Patches of green, living things are pretty rare in the city. Outside of Central and Prospect Parks, New Yorkers don’t generally get a lot of leafy goodness in their lives—not all of us have a key to Gramercy Park, after all. Some co-op and condo buildings—and some whole neighborhoods—are trying to break up the grayness with greenness, however. They’re doing it on their rooftops, in their courtyards and alleyways, and turning entire unused lots into community gardens. The city was once known as the concrete jungle—but those days are over. Green is here to stay.
Greening Your Rooftop
Inthe suburbs, houses are built on green spaces, yards of a half-acre or more covered with grass and landscaping. Space of that kind is a luxury that doesn’t exist in many parts of New York—especially Manhattan. What all residential buildings do have, however, is a roof—and thus the roof is one of the most popular places to set up a green space. But how do you take a black roof and make it green?
“When you’re working on a rooftop, the most important thing is to understand the weight load that the rooftop can take,” says Kim Mathews of New York City-based Mathews Nielsen Landscape Architects, which specializes in all types of community spaces. The roof has to be able to withstand the weight of the added soil, grass and other plants, and people up there to enjoy the view.
“If you want to do a rooftop garden, the first thing you have to determine is whether or not the building structure is capable of taking additional loading,” explains Jeff Grob, a landscape architect with Stantec, which helped design the Gil Hodges community garden in Brooklyn. “Once you see that the roof has available capacity, then you can start taking a look at, well, do you want to create a green roof that’s just plants? Or do you want a roof garden that’s plants, and spaces for people to use for recreation, to sit around in?”
A designer ultimately may end up recommending that you put a new kind of roof system that would be amenable to having plantings on top. But most of the time, we’ll bring in trays that are pre-planted and have soil in them, and they go right on top of a protection layer on the roof. And then the drainage in the trays works with the pitch of the roof, to use the existing roof drains for runoff.”