Advantages and Disadvantages of Green Roofing

Green roofing is made up of a vegetation layer that is planted on top of a waterproof system installed on a slightly-sloped or flat roof. Green roofs also are called eco-roofs or vegetative roofs.

A green roofing system is an extension of an existing roof. At a minimum, it involves plants, a lightweight growing medium, filter cloth, drainage system, root repellent system, and high-quality waterproofing. A modular green roof consists of portable small planting beds that are placed together to make a more prominent green roof, while other green roofs are one large installed integrated section. 

A green roof system can be modular, with plants, growing media, filter cloth, and drainage layers already prepared in movable and frequently interlocking grids. Or they can be built-up or loose-laid where each of the system's components is installed separately. Developing a green roof involves creating a "contained" green are on top of a human-made structure. The green space can be above, at, or below grade. However, in all instances, it does not reach to the ground. A green roof can offer a broad range of various private and public benefits, and they have been installed successfully in countries all over the world. Many roofing contractors have already adopted this new technology.

Not only do green roof technologies provide building owners with a proven and reliable return on investment, but they also offer opportunities for significant environmental, economic, and social benefits, especially in urban areas. 

Urban greening has been promoted for quite some time as an effective and secure strategy to increase investment opportunities and beautify the environment.

With a green roof, the substrate stores water, and it is then used by the plants and sent into the atmosphere via evaporation and transpiration.  

During the summer, a green roof can retain 70% to 90% of the rain falling on it. In the winter, a green roof can maintain 25% to 40% of the precipitation that falls on it. 

Not only does a green roof retain rainwater, but it also moderates the water's temperature and acts as a natural filter for water runoff. 

A green roof reduces stormwater runoff and delays the time that the drainage takes place, which results in less stress being placed on the sewer system during peak flow times. 

Plants on a green roof can filter harmful gases and capture atmospheric deposition and airborne pollutants. The temperature moderating effects that a green roof has will help to reduce the demand on power, and potentially reduce CO2 as well as other polluting by-products that are dispersed into the air. 

The increased water quality and reduced pollution provided by green roofs can reduce healthcare demands as well. Green roofs can increase public safety, the feeling of community and social cohesion, and also serve as community centres. When a green roof is used as an urban agricultural project is can help to reduce the footprint of the community by creating a local food system. Those projects can improve nutrition levels, increase feelings of self-reliance, and help to empower the community. 

A green roof can increase the marketability of a building. They symbolize the green building movement and may serve as an incentive for people interested in the numerous benefits provided by a green roof. Vegetative roofing is a very viable alternative for future construction, due to it's environmental advantages. It will be amazing to watch it's progression in the next few years.