Living roofs have become all the rage, greening up New York City
Coming to a brownstone near you: The living roof, the newest must-have in urban gardening, writes Michelle Higgins of The New York Times
Over the past decade, acres of living roofs have appeared in New York City, as commercial building owners have transformed their rooftops into meadows of wildflowers, sprawling beds of sedum and even vegetable farms, reaping the environmental benefits. Now individual homeowners — those lucky enough to have a roof or terrace that can accommodate a patch of dirt — are beginning to follow suit.
“About 1,200 buildings in the city have green roofs, covering almost 60 of the nearly 40,000 total acres of rooftops,’’ said Michael Treglia, an urban spatial planner with the Nature Conservancy.
Susan and Neil Whoriskey have one of those green roofs in Brooklyn Heights. Last autumn, the couple hired Inger Staggs Yancey of Brooklyn Greenroof to install a sedum garden on a 250-square-foot section of their town house roof.
“We wanted to capture as much of the rainwater as possible before it ended up in the sewer system and we thought it would look nice to have plants in place of a drab-looking roof,” said Whoriskey, a lawyer who represents non-profit companies. “It’s really kind of magical to have such lushlooking plants that require literally no attention.”
The upside of landscaping your roof is well documented: Green roofs not only retain rainwater, decreasing sewer discharge, but they also help reduce air pollution.
“New York City’s sewers are all ancient and one just collapsed on our street last summer,” Whoriskey said. “With the crazy rainstorms we’ve been getting lately, it would make a big difference if more people had green roofs. Even if you don’t want to give up your entire roof, you can still do a partial roof like we did.”
But what about the downside? We talked to New Yorkers who have green roofs — and some who specialise in installing them — to find out what it takes to plant and maintain a living roof.
How hard are they to install?
Planting a living roof is more involved than just putting out a few flower pots, so unless you have professional experience, it is not the sort of thing you should attempt on your own.
On top of the outermost layer of your roof (or the waterproof membrane, as it is known in roofing parlance), a protective mat or layer of insulation is laid down. That is followed by a root barrier (to keep the plants from growing down into your bedroom), a drainage layer, soil and, finally, the plants.
Sedum, that spongy, low-growing succulent, is favoured by many green roofers in the Northeast for its short rootsand drought-resistant properties.
“Sedum is so resilient that it will not need to be replaced each spring,” said Yancey of Brooklyn Greenroof. “It actually lives through each harsh New York winter by going dormant and turning a reddish-brown colour. In spring, it bounces back better than ever, having rested and recharged over the winter. And because we always plant a mix of different sedums, it flowers in different colours, over an extended period of time, all through the summer and into autumn.”
How much will it cost?
The upfront costs of planting a living roof can be considerable, from about $10 a square foot to $40 a square foot, depending on the size and complexity of the project.
Over time, however, green roofs can reduce energy and maintenance costs by protecting your rooftop and building equipment from excessive exposure to sun during the warmer months and increasing heat retention during the cooler ones.
Andrew Franz, an architect in Manhattan, installed an expansive living roof for clients with a three-bedroom Tribeca penthouse.
The layers of soil and vegetation created an “insulated building envelope” that significantly reduced their heating and cooling costs, said Franz, who worked with Plant Specialists, a landscape consultant, to develop and install the green roof.
“The apartment is now 10 degrees warmer in the winter and 10 degrees cooler in the summer,” he said.
Is it safe to pour all that dirt and water on the roof?
Again, consult the experts. Before turning your roof into a grassy knoll, you should talk to an engineer to make sure it can support the additional weight — not just the dry soil and planting layers, but the extra load involved when it is saturated with water.
And that is not the only water-related consideration. “It is a real pain to repair roof leaks underneath a planted green roof, because you have to dig it out,” said John Heidenry, a managing partner at Red Bridge Homes, in Hoboken, New Jersey.
Most green roof installers recommend planting only on new or recently renovated rooftops, but even then there can still be problems. When a leak was discovered at a twofamily town house in Hoboken that Heidenry built with his partner, Peter Slifirski, the 960-square-foot living roof had already been planted — with three pallets of topsoil, eight evergreens and nearly 3,000 sedum plugs.
An errant wire from the outdoor speaker system had punctured the roofing membrane near one of the trees. Without the green roof, fixing “it would literally have been a 10-minute job,” Heidenry said. “But it took a full day with all the soil and the trees needing to be removed and replanted.”
There are also logistics to consider: For instance, how are you going to haul all those 50-pound bags of drainage rock up there? That was a dilemma Lory Henning faced when installing a green roof on the two-family brownstone she shares with her wife, Cindy Keiter, and three cats, a project she chronicled on her blog, Project Happy Life.
The couple rented a crane to hoist six big bags of dirt and three pallets of sedum tiles up to the roof. But other materials, including 164 bags of drainage rock, arrived after the crane had been returned.
Henning, who worked as a stage manager for Blue Man Group and is skilled in woodworking and metalworking, designed a gantry to haul the heavy things up through a roof hatch.
The effort and the sore muscles were worth it, said Henning, who is producing an off-Broadway play with Keiter: “I’m up there almost every day. I use it as a space to relax and contemplate big decisions, as a place to experiment with plants and design, and obviously as a place to harvest food.”
Not only that, their heating bills went down to about $142 a month in the winter, from more than $350, she said, “and I believe the upstairs apartment is cooler in the summer now as well.”
What about resale values?
A living roof, real estate agents say, tends to boost a property’s value.
“I normally value outdoor square footage at somewhere between a quarter and a third of the value of indoor square footage, depending on its quality and size,” said Heather McMaster, an associate broker with Corcoran, who just listed a one-bedroom in Prospect Heights, Brooklyn, with a 350-square-foot private roof deck surrounded by the building’s living roof, for $799,000. “With this particular property, I’d value the outdoor space on the higher end.”
Camilla and Karthik Sankaran’s investment in their roof also appears to have paid off. Before they had a living roofinstalled atop their Park Slope brownstone, “our roof looked like any other white-painted brownstone roof,” Camilla Sankaran said. “Now it’s lush and green, with flowers blooming in the spring and summer.”
“An oversized window opens onto a small deck overlooking the living roof,’’ she said, which “is like having our own little meadow.”
Buyers seem to agree. The Sankarans bought their brownstone six years ago for less than $2 million and after a renovation that included installing the green roof, they recently put the house on the market for $4 million. They now have an accepted offer.
We thought it would look nice to have plants in place of a drab-looking roof. NEIL WHORISKEY BROOKLYN HEIGHTS RESIDENT