A roofing revolution: refocusing on rooftops can reduce energy usage, clean our cities and create a more sustainable future

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Content A ROOFING REVOLUTION:
REFOCUSING ON ROOFTOPS CAN REDUCE ENERGY USAGE, CLEAN OUR
CITIES AND CREATE A MORE SUSTAINBLE FUTURE
by
Katelyn Mary Petroka
A Professional Project Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF ARTS
(JOURNALISM)
May 2009
Copyright 2009 Katelyn Mary Petroka
Table of Contents
Abstract iii
A Roofing Revolution 1
ii
Abstract
The energy crisis, global warming and the rising temperatures in cities: these are
problems that are becoming more salient in the United States. And now with a new
energy-conscious president, the idea of a fresh start finally seems plausible. Most of the
solutions are not new: cut down on carbon dioxide emissions by driving less, use public
transportation and find alternatives to oil. However, it is somewhat rare to hear about
other innovative and sustainable practices that cut down on CO
2
emissions.
Though green roofs have an obvious aesthetic function, the connection between
installing vegetation on roofs and CO
2
reductions is not as widely understood. Green
roofs help reduce CO
2
emissions because vegetation, as opposed to hard concrete,
absorbs relatively less sunlight, which reduces internal temperature of the building and
the surrounding air. By reducing the building’s temperature and mitigating the “urban
heat island” effect, less energy is required to cool the building.
While green roofs provide many needed benefits, cool roofs have also shown to
decrease building energy consumption. Cool roofs, or roofs painted white have been a
popular cooling technology since the Ancient Greeks used them to keep their homes cool,
but more recently roofs have fallen out of the energy debate.
The current popular way to decrease energy usage is primarily centered on
changes inside the home-- installing LED light bulbs, more efficient appliances and
cooling systems. But there is an easier and cheaper way to cut back on energy costs: just
look up to the roof.
iii
We are at 2,000 feet, a few minutes from landing at LAX. A glance out the
window reveals a sprawling, contrived concrete-asphalt topography, dotted by blue
swimming pools and the occasional light-colored roof over a warehouse or factory.
Los Angeles, from this top-down perspective, may look quite different in the near
future. And experts on climate change and sustainable cities say the color scheme will
have to change. Or else…
The alternative vision, already being implemented in key parts of Southern
California, including downtowns throughout the region, will show up mainly as green.
Speckled throughout the greenery will be splashes, even expanses, of white and cream
squares, the roofs and parking lots will be covered by reflective coatings. It will be a
green-and-white checkerboard of colossal – and possibly life-saving – proportions.
Architects, designers, engineers and scientists all urge that we raise our eyes to
the rooftops. Building covers should either be painted with a light-reflecting white
coating or, if flat, either painted white or turned into a garden. That’s right, a permanent
place where sedums, flowers, shrubs and grasses are planted into soil.
Although the green and white rooftop vision is not explicitly spelled out in
President Obama’s green initiative, his plan to devote $60 billion to green technologies,
jobs and research is indicative that the United States is on its way to a more sustainable
movement spanning from New York City to Los Angeles.
As an environmentally-friendly state with some of the most progressive cities in
the country, many people believe California should, and can, lead the way in efficient
design by making simple adjustments to rooftops.
1
First, a few basics about green roofs. They come in two varieties, extensive and
intensive.
Intensive green roofs are meant to be accessible to the building dwellers and
resemble roof-top gardens, perhaps even with small trees and shaded benches. Both the
builder and architect need to keep weight in mind during the design phase, either for a
retrofit green roof or for the top of a building that is being planned from scratch.
Extensive roofs hold industrial-strength vegetation. Purposeful and functional,
they are not meant to be enjoyed, but rather cool whatever lies inside the building. In this
version, small plants are bedded in a few inches of light-weight soil, usually a mix of
minerals and organic materials like sand and peat.
Both roof types require more than just soil and plants, however. Because the
materials are on a roof instead of the ground, precautions must be taken to make sure the
plant roots don’t grow into the roof and seek nourishment below, which could lead to a
cracked, or worse, a caved-in roof.
So…green roofs must be built in layers, a bit like making a pizza.
First you need the dough. On a green roof, the dough is a specially designed
water-proof membrane that is placed on top of the conventional roof. Sometimes the
“root barrier” layer is needed, depending on the roof’s age and composition.
The second layer on a pizza is normally the sauce, in this case a drainage system
that removes excess water not absorbed in the soil. In some cases, this drainage system
can actually be linked to a cistern, which stores both irrigation runoff as well as rainwater
for a time when rain is scarce. This is likely a necessary component for a green roof in
2
Southern California due to the region’s semi-arid climate and the dry summer and fall
months.
Next comes arguably one of the most important parts of the pizza. The soil on a
green roof is the cheese layer. The soil depth and components depends on the type of
green roof and the plants. An intensive roof will normally have deeper soil, while an
extensive one will require a thinner layer.
Finally we get to add the toppings. And as there are all varieties of pizzas, so
there are different types of plants. It all depends on the budget and the climate.
“Native plants are an obvious choice because they are already adapted to the
climate and rainfall levels in an area,” Pablo La Roche, associate professor at Cal Poly
Pomona, says. Drought resistant plants do not require much maintenance and watering.
Native grasses, wildflowers, and sedums also provide a habitat for native
birds and insects. Sedums, or succulents, have been called “the easiest plants to grow”
because they require little water and are low-maintenance.
Plants must also be wind tolerant, provide good ground coverage, have shallow
root structures and withstand extreme temperatures. “Plants can’t require too much
maintenance because that means more money,” says Lynne Tjomsland, grounds and
gardens manager of the J. Paul Getty Museum in Los Angeles, which has several green
roof installations.
While installing a green roof is a fairly simple process, the benefits must be fully
explored to gain a complete picture of a green roof’s purpose.
Most of the research on green roofs has been done on the ecological benefits and
energy-reducing capabilities of extensive roofs. With the recent economic meltdown,
3
many people are looking for ways to save money. So how does a rooftop garden end up
saving a pretty penny on an air conditioning bill? The answer is two-fold.
During hot weather, green roofs are cooler than conventional roofs because plants
are masters at transpiration, which has a cooling effect. When liquid water is turned into
water vapor it consumes energy and becomes cooler. You can think of plants as miniature
air-conditioners because the air temperature around them is normally 10 degrees cooler
than the ambient air temperature. By cooling the outside air, the building’s internal
temperature is also reduced, requiring less air conditioning.
Another way green roofs help lower the monthly utility bill is through their ability
to mitigate what’s called the “Urban Heat Island Effect,” which has become a major
concern of scientists, policy makers and developers.
On balmy summer days, the air in urban areas can be 6 to 8°F hotter than the
surrounding suburban or rural areas. The increase in temperature is mainly caused by
buildings’ dark surfaces and little reflectivity. These dark surfaces absorb relatively more
heat from the sun, which warms the buildings and the air around them, increasing air
conditioning costs and pollution levels, especially in the summer.
The urban heat island phenomenon has become the focus of the Department of
Energy's Lawrence Berkeley National Laboratory, which formed the “Heat Island
Group”. Through extensive research the group has determined that, in the City of Los
Angeles alone, increased summertime temperatures from the heat island effect can
amount to an extra $100,000 per hour in energy costs, and about $100 million per year.
4
Clearly, the urban heat island effect is expensive, but it’s also compounding the
problem of carbon dioxide emissions, a greenhouse gas--most scientists agree-- is a major
cause of global climate change.
The connection is fairly simple. When less energy is needed to cool the building,
power plants don’t need to generate as much power, which cuts down the plants’ CO2
emissions. Adding a green or cool roof, which cuts down on air conditioning costs and
helps mitigate the urban heat island effect, is a viable solution to this problem.
But let’s forget energy reduction for a minute. Green roofs can provide other
natural services most urban areas are lacking.
The vegetation on green roofs helps prevent stormwater runoff which, in a city
such as Los Angeles, can quickly become a pollution problem especially in the rainy
months between November and March. Motor oil, paints, dirt and other pollutants are
washed away into storm drains which eventually flow into the ocean.
On a rainy day, up to 10 billion gallons of water flows off the rooftops and streets
of Los Angeles and into the storm drain system, according to a report by the
Environmental Affairs Department of the City of Los Angeles. When that water reaches
the ocean, it can seriously affect the heath of marine life.
Green roofs can also help bring bio-diversity back to cities as they serve as natural
habitats for birds and insects. While nature is reintroduced to the urban fabric, plants on
a green roof also help oxygenate the environment. Through photosynthesis, plants
convert CO2 gas back into breathable, life-sustaining oxygen.
The water-proof membrane, soil and plants all create a protective barrier that shields
the building’s actual roof from the elements. Presto: the roof lasts much longer. Studies
5
by the Environmental Affairs Department indicate that green roofs can nearly double a
conventional roof’s life from an average of 15 to 20 years to about 40 years.
“Of course there are many benefits to installing green roofs, like preventing storm
water runoff and oxygenating the environment, but the cooling effect is perhaps the
greatest benefit,” La Roche says.
Over the past five years, La Roche has studied the cooling effects of green roofs
by experimenting with square-meter plots on rooftops at the Cal Poly Pomona campus.
“Los Angeles has a perfect climate for getting good results from green roofs,” La
Roche says. The “perfect climate” he refers to is one in which the day time is relatively
warm while the temperature normally falls in the evening. “The reason green roofs work
so well is thermal insulation,” La Roche says.
That insulation can come from what’s called thermal mass: things like mud, stone
or water. Soil collects water that serves as insulation, keeping the building cooler than it
would be without the soil on the roof. La Roche believes a green roof should be
complemented with night ventilation, which essentially means opening windows to allow
for greater air flow.
“It doesn’t take any energy to just open the windows and air the place out,” La
Roche says. The idea is simple: thermal mass on top of the building stays cool
throughout the day even when the temperature rises again. “That swing in temperature
between cold and hot makes it the best climate for green roofs to work,” La Roche says
of Southern California’s weather.
Like most researchers, La Roche is itching to perform the green roof experiment
on a larger scale, on the tops of real buildings rather than on square meter cells. But
6
even without a super-sized experiment, La Roche is sold on the positive cooling results
from green roofs. “We have to do this, it’s unethical not to do it,” La Roche says
passionately.
So going green could be the right fit for some roofs, but what about retro-fitting
with white? White roofs have one vital attribute: a high albedo.
Albedo, which comes from the word “albino” meaning white, is a measure of how
reflective something is. White surfaces tend to have high albedo and reflect more sun
than black surfaces.
(Think about this: on a hot summer day would you rather stand barefoot on a
black asphalt road, or on a lighter-colored cement sidewalk? You made the decision not
to scorch your feet because of the albedo differences.)
The albedo effect tends to be the selling point for people contemplating a roofing
change, causing them to pick white or cool over green.
Cool roofs are painted with light- colored or reflective material. The idea isn’t
new, in fact, it’s ancient.
More than 2,000 years ago, Grecians kept their homes cool with light-colored
roofs even during the sweltering summer months. For decades, Bermudians have
understood that crushed limestone reflects the sun’s light, keeping the inside temperature
of their homes cooler than conventional dark roofs.
But in the 1970s, cool roofs got bit of a bad reputation in the U.S. because people
would just slather on a coating of regular white paint. After baking in the sun, the paint
would normally crack and peel off. A white-painted roof became a frustration rather than
an energy-saver.
7
Recently, they’ve re-gained popularity as a way to reduce energy consumption in
buildings because they reflect high amounts of sunlight. Cool roofs just need to be
designed correctly as well as durably.
According to the California Energy Commission, cool roofs can be 50 to 60
degrees F cooler than a normal roof. This can make a considerable difference on a hot
summer day. Because they are effective, in 2005 cool roofs were added to the
prescriptive requirements of California’s Building Energy Efficiency Standards.
This doesn’t mean that all buildings are required to add a cool roof. Rather, all
newly installed non-residential roofs must be able to reflect a large portion of the sun’s
energy.
“A cool roof is likely the most efficient way to meet this requirement,” Ronnen
Levinson of the Lawrence Berkeley Heat Island Group says. The Lawrence Berkeley
National Laboratory was the force behind the addition of the state’s cool roof
requirements.
Levinson is the “materials” man at the laboratory. His research focuses on how to
cool buildings and homes by simply adjusting the materials on the roof.
“A vegetative roof is in my opinion a very good technology, if you’re willing to
pay for it, but it’s not going to be cost effective,” he says. “There’s just too much money
needed for installation and maintenance for it to ever repay itself.”
But Levinson isn’t anti-green roof. “There are other benefits green roofs provide
and there is a need for them in Los Angeles,” he says. “But if we’re looking for a
technology that is the most cost-effective, as well as efficient, cool roofs are it.”
8
On average, a cool roof costs about $1.50 per square foot to install. Different
types of cool roofs vary in prices from 75 cents for a low-end coating, to about $3 per
square foot for reflective clay or concrete tiles.
Retrofitting a home or building with a green roof, on the other hand, can cost
about $15-$25 per square foot. However, if a green roof is installed during the
construction it generally costs about $10 to $15 per square foot.
The numbers can be deceiving when the increased roof life is not taken into
account. “A green roof can double the roof’s life and people tend to forget this when
looking at the upfront cost,” La Roche says.
The city’s Environmental Affairs Department found that when taking the
increased roof life into account, a retrofitted green roof only costs about $1.03 per square
foot. Installing a green roof is even cheaper when it’s added in the new construction of a
building: just 69 cents per square foot.
A conventional roof can cost from between $1.55 and $4.60 per square foot,
according to the General Services Division for the City of Los Angeles. It’s clear that by
comparing conventional, cool and green roofs, all are in similar price ranges, but a green
roof just takes more time to reach a pay-off point.
Bottom line: a green roof is worth the money over a long period of time. A cool
roof is worth the investment almost immediately because it’s cheaper to install and
provides nearly instantaneous energy savings.
“A cool roof can be installed pretty easily and economically,” Levinson believes.
“But people need to know their options.” After studying the solar reflectance of
9
different materials and their net energy savings, Levinson has narrowed down the best
types of roofing materials for residential homes.
“Clay and concrete tiles work well on a residential home, but they need to be
sprayed with a cool coating,” he says. Many of the coatings are made out of a plastic-like
substance called polymer. Metal is an excellent sunlight reflector as well, but its high
conductivity allows it to heat easily, so it also needs to a reflective coating.
On a flat-roofed non-residential building, Levinson believes applying a white
coating is the best option. “You don’t have to worry about a flat surface causing a glare
which can be distracting to neighbors or drivers,” he says.
Although cool and white roofs are not expressly required today, this will likely
change. Beginning in the summer of 2009, the California Energy Commission plans to
make highly reflective roofs required on new commercial buildings. Though the details
are not completely ironed out, white roofs will be mandated on new buildings with flat
roofs. Sloped roofs, including residences, will be required to have highly reflective
colors.
So where do green roofs match up with white ones? The question continues to
stir controversy within the building community in Southern California. Obviously, there
is disagreement over how to best reduce home and building energy usage.
Even though the California Energy Commission is backing up “cool,” La Roche
isn’t sold on the idea. “The green roof still worked better to cool the interior of the
building than a cool roof,” La Roche says of his research in Los Angeles.
Larry Kalkstein, director of the Synoptic Climatology Lab at the University of
Miami, disagrees with LaRoche: “Our research shows that adding more reflective
10
materials in Los Angeles would have a greater impact on reducing the urban heat island
effect”
Kalkstein and his team of researchers from around the United States have been
studying urban heat island reduction strategies for more than 15 years. The EPA uses
their research to understand the impacts of high temperatures in cities on health.
A 2003 study in Los Angeles compared cool roofs with increased vegetation on
both the ground and on rooftops. Kalkstein and other researchers found that during humid
heat waves the reflective surface, or cool roof, had a more significant mitigating effect
than increased vegetation.
“In Southern California the best strategy I’ve found is increasing urban solar
reflectance, or albedo, followed by increasing urban vegetation specifically on the ground
level,” says Haider Taha, a former staff scientist at the Lawrence Berkeley Laboratory
Heat Island Group where he examined different urban heat island mitigation strategies.
He is now the president of an atmospheric modeling and research company, Altostratus,
based outside San Francisco.
Taha’s research on the urban heat island effect in Los Angeles has led him to
believe that increasing a roof’s albedo is the silver bullet to lowering urban temperatures.
Taha has seen the benefits of adding plants, but on the ground rather than the roof.
“Just adding plants and trees on the ground can also help make a big difference in the
urban heat island effect,” he says.
With several conflicting research results it’s apparent that the perfect roofing
strategy isn’t exactly black and white, or green and white for that matter. To add to the
option mix, new roofing technologies are being developed to cut down on cooling costs.
11
One of those is a state-of-the-art protective roof coating designed at Hyperseal
Inc., based in Palm Desert, California.
The firm’s cool roof coating called “Hyperglass Cool Top Coat,” was invented by
a retired Air Force colonel who had engineered coatings for jet fighters. It’s made from
acrylic-based paint that’s mixed with hollow glass microspheres. “That’s what gives it
the reflectiveness,” says Allison Kiessling, a Hyperseal spokeswoman. “It’s been shown
to reduce cooling costs by up to 50 percent.”
A hollow glass microsphere is just a fancy way of describing a tiny hollow glass
bead. Thousands of the tiny glass beads mixed into the special paint make the coating
highly reflective.
“We’ve got a product that could become the new standard in roofing,” Kiessling
says. “But it’s new, so obviously we still are in the testing phases to see how long it will
last.” The manufacturers believe it could last up to 30 years.
Hyperseal’s products are gaining popularity. Several Wal-Mart stores in Southern
California are resurfacing their black parking lots with another Hyperseal product called
“Hyperflex.” It’s made from recycled rubber and hollow glass.
The same product can also be used on roof tops before the Hyperglass top coat is
applied. “Adding the two different products can also greatly increase the roof’s life, as
well as cut down on energy costs,” Kiessling says.
At 20 cents per square foot, Hyperglass is considerably cheaper than a green roof.
But planners need to weigh the higher green roof costs with the key environmental
benefits they provide, including preventing storm water runoff.
12
Stormwater management is a critical problem in many cities. Buildings, streets
and parking garages create impermeable surfaces that allow billions of gallons of
rainwater to wash away rather than soak into the ground. This results in polluted runoff,
flooding and, in some cases, inoperative sewage treatment plants. Title IV of the EPA’s
Clean Water Act, states that cities must develop strategies to mitigate that runoff since it
pollutes waterways and the coastal zones.
The EPA’s Nonpoint Source Management Program allows cities to apply for
grant money for nonpoint source implementation projects, including financing for green
roofs. However, Los Angeles County and City have yet to be awarded any grant money
that would go toward installing a green roof.
“It’s a shame more people don’t take advantage of the money out there that could
help fund a green roof,” Miriam Figueroa says. After spending two years studying green
roofs in a semi-arid climate, Figueroa published her USC Architecture master’s thesis on
the benefits of green roofs in Southern California.
“If you think about if all the roofs were covered in greenery, how nice it would be
to look out your office and see a green roof below your window,” Figueroa says. “Seeing
green has a calming effect, at least it does for me.”
Figueroa’s green vision of Los Angeles might be realized with smart planning.
Technology can help resolve the question of how and where to build sustainably.
“What do you do if a building is partly shaded by other buildings and partly
exposed to the sun?” asks Anupam Jain, at USC’s School of Architecture. Jain, who is
pursuing a master’s degree in building science, is currently working on developing
software called “GeoDec” or Geospatial Decision Making. GeoDec not only uses
13
satellite images of cities and neighborhoods, but data can also be input into the software
to model plans for a new building or a retro-fit design.
Researchers at USC’s Viterbi School of Engineering have been developing the
software for several years. The multidisciplinary team draws on resources from other
departments, including the School of Architecture.
“Think of it as GoogleEarth on steroids,” Jain says.
The developers of GeoDec want to enable architects to place 3D digital project
models into a larger 3D model of a city such as Los Angeles. When they do so, perhaps
in the next two years, the software will compute how much sunlight reaches each
building at different parts of the day and year.
“It could help planners and architects decide if the building they are working on
would benefit more by installing a green roof, or by using some other mitigation
strategy,” Jain says. “In some cases, a cool reflective roof might be better suited for the
building.”
Though GeoDec is still in the design phase, the military also has expressed
interest in the software because of its potential use for security purposes. “It also
provides instant feedback, so if there’s a crisis the software could be critical in
developing an evacuation plan for a city,” Jain says.
Whether used for security purposes or building designs, the future of planning
seems to rest in 3D modeling software. “We need to be more informed with our
decisions before we throw up a building and we need software to inform us,” Jain says.
“It’s a question of awareness, education and knowledge.”
14
Jain believes technology will not only show us where to build, but also where not
to build. “By using modeling software we could find out that a green roof would be a
waste of money in some cases,” he says.
Several U.S. cities are already taking urban greening initiatives to a higher level.
“Chicago has provided a good model for other cities,” Kalkstein at the University of
Miami, says.
The Windy City has reinvented itself as a green city by requiring a green roof on
any project that receives city assistance. In addition to mandates, the Chicago
Department of Environment offers incentives, such as a density bonus for green roofs in
its central business district which allows developers to build more units than are normally
allowed on a piece of property.
By comparison with Chicago, the Los Angeles area would appear to be falling
behind.
“It seems most of L.A. is behind on urban greening, with the exception of places
like Santa Monica,” Tom Tindall says, director of internal services for Los Angeles
County. “But we aren’t too far behind, though, in some other energy-saving initiatives.”
All county-owned buildings have replaced incandescent light bulbs with energy-
efficient LED light bulbs. Officials also ditched their inefficient HVAC cooling systems
and installed new motors on air conditioning systems to cut back on cooling costs.
Since 1994, the county has spent about $50 million on energy reduction strategies
and has saved about $110 million. “I would say that’s pretty progressive,” Tindall adds.
15
Perhaps the county’s new $68 million data center, set to be completed by 2011
and topped with a green roof, is evidence that parts of Southern California are moving in
a greener direction.
The data center, which will house bulky heat-producing main frame computers, is
expected to benefit a great deal from its green roof. “It’s going to cut back on the cooling
costs of the center, and another plus is that we’ll attain a Silver LEED standing,” Tindall
says.
A major incentive to install a green roof is achieving a LEED certification. The
Leadership in Energy and Environmental Design (LEED) Green Building Rating System
was designed by the U.S. Green Building Council in Washington, D.C. It manages a
certification program that sets parameters as well as provides people with a way to
measure their building’s energy efficiency.
A building can attain one of four levels of certification based on several
categories, such as water efficiency and energy conservation. The LEED rating system
was recently updated for 2009, with a 100 point system (as well as 10 potential bonus
points). Within this range, a building can earn a Certified, Silver, Gold or Platinum
standing.
Beginning in 2002, all non-residential building projects 7,500 square feet or larger
in the City of Los Angeles have been required to achieve LEED standards. Since then, a
number of LEED-certified buildings have been constructed in Los Angeles, including fire
and police stations, libraries, and animal shelters.
16
Though LEED has set the standard for green building design, some question
whether the system is enough incentive for developers to improve their efficiency in
design.
Jain, at USC, disagrees and believes tenants are aware of a building’s energy
efficiency. “If you are a developer and you’re building a LEED certified building
downtown, it’s much easier to get tenants if you have that LEED standing,” Jain says.
“And that is a huge financial incentive for developers.”
The Getty Museum, with its Silver LEED standing, is now viewed as more than
just a museum by many visitors. “I think people actually see us in a bit of a different
light now,” says museum grounds and gardens manager Lynne Tjomsland. “We’re a
museum with a sustainable mission.”
The museum attainted a LEED standing for its intensive and extensive green
roofs. “We’ve got a pretty good system going here, between the parking garage green
roofs and light-colored cool roofs and walls,” Tjomsland says.
Through several energy reduction strategies, including extensive motion lighting,
the Getty Museum has reduced its energy costs by nearly 10 percent and its water use for
irrigation by 33 percent, saving the museum $500,000 per year, she said.
The museum’s impressive green roof installations didn’t come cheap. “Our
budget it pretty flexible,” Tjomsland says, which is likely the reason the museum was
able to install more than half a dozen different green roof sections, costing hundreds of
thousands of dollars.
17
The average homeowner or cost-challenged developer may not have the resources
of the Getty Museum. But financially-strapped developers needn’t be discouraged
because a low-budget roofing plan seems unattainable. It merely requires research.
The Natural Resources Defense Council’s Santa Monica office, deemed the gold-
standard in sustainable building design, attained a Platinum LEED standing in 2004 for
several reasons, including a cool roof as well as photovoltaic cells which produce 20
percent of the building’s energy.
The office, an environmentalist’s dream work-space, is furnished with chairs and
desks made from only recycled materials, floors composed of wood from only
sustainable or fast-growing forests and water conserving toilets. The building’s on-site
grey-water filtration system recycles water from sinks, showers and rain-water cisterns
that would otherwise end up in the sewage system.
While the total construction costs of the entirely retro-fitted building topped out at
more than $5 million, likely due to the costly nature of recycled materials, isolated parts
of the retro-fitting can be simulated in other homes and office buildings.
“We hope people will come and see what we’ve done, and take away an idea with
them, whether it be a white roof, solar panels or our cistern system,” says Spencer
Campbell, NRDC senior development associate. “They probably won’t be able to do
everything we’ve done, but if they come and see how things work, they will hopefully be
more inclined to make a sustainable change to their home.”
Perhaps these examples of high-profile buildings, fitted with solar-reflective as
well as vegetated roof-tops, indicate that we are on our way to understanding something
18
above our heads needs to change, otherwise we’re in for an expensive and wasteful
future.
Supporters of sustainable living and design believe change can happen, though it
will take time. “Well, it’s not going to happen overnight,” Jain says. “It’s a larger
community-understanding issue, as well as a development issue.”
Devising a plan to change the rooftop landscape of a city might seem like an
insurmountable task, but as Jain points out, change can happen if each homeowner,
building designer, planner and architect decides to make the necessary small changes
which, in turn, will lead to a large city-wide transformation.
Perhaps the only change necessary is one of perspective. If every person would
take a moment to look up, maybe he or she would see the answer to a healthier future is
just up on the roof.
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Abstract (if available)

Abstract The energy crisis, global warming and the rising temperatures in cities: these are problems that are becoming more salient in the United States. And now with a new energy-conscious president, the idea of a fresh start finally seems plausible. Most of the solutions are not new: cut down on carbon dioxide emissions by driving less, use public transportation and find alternatives to oil. However, it is somewhat rare to hear about other innovative and sustainable practices that cut down on CO2 emissions. Though green roofs have an obvious aesthetic function, the connection between installing vegetation on roofs and CO2 reductions is not as widely understood. Green roofs help reduce CO2 emissions because vegetation, as opposed to hard concrete, absorbs relatively less sunlight, which reduces internal temperature of the building and the surrounding air. By reducing the building's temperature and mitigating the "urban heat island" effect, less energy is required to cool the building. While green roofs provide many needed benefits, cool roofs have also shown to decrease building energy consumption. Cool roofs, or roofs painted white have been a popular cooling technology since the Ancient Greeks used them to keep their homes cool, but more recently roofs have fallen out of the energy debate. The current popular way to decrease energy usage is primarily centered on changes inside the home -- installing LED light bulbs, more efficient appliances and cooling systems. But there is an easier and cheaper way to cut back on energy costs: just look up to the roof.

Linked assets

University of Southern California Dissertations and Theses

Asset Metadata

Creator Petroka, Katelyn Mary (author)

Core Title A roofing revolution: refocusing on rooftops can reduce energy usage, clean our cities and create a more sustainable future

Contributor Electronically uploaded by the author (provenance)

School Annenberg School for Communication

Degree Master of Arts

Degree Program Journalism (Print Journalism)

Degree Conferral Date 2009-05

Publication Date 04/30/2009

Defense Date 04/01/2009

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag cool roofs,Energy,green building,green roofs,OAI-PMH Harvest

Language English

Advisor Pryor, Lawrence (committee chair), Bernstein, Mark (committee member), Celis, William (committee member)

Creator Email kmpetroka@gmail.com,petroka@usc.edu

Permanent Link (DOI) https://doi.org/10.25549/usctheses-m2157

Unique identifier UC1311576

Identifier etd-Petroka-2842 (filename),usctheses-m40 (legacy collection record id),usctheses-c127-225715 (legacy record id),usctheses-m2157 (legacy record id)

Legacy Identifier etd-Petroka-2842.pdf

Dmrecord 225715

Document Type Project

Rights Petroka, Katelyn Mary

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Repository Name Libraries, University of Southern California

Repository Location Los Angeles, California

Repository Email cisadmin@lib.usc.edu