Over the past few years, a sweeping construction boom has rendered U.S. cities ever denser, but there’s one type of urban space that’s still an untapped resource: rooftops.
Sure, every city lover can name a handful of rooftop patios with great views or a favorite rooftop hotel pool. But for the most part, roofs remain in the domain of the squarely utilitarian, home to chimneys, air ducts, and satellite dishes. That can change.
According to Steven Peck of the Toronto-based non-profit Green Roofs for Healthy Cities, “The roofscapes of our cities are the last urban frontier—from 15 percent to 35 percent of the total land area.” They can offer much more than just a pretty view.
For example, rooftops can provide room to grow food, build affordable housing, and green our cities, to name a few. And making roofs more sustainable—installing “smart surfaces” like green roofs and solar panels—could be a cost-effective design solution that could save cities millions, and even billions, of dollars.
Below, check out eight ways urbanites are transforming roofs from empty dead spots into spaces for innovation.
A common way to transform an unsightly rooftop is to add greenery. But vegetation can do far more than create an urban oasis. Green roofs covered in plants can reduce stormwater run-off, lower cooling costs, and combat the urban heat island effect.
One compelling example comes from Vietnamese architect Hung Nguyen, who designed a roof pavilion covered in plants with air-purifying properties. Other homeowners use drought tolerant, low-maintenance plants like sedum to create a green roof that can withstand even harsh winter climates.
The potential of green roofs have made them a hot-button issue in cities; in November 2017 Denver, Colorado, voters passed an initiative that requires any new construction with a gross floor area of 25,000 square feet or greater to include a living roof with vegetation and/or solar panels.
Larger rooftop gardens can also become farms. In New York City, Brooklyn Grange runs rooftop farms in Long Island City, Queens and the Navy Yard in Brooklyn, producing tens of thousands of vegetables a year that are sold directly to urban restaurants and greengrocers.
In Paris, urban farming is flourishing after the government launched Parisculteurs, a program that wants to cover the city’s roofs and walls with 247 acres of vegetation by 2020. In Chicago you’ll find the world’s largest rooftop greenhouse, a 75,000-square-foot facility set atop an old factory. Operated by Gotham Greens, the farm uses a state-of-the-art hydroponic system with a yield that rivals that of a 50-acre farm.
Beyond transforming unused space into eco-friendly agriculture, rooftop farms also reduce transport costs by growing products in close proximity to metropolitan areas. These farm create a more bio-diverse ecosystem in cities, as well, attracting birds, insects, and butterflies.
Gwen Schantz, founding partner and COO of Brooklyn Grange, told Curbed, "I feel like what we’re doing is part of the food movement," she observes. "But it’s also part of the movement to bring green space back into the city and to improve the health of the plants and the animals, but mostly the health of the people here." Head over here for more on rooftop farming.
In dense cities with high-priced real estate, rooftops could be the final frontier of affordable housing. Berlin-based architects Simon Becker and Andreas Rauch launched Cabin Spacey to help solve the urban space crunch by building tiny homes on some of Berlin’s 55,000 unused roofs. Becker and Rauch’s cabins—still in the concept stage—can house up to two people in 250 square feet, and can run fully off the grid thanks to solar panels attached to the roofs.
In London, PUP Architects created a tiny dwelling that looks like an air duct as a playful nod to the planning rules that allow rooftop mechanical equipment to be installed without permission. Called H-VAC, the design was the winning entry in the inaugural Antepavilion competition, which explores innovative and alternative ways of living in the city—especially on rooftops.
And just recently, Homes England agreed to a £9 million funding deal with Apex Airspace Developments to deliver rooftop homes through offsite construction across five different neighborhoods in London. Half of these homes will be affordable.
Another way cities are trying to take advantage of wasted roof space is to use them as recreational areas. Rooftop pools have long been a staple of high-end hotels and condos, but larger gyms, soccer stadiums, playgrounds, jogging paths, and even open-air cinemas are becoming more common. In Miami, an apartment complex has rooftop tennis courts and a track, while the 30-acre Paramount Miami Worldcenter—set to be completed in 2019—will have a soccer field over an office building.
In Tokyo, Japan, people can play soccer on the roof of the Shibuya Hikarie skyscraper, while in Osaka, a 1000-foot astroturf track stretches across multiple roofs at Morinomiya Q’s Mall Base shopping complex.
Along with soccer stadiums and playgrounds, we may see more urban campsites on rooftops in the future. Kampgrounds of America (KOA) recently envisioned what camping could look like in 2030 in five different ecosystems—including cities. These futuristic renderings are far from a reality, but they show that rooftops offer up a place where city dwellers could camp under the stars right in their own backyard. See more, this way.
Chicken coops and apiaries
A natural progression from gardens and farms, chicken coops and beehives are another innovative addition to city rooftops. Chickens can be raised in relatively small spaces—each hen only needs about four square feet—and can provide a whole apartment building with fresh eggs.
Rooftop chicken coops have already made it onto some Seattle apartment buildings and New York City hotels, and the Madison, Wisconsin, Children’s Museum turned their rooftop into a Frank Lloyd Wright-inspired exhibit with chicken coops. Likewise, beehives on hotels and skyscrapers can provide businesses with honey for cocktails, food, and spa treatments. It’s the ultimate “locally sourced” honey.
Rainwater collection systems
As the first point of contact—known as the catchment area—for rainfall, roofs can be an optimal way to harvest rainwater. This age-old method of collecting water may not be as common in the United States as it is in developing countries, but it’s becoming more popular.
Especially in drought-afflicted states, harvesting rainwater can be an excellent way to retain stormwater runoff, reduce pollution, and reuse hundreds of millions of gallons of rainfall every year. While not fit for drinking water, harvested rainwater can be used for non-potable purposes like yard watering and toilet flushing.
Philadelphia, Pennsylvania, has incentivized rain collection by imposing “stormwater charge” on properties based on the size of impervious space on the property; homeowners can lower their stormwater charge by adding more green space.
The most obvious and common use of rooftops is still solar power. It makes sense; unlike many city streets, rooftops have unobstructed access to sunlight and enough space to make larger-scale solar panel installations feasible. And while the idea of solar panels on roofs may not seem innovative, the industry is going through big changes.
For one, new rooftop solar tiles from Tesla look nothing like the solar panels of yore. The Tuscan glass tile tiles and textured glass tiles look like conventional roof tiling, which could mark a new age of rooftop aesthetics. Other startups are chasing similar concepts.
Elsewhere, the solar industry is trying to make urban rooftop energy a community endeavor. Around 10,000 Australian homeowners are participating in a pilot program testing the world’s first open market for monetizing rooftop renewable energy and storage. And in Brooklyn, a new energy startup links up neighbors who have solar panels with those who want to buy clean energy, creating the Brooklyn Microgrid.