The secret to creating new public parks out of thin air: foam

At Cascade Park, a new inexperienced house alongside Lake Michigan exterior of Chicago’s Loop, the sloping grassy hillside and pockets of timber and shrubs belie what’s taking place slightly below the floor. Masking practically an acre of land, the park is a form of landscaped facade. Underneath the few toes of soil that maintain the plantings, the earth provides manner to 3,000 cubic yards of what’s often called geofoam, a light-weight structural materials. That sea of foam blocks sit on a cantilever of concrete holding the park above a still-active community of service roads, beneath. As an alternative of wanting down on these streets, the foam and the landscaped park flip the airspace right into a new chunk of city land, draped over the vacancy.

Geofoam blocks being put in for an MTA venture in New York Metropolis. [Photo: MTA/Flickr]

In tasks throughout Chicago—and in a rising quantity of city facilities round North America—the areas above parking garages and different transportation infrastructures are being reworked into parks and inexperienced areas, seemingly out of thin air. Utilizing classes from Chicago’s expertise topping buildings with park-like inexperienced roofs, designers are discovering new methods to conceal unpleasant city infrastructure with usable city house that requires solely the thinnest layer of precise dust and roots.

[Photo: Dave Burk/courtesy Confluence]


Cascade Park is an instance of how this method is making new public house within the more difficult areas. Developed by Lendlease and Magellan Development Group, Cascade Park is adjoining to a new 37-story residence tower and 47-story condominium. Connecting to the shore of Lake Michigan, the park transcends 55 toes of grade change, carving a steep, but accessible, path between the water and the residences. Opened in August, the park creates a floor ground amenity for each buildings’ residents and the neighborhood (newly dubbed Lakeshore East) at massive.

[Photo: courtesy Confluence]

It’s an method that gives new potentialities for city design, in accordance to Tom Kerwin, founding principal of Chicago-based bKL Architecture, which designed the event that features Cascade Park. The park was enabled by a revision within the website’s general grasp planning: eliminating the primary 5 flooring of every constructing’s chunky concrete storage podiums. Of their stead: open house wanting out over the service roads beneath. This discount in parking allowed more room for the park, which now juts out over these service drives in a seamless growth surrounding the buildings. “It’s actually a new floor aircraft,” Kerwin says.

[Photo: Dave Burk/courtesy Confluence]

The park itself was designed by Claude Comier + Associés of Montreal and executed by Confluence, a landscape-architecture-and-urban-planning agency with 9 workplaces throughout the Midwest. Matthew Unusual, a principal at Confluence, says new supplies are enabling these varieties of parks to be inbuilt unlikely areas, usually with none indication that they’re topping some preexisting infrastructure. Had soil been used for the whole depth, the park would have weighed an unwieldy 3,300 tons. As an alternative, the mixture of geofoam and soil totals a mere fraction at simply 2.25 tons, making it doable to cantilever this house over an energetic road beneath.

“There are some locations the place it’s 3 or 4 toes thick with foam beneath. You’d by no means see it on the floor, however beneath there’s an enormous quantity of foam,” says Unusual. “Every little thing that’s wanted to assist the burden of a construction like that has actually superior technologically over the past three many years.”

Many of these developments have been accelerated by Chicago’s green roof ordinance, which gives incentives to builders who add vegetation to no less than 50% of their buildings’ rooftops. This has resulted in 500-plus vegetated roofs citywide, masking greater than 5 million sq. toes.


The method is getting used to create new sorts of city areas. One of probably the most notable examples sits just some blocks away from Cascade Park at Millennium Park, an enormous inexperienced house and live performance venue, which was built atop a large stretch of discontinued rail traces operating into and thru downtown Chicago.

Confluence has a number of related tasks underway in Chicago, together with a plaza alongside the riverside that floats above energetic rail traces, and a forthcoming 1.5-acre public park constructed over a parking storage throughout from Union Station. Different tasks are underway in Nashville and Dallas.

“They actually characterize this chance to create public house the place there wasn’t any earlier than,” says Unusual. “Locations that have been beforehand parking garages or highways or no matter, all of a sudden now, can grow to be these actually vibrant public areas.”