Madeline Iffert
Dr. Freymiller
RCL 14
Green Roofs:
Offering the Trifecta of Sustainability
Audience: This essay is aimed toward business owners or school officials who are
looking to construct a new building or renovate an old one. It is important for them to
hear this message because it will open up opportunities for them to save money and
increase the value of their property.
“The Earth is not a gift from our parents; it is a loan from our children.” This
insightful Kenyan Proverb shares wisdom about how we as humans should treat the earth.
It directly relates to the idea of sustainability: using resources now in an efficient manner
so as not to compromise the future for our children. Green roofs are the way of the future
in turning our loud, polluted world into one that is more sustainable, healthy, and
beautiful. The term green roof has a dual meaning: it is a roof that is much greener, as in
more environmentally friendly, than a standard roof, but it is also the term for a specific
technology. Basically, a green roof is a garden of lush vegetation on top of a roof—think
Hanging Gardens of Babylon. The roof can be installed relatively easily on a preexisting
roof or can be built into the design plans of a new building. This enables green roofs to be
very accessible. Each roof is unique because it is designed for the climate and geographic
area the building is located in. Although they are just starting to get press now, green
roofs have been around for centuries, proving that this is a tried and true method of
building roofs. By implementing these roofs into our cities and neighborhoods, we could
make the community cleaner and more beautiful. Businesses, schools, and homeowners
alike should seriously consider implementing green roofs into future or preexisting
buildings because they offer numerous public and private benefits in the economic,
environmental, and social realm; green roofs increase energy efficiency, help with rain
and weather control, and enhance the beauty and biodiversity of the community.
Iffert 2
There are so many benefits for the private owner that implements a green roof in
their building construction. Energy efficiency is one of the top reasons a company or
property owner should consider a green roof. The green roof technology acts as natural
insulation, helping to keep the building cooler in the summer and warmer in the winter.
According to a chart in The Green Roof Manual, a study conducted during June showed
that green roofs greatly reduce the temperature of the roof. A standard black roof had an
initial temperature of 60 degrees Fahrenheit and by the peak heat of the day reached
about 110 degrees Fahrenheit. By the end of the week, the roof temperature was over an
astounding 160 degrees. The green roof on the other hand remained steadier in the
temperature throughout the week. The initial temperature of the green roof was about 70
degrees Fahrenheit and barely fluctuated each day. The temperature changed only about
10 degrees on the green roof compared to standard roof temperatures which fluctuated up
to 100 degrees on some days. By the end of the week the green roof was at 100 degrees
Fahrenheit—a whole 60 degrees less than the black roof (Snodgrass 31). The stability of
the temperature allows for the heating and cooling equipment in the building to run less,
wasting less electricity and therefore becoming more energy efficient. In Toronto,
Environment Canada found that a building with a 4 inch green roof of substrate showed a
decrease in summer air conditioning by 25% (Dunnett 73). Twenty five percent reduction
of cooling costs is saving big money! That is a strong incentive for constructing green
roofs; businesses will have more profit, schools can redirect money in the budget, and
families can save this money for more exciting things than energy. In addition, if the
unfortunate event occurs where the air conditioning is broken in the summer, the building
will remain much cooler and allow for a more comfortable room for the inhabitants. Less
Iffert 3
running time allows for longer life of the heating and cooling appliances since they are
subjected to less deterioration. The extreme fluctuation of heat on standard roofs each day
causes stretching and compressing of the roof which leads to damage and the need for
repairs. With a green roof, the change in temperature each day is greatly reduced,
allowing for a more temperate building and reducing costs needed to repair wear and tear
on the appliances. Because of the increased energy efficiency, green roofs are great
money savers for the owners.
The green roof investors are not the only ones profiting from installing the
technology. In the public sector, green roofs are beneficial, especially when it comes to
weather. Although the debate about global warming continues, it is clear that
temperatures are on the rise as well as extreme weather. In the construction of a green
roof, drainage layers and thermal insulation are installed onto the roof. The growing
medium such as substrate is added on top and then vegetation is planted. Green roofs are
able to reduce the intense effects of different weather by making them more moderate for
the people living in the area. For example, during strong rainstorms, green roofs can help
with storm water management. The lush surface of the roof is able to absorb more water
than a traditional roof. The substrate of a green roof can retain up to 70-90% of
precipitation in the summer and about 25-40% in the winter (“Green Roof Benefits”).
This is extremely valuable because less water runs off onto the ground where flooding
may occur. One study showed that after the same amount of rainfall, a building with a
standard roof gave off 26 inches of runoff compared to the green roof with a depth of just
2 inches of substrate that only gave off 16 inches of runoff (Dunnett 59). That is a
significant difference and would definitely impact the amount of flooding that would
Iffert 4
occur. Runoff is very problematic not only because it can cause flooding, but also
because it can overflow into sewage and wastewater disposal systems which can then
lead to contamination of drinking water and waterways. No one wants to deal with major
flooding or have drinking water or rivers polluted. Other studies have shown that green
roof runoff is less polluting and has a higher pH (meaning slightly more basic) than
runoff from a standard roof. This higher pH is a good thing because it helps reduce the
effects of acid rain (Dunnett 61). Green roofs can greatly lower these harmful effects.
Communities want safe and healthy neighborhoods and cities for their children, and
green roofs are great ways to help reduce harmful risks.
Another important weather related advantage that green roofs offer is that they
greatly help to reduce the Urban Heat Island Effect (UHI). This is the phenomenon in
which cities are significantly warmer than their surrounding areas due to human
activities. Because cities are so vastly populated with people, buildings, and vehicles, the
city tends to heat up more than suburban or rural areas (“Heat Island Effect”). UHI leads
to many problems such as increased heat, smog, and pollution—three undesired effects of
city life. Installing green roofs on buildings in the city, especially on a large scale, can
reduce the effect of UHI. The plants and vegetation absorb energy from the sun and
convert it into food and energy for themselves. This diverts some of the sunlight that
would have been converted into heat. Therefore, the city will trap less heat, which will
alleviate some of the harmful effects of smog and pollution. The plants also consume
carbon dioxide produced from the building and surrounding areas. This too helps to
reduce pollution and the amount of greenhouse gases present in the area. As previously
expressed, the vegetative green roofs keep the buildings cooler in the summer which
Iffert 5
helps with fog and smog reduction. Implementing green roofs on a large scale in a city
can greatly reduce these harmful affects. It will lead to healthier and more comfortable
cities. This is especially important for businesses to take into consideration when
designing or renovating their company buildings in the city.
Another public advantage is positively enhancing the environment. Landfills are
filling up quickly and running out of space. As mentioned before, green roofs help to
prolong the life of the roof on the building because of less wear and tear from weather.
Not only does it decrease costs, but it also diverts waste from the landfills that would be
created if the roof continued to need repairs or replacement. Besides environmental
benefits of reducing smog and pollution, green roofs offer opportunities to increase the
biodiversity of the area. By offering more living space for creatures, the biodiversity will
increase and allow for native plant species to remain in the area. Birds will also have
more opportunities to find a home (“Green Roof Benefits”). It is important to keep waste
from landfills so communities can keep their distance from them. It is also vital to keep
native species alive and well in their environment.
Besides enhancing the environment, green roofs also enhance community life.
Green roofs abound in benefits that double for the property owner and the public as well.
Intensive green roofs use deeper soil and have a slightly more complex watering system.
This type of roof is designed for access so people can walk around and enjoy the green
roof. A green rooftop can offer a place for employees to take a break and stretch, to
rejuvenate after a tedious day in the office. They can unwind by taking in nature and
listening to the sounds of the breeze rustling leaves, despite possibly being in the heart of
a bustling city. Not only that, green roofs make the building look much more appealing.
Iffert 6
Seeing lush gardens, trees, and flowers on top of buildings will enhance the beauty of the
area. Installing a green roof has other benefits for the private owner as well. One is that it
increases the marketability of the property. The green roof shows that the building is part
of the green movement, which is currently very popular, so it would have a broader
market for selling. The aesthetic appeal of flora and fauna would entice potential buyers.
The beauty of a soft natural landscape on top of an edifice is a refreshing view. It can be a
place of biodiversity and learning, having educational programs for employees and their
children. Especially in cities, increasing the amount of green space is wonderful since
most of the city is comprised of streets, sidewalks, and buildings. Having an accessible
green roof would allow people to enjoy the experience of a park and have a location to do
recreational activities. This is great for the health and wellbeing of the individuals who
take advantage of it. Even if the property owner does not want to allow access to the top
of their building, an extensive green roof is a great option. This type of green roof is not
meant for public access. It needs minimal maintenance of weeding only about twice a
year and uses a simple irrigation system (“Green Roof Types”). This roof would still
enhance the beauty of the area and yield all the benefits, just minus a place for people to
enjoy.
In regard to economic, environmental, and social sustainability, green roofs
should be used in more communities. They increase energy efficiency, reduce intense
weather effects, and add beauty and more space to the buildings and surrounding areas.
Because of their versatile nature, green roofs can be constructed for anyone; they are
perfect for office buildings, schools, or even on family homes. By increasing energy
efficiency, they allow the property owners to keep spend less money on energy so they
Iffert 7
can have more to spend where they choose. Overall, the environment will be more
temperate and less dangerous during strong rainstorms. Green roof technology helps the
community by offering more green space as a place for relaxation, education, and
biodiversity. Green roofs are an extreme benefit to society and should be implemented
more often. The economic, environmental, and social affects are all intertwined and can
benefit individuals and the community as a whole. Green roofs are a fantastic way to start
doing your part to live sustainable lives so that your children and their children are able to
enjoy the earth. What if you could help make the world a cleaner, more efficient, and
more beautiful place? Would you take on the challenge?
Works Cited
Dunnett, Nigel and Noël Kingsbury. Planting Green Roofs and Living Walls. Portland:
Timber Press, 2008. Print.
“Green Roof Benefits.” Green Roofs For Healthy Cities. Web. 5 April 2013.
“Green Roof Types.” Green Roof Technology. Web. 5 April 2013.
“Heat Island Effect.” EPA. United States Environmental Protection Agency. Web. 5
April 2013.
Snodgrass, Edmund C. and Linda McIntyre. The Green Roof Manual: A Professional
Guide to Design, Installation, and Maintenance. Portland: Timber Press, 2010.
Print.