Major cities around the world and the politicians that govern them are starting to take environmentalism very seriously. The effects of climate change are already visible and efforts to combat the negative impact humans have on our environment are growing. Green roofs are just one example of environmentalism in action in urban centres around the world. Also known as a living roof, Wikipedia defines it as “a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane” which “may also include additional layers such as a root barrier and drainage and irrigation systems.”

While this definition seems comprehensive, there are actually many kinds of solutions including intensive, extensive, new, retrofit, modular systems, complete systems, and pre-cultivated vegetation blankets. Depending on the city in which you live, there are likely different guidelines with respect to what is required of a green solution. In the city of Toronto, for example, a green roof assembly must include a root repellant system, drainage, a filtering layer, a growing medium, plants or vegetation, and a waterproof membrane.

Three Main Types

In general, there are three main types of roof systems: complete, modular, and pre-cultivated. Complete roof systems contain many components, including a roof membrane, which are all integral parts of the system. Modular roof systems are placed above existing roof systems. Finally, pre-cultivated roof systems include vegetation blankets that are made up of a growing medium and plants that are rolled out over an existing roofing system and use drainage mats and root barriers.

Intensive Versus Extensive Roof Systems

Intensive green roof systems are also known as active green roofs and they feature an elaborate growing medium that can support a wide variety of landscaping designs and plant growth. In many cases, intensive roof systems are accessible to the public and make for excellent recreational spaces. Alternatively, extensive green roofs feature a much less extensive growing medium and as such landscaping requires less maintenance but is also designed to be self-sustaining rather than a recreational space. These green roofs are less expensive, lighter, require less support, and need less maintenance than active green roofs.

New Versus Retrofit

Green roofs are increasingly common designs for new buildings that are built to be environmentally responsible. Buildings designed with a this so;ution bring many benefits; for example, new buildings are designed to support the landscaping and will not require reinforcement later. More importantly, the building is usually designed with the aesthetic appeal of this types of roofs in mind. However, retrofit roofs are also increasingly popular. A retrofit simply means that the roof was added to the building much later. Unfortunately, because roofs require much more structural support than traditional, a retrofit can be quite costly. Nevertheless, the environmental benefits of roofs make retrofit a popular choice for building owners especially when you consider the environmental benefits.

Indeed, green roofs are known to reduce heating and cooling costs as they provide enhanced insulation. In addition, this kind of roofs provide natural habitats for urban wildlife while they also filter pollutants and carbon dioxide from the air. Increased agricultural space, reductions in energy usage, and even federal and local tax incentives are all benefits of green roofs.