We are always excited about green roof projects because of their numerous benefits. Promoting and installing vast green roof systems citywide will benefit all urban residents with cleaner air, water, decreased noise pollution and improved health. With the current climate crisis in full swing, we believe that these systems should be installed wherever and whenever possible. If we can educate each other and our policy makers, we can change neighborhoods and eventually entire cities! With the proper structural soundness, any flat or moderately sloped roof can be transformed into a green oasis.
One of the biggest potential benefits in any city is the effect green rooftops could have on our storm water systems to prevent flooding. Green rooftops can retain 50 – 90 percent of a typical rain fall on the roof. Green roof plants and soils collect and retain storm water, processing, purifying and filtering water more slowly, lessening the burden on our storm water and sewer systems. Unfortunately the success of this strategy depends on an increased number of green roof systems. Without the help of policies to increase these projects, it will be hard to enforce citywide. Increasing permeable walkways or streets would also help alleviate flooding.
A green roof will provide an insulating buffer that can lower your heating and cooling bills. A green roof increases the thermal performance of your home or building’s energy efficiency, thereby, decreasing your dependence on heating and cooling systems. A standard bare roof membrane absorbs solar energy, increasing the temperature of the space below. The green roof plant and soil processes perform photosynthesis, evapotranspiration and evapotransmission, lowering the temperatures below the green roof, keeping your home cooler in summer months. Research also indicates that a green roof can be helpful in reducing heat loss through the roof of a building in winter, but the changing moisture content of a green roof system makes this a more difficult figure to estimate. Energy savings need to be calculated on a project to project basis.
Plants and trees on a large scale are also helpful in cooling our environment. Cities have higher average temperatures compared to outlying suburban or rural locations, a phenomenon called “Urban Heat Island Effect”. Structures and hard reflective surfaces like rooftops are responsible for absorbing solar radiation, pushing it back into our atmosphere, creating these higher temperatures. Greater numbers of gardens, trees and green rooftops in urban areas can convert this heat through evapotranspiration to purify the air, reduce smog and lower overall temperatures, decreasing our reliance on energy for cooling systems.
As cities grow, surrounding land is lost to development. Creating and maintaining new green spaces for people and creatures can be difficult. Rooftops are generally ugly, unused spaces that can be transformed into beautiful and functional green spaces. People are not the only ones who will benefit from a green roof. Habitats for our much needed beneficial insects, butterflies, and birds are hard to preserve where people are present. When designing a new green roof, determine which species your green space could target, so the best native plants, growing medium and resources can be selected for that species to thrive.
Who doesn’t love a summer day strolling in the park?! It’s been known for centuries that green spaces and access to the great outdoors can provide numerous health benefits. Gardening or simple access to natural spaces reduces stress, allowing people to participate in physical activities and cleaner air, away from the hustle and bustle. Office buildings and hospitals with green roof systems and recreational outdoor areas show increased productivity, less sick days in staff, faster recovery time and better overall health. If you live or work in a highrise, greenery on the rooftops below can be a welcome aesthetic improvement.