What is a vegetated or green roof? The straightforward answer would be it’s a roof with plants on it…but a vegetated roof (VR) is much more than that.
A green roof, also known as a rooftop garden or vegetative roof, is a roof of a building that is partially or completely covered with vegetation and growing media over a waterproofing membrane. Other vegetated roof components include a root barrier, drainage layer and filter fabric.
Beyond just the aesthetic appeal, VR systems benefit the building owner, community and architectural team by integrating sustainable design principles that can contribute to other eco-friendly goals and certifications.
While the plants reduce carbon dioxide and produce oxygen which are helpful for the environment, here are some additional advantages of vegetated roof systems:
- Extend the life expectancy of a roof
The vegetation on a VR system protects the roof surface from direct UV exposure, impact and other conditions that can weather a roof over time. With proper maintenance and upkeep, a green roof can extend a roof service life to up to 60 years. This protection therefore offers long-lasting economic benefits to the building owner. - Enhanced stormwater management
Green roofs reduce storm water runoff by absorbing rain that would otherwise flow to impervious surfaces like concrete that could cause flooding in urban areas. - Improve energy efficiency
Vegetation offers shade and cools the surface of the rooftop, mitigating the heat island effect, where the temperature in cities is higher than surrounding rural areas. According to the Environmental Protection Agency (EPA), "The surface temperature of green roofs can be 56°F lower than those of conventional roofs; and can reduce nearby air temperatures by up to 20°F." Roof vegetation also helps cool the interior building temperatures, resulting in greater energy efficiency and potential savings on heating and cooling costs. - Increase biodiversity
Adding a green roof can help preserve and protect any endangered native flora and fauna and provide otherwise unavailable habitats for urban wildlife, such as birds, bees and insects. - Improve air quality
As many green roof system components are made of recycled materials, they help divert many sources of plastic pollutants every year from entering landfills. A rooftop garden also allows for natural filtering of airborne pollutants, therefore creating cleaner, breathable air. - Beautify the built environment
Vegetated roofs add beautiful, usable space to an otherwise industrial and/or urban property. This direct exposure to nature can even improve occupant satisfaction and retention.
