in their ability to clean and cool the air, keep storm water out of sewers and waterways, and they beautify your space and the community. Green roofs and living walls clean the air by consuming carbon dioxide and emitting oxygen. They reduce the volume of storm water runoff by absorbing and retaining water that would otherwise flood the storm sewer system resulting in sewage spills and overflows. The City of New York, through their PLANYC 2030 program, demonstrates that municipalities are catching on to the public benefits of green roofs in a big way. Accordingly, they proposed a significant incentive program, off-setting the installation cost of a green roof by 35%. Legislation was passed in June by the New York State Assembly, and signed into Law by Governor Patterson, providing $4.50 per square foot for the installation of green roofs in New York City.

Types of Green Roofs

There are three types of green roofs. Extensive, intensive and hybrid.

• Extensive: growing medium (soil)
  is less than 6 inches.
• Intensive: growing medium (soil)
  is greater than 6 inches.
• Hybrid: includes elements of both.

The choice between extensive or intensive depends on access, budget, maintenance, visibility, and load bearing capacity.