For many homeowners, urban living is the only way to go. There’s easy access to stores, restaurants, cultural attractions ,and the energy and hustle and bustle of city life. There’s only one thing missing: a quiet place to relax outdoors. For those with the right building and the proper budget, the answer is a rooftop terrace or garden.
Chicago Specialty Gardens (www.chicagogardens.com) has been helping homeowners in the Windy City realize their rooftop garden dreams for about eight years. Recently, the firm had an opportunity to work on a project that involved transforming three different rooftop spaces.
The project took place at a large (approximately 10,000-square-foot) single-family residence in an upscale neighborhood. Bill Mitchell, rooftop division manager with Chicago Specialty Gardens, says, “The home was complete when the client contacted us, and there were three outdoor terrace spaces: one off of the kitchen on the second floor, another that was partially enclosed off the fourth floor, and then a main rooftop terrace above the fifth floor.”
While the project was unique in many ways, the homeowners’ desire for outdoor living space in the city is common. “What’s happened a lot in Chicago is that the higher-end, single-family construction typically builds pretty much lot line to lot line, so they end up not having any outdoor space, or a space that’s so sunken and dark that it’s really unusable,” says Mitchell. “So, we hear from a lot of clients who want to use their roofs for outdoor living space.”
The residence was constructed specifically to accommodate outdoor terrace construction, which is not the case with all rooftops, says Mitchell, and sometimes structural work needs to take place prior to constructing rooftop gardens. When Chicago Specialty Gardens arrived at the home, the homebuilder had already outfitted the terraces with 2-by-2-foot concrete pavers. “There was water and electricity up there, as well, but, otherwise, there really wasn’t anything garden-like or architectural or landscaped about the terraces. They were just sort of hard spaces,” Mitchell recalls.
The concrete pavers were set on plastic pedestals, which is how Chicago Specialty Gardens typically begins its rooftop terrace work, whether the finistitle surface is going to be deck panels or pavers. “As much as we can, we try to build everything in a modular fashion. That way, in the future, the pedestal can always be pulled back up to access the roof,” says Mitchell. The company uses Tile Tech pedestals, but Mitchell says there are several brands on the market. “You can adjust the height depending on the pitch of the roof in order to keep a level surface,” he says, adding that the goal is to create a terrace space that looks permanent, but can be easily taken apart for repairs. Most plants are installed in containers, which helps keep things modular.
When Mitchell first surveyed the project he noted the type of access available to the terraces, looking at where materials could be delivered, door sizes, ease of entry, etc. “We need to figure out how we’re going to get materials up there,” he explains. “In this case, we used a hoist mounted on a set of scaffolding and cantilevered over the edge with a winch cable dropped down.” Having a hoist system set up for the duration of the project offered flexibility.
The residence had a built-in elevator, which was also used to bring materials up to the terraces. In cases like that, the Chicago Specialty Gardens crews are careful to protect interior living spaces against damage. Mitchell says, “We usually put down protective drop cloths and plastic and tarps, and we usually wear shoe booties.”
The design of the terraces was assembled based on the homeowners’ desires and planned uses for the space, while keeping within the structural limitations of the roofs and the types of plants and materials that can survive in exposed rooftop environments.
On some rooftop projects, Mitchell says it can be a challenge to explain the limitations of landscaping these elevated spaces to clients, whosea vision for the spaces might be based on a ground-level landscape. “I think what’s often overlooked is that there’s no soil up there to work with. Any soil you use has to be a special, light soil mix.” The soil the company uses is highly organic.
Many people also aren’t aware initially of the added costs involved with rooftop versus ground-level landscapes. Mitchell says, “It’s a lot of hand work.” There’s also usually not space to store materials, so the job has to be sctitleuled and staged in steps. “If you put all the soil up on the roof in the beginning, you’d never be able to move,” he says.
The design called for the removal of some of the concrete pavers to soften the terrace spaces. “The spaces were so big, the rooftop was about 2,000 square feet and the other patios about 400 square feet each, that they really could afford to give up some of that paver space,” explains Mitchell. “Where we removed the pavers, we put in pebbles with aluminum trim.”
In one area, a commercial golf putting green surface was put down. It is also used as a play area for the children. The Chicago Specialty Gardens’ fabrication shop created a plywood frame beneath the area that offered subtle movement to add challenge. “We have a carpentry/fabrication shop where we try to construct things to cut down on the amount of on-site construction needed,” says Mitchell. “In our shop, we work with aluminum and build all the wood components that we use, such as benches and trellises, and we also cut out panels and decorative screens out of 3Form, a resin material with different grasses sandwictitle into it. It’s a very beautiful, eco-friendly material.”
A crane was brought in to lift some large trees up to the terraces. “We craned up some 8-foot redbuds. They were put into really nice zinc containers that were handmade in Belgium,” says Mitchell. He and his crew added insulation to the double-walled containers to help keep the soil and roots frozen in the winter rather than thawing every time the sun comes out and damaging the roots in a freeze-thaw cycle.
Chicago Specialty Gardens does provide rooftop garden maintenance services, but Mitchell notes the nature of these installations means they are usually pretty low maintenance, requiring service only every few weeks or even just once a month during the growing season. At the beginning and end of the season, there might be more work required to turn the irrigation system on/off (the company usually installs drip line micro-irrigation systems), or to put in annual flowers or cut back perennials.
On one of the terraces, the crews constructed a shade structure over a dining area. “On the terrace off of the kitchen, the homeowners wanted a place to cook and hang out. On the fourth floor they wanted a lounge area, because it’s covered and they can sit out there even in the rain. On the rooftop, we did a combination of a lounge and dining area with the golf putting green,” says Mitchell.
Mitchell says that while there are more landscape construction firms entering this arena, it’s still a fairly niche market. “And, there’s still a lot of flat rooftops in the city. With outdoor living space at a premium, there’s still a good market for it.”
Patrick White is a freelance writer based in Middlesex, Vt. Over the past 13 years he has covered hundreds of landscape installation and maintenance projects around the country, with an eye on documenting the tools and techniques used and spreading the word about innovative ideas. He is always on the lookout for unusual stories and cutting-edge installations.