What is a Green Roof?
Green roofs are a surefire way to make your building and community more sustainable. They have the potential to double or even triple the lifetime of your roof, reduce your energy bills, and can help prevent flooding. They can also beautify your home or office building, which has proven benefits on people’s sense of well-being. But what exactly is a green roof? How do these benefits work? And how hard is it to maintain?
What is a green roof?
Simply put, they are roofs that have a top layer of plants. There is no soil involved, instead a lightweight medium provides water and food for the plants. The substrate is underlaid with an impermeable barrier to waterproof and “plant proof” your roof.
How do they benefit the building?
Green roofs provide a protective layer against external pressures like the sun, wind, precipitation, and extremes in temperatures. Because of this, installing a green roof typically doubles or triples the roof’s lifespan. In fact, a green roof usually pays for itself after 8-21 years (2).
Having a green roof can also reduce the amount of energy needed to heat and cool your building. This is because the plants and their growth medium acts as a thermal mass, which helps regulate extremes in temperature and saves you money on your energy bills.
Because of their ability to extend the lifespan of your roof and save on energy bills, installing a green roof improves the building’s resale value. Plus, green roofs can provide up to 15 LEED credits to the building. Not convinced yet?
How do they benefit the community?
Green roofs absorb and filter rainwater. Their ability to absorb water helps regulate groundwater levels, which helps protect the surrounding area from sewage and septic flooding. Through filtering rainwater, they also reduce the effects of acid rain.
They do not only purify water, they also naturally purify air via conversion of CO2 and absorption of particulate matter. This effect is especially important in urban areas where CO2 emissions and air pollution can exceed the levels legally allowed by the United States Clean Air Act. Regular implementation of green roofs can provide cleaner air for the community.
And finally, green roofs can reduce a city or town’s Urban Heat Island effect. This Urban Heat Island effect refers to increased temperatures in urban settings due to human activity. It is largely affected by building materials: concrete, for example, absorbs a lot of energy from the sun and releases it as heat throughout the night. Because concrete rules over urban areas in the form of streets and large buildings, this heat release contributes to a significant increase in temperature. Green areas on the other hand absorb and mitigate heat rather than releasing it. Incorporating more green areas, for example green roofs, in urban settings has proven to reduce this Urban Heat Island effect.
How hard are they to maintain?
Maintenance is minimal but still an important consideration for prospective buyers. Maintaining a green roof is similar to maintaining a yard or garden. They require fertilization and de-weeding once or twice per year. And although green roofs are designed to require minimal to no water, it is recommended that an irrigation system is installed. This is usually only used during periods of drought or excessive heat. Otherwise, they are usually designed to avoid the need to water regularly.
Considering installing a green roof?
Didn’t consider installing a green roof pre-construction? No worries: It is possible to install a green roof post-construction. A professional inspection to check weight bearing ability is recommended. Reach out to one of the sources below for further information:
Andy Creath, Green Roofs of Colorado
Company/Organization: Green Roofs of Colorado
Phone Number: (303) 912-1941
Profile: Green Roofs of Colorado, LLC is a commercial and residential green roof and outdoor amenity space design, installation, maintenance, and consultation company founded in 2006. Premier installations include Denver Botanic Garden’s Mordecai Children’s Garden, Community College of Denver Confluence Center, Clyfford Still Museum, Mile High Stadium, and The University of Colorado’s Anschutz Health and Wellness Center
Donald Whiteley, ADA Compliance by Whiteley Consulting
Company/Organization: ADA Compliance by Whiteley Consulting
Email: lwhiteley@whiteleyllc.com
Phone Number: (303) 549-5010
Profile: Donald (Leo) Whiteley is president of ADA Compliance by Whiteley Consulting, a Structural Engineering firm undertaking the following 3 pillars of Professional Services: ADA Compliance, Historic Consulting, and Green Roof Consulting.
About the Author
Kiandra Kormos, Emerging Professional
Kiandra is a sophomore student at the University of Colorado Boulder studying Biochemistry and Atmospheric and Oceanic Sciences. A few years back, she began to incorporate sustainable practices into her daily life: she cut out red meats, sold her car, and limited single use plastics. She began to learn more about sustainable practices and found herself particularly intrigued by all the ways people have made their living spaces more environmentally friendly, including many that were incredibly simple. Her position with the Colorado Green Building Guild has allowed her to deepen her green home knowledge and she feels honored to be able to bridge this knowledge to her peers. She hopes that by sharing sustainable practices with her generation early on, they will have the know-how to build more sustainable communities in the future. When Kiandra is not at school you’ll likely find her in the mountains: she is a ski instructor at Eldora Ski Resort in winter months, and an avid hiker in the summer.
References
“Benefits and Advantages of Green Roofs for Building Owners.” Green Roof Technology, www.greenrooftechnology.com/advantages-of-green-roofs. Accessed 28 May 2020.
“Benefits of a Green Roof.” Sempergreen, www.sempergreen.com/en/solutions/green-roofs/green-roof-benefits. Accessed 28 May 2020.
“Green Roof Installation.” Green Roofs of Colorado, greenroofsco.com/green-roofs/installation/. Accessed 28 May 2020.