Most green roofs are located out of sight and beyond reach, but the future tenants of a residential and retail project now under construction in Philadelphia will get to enjoy a green roof designed to serve as both a garden and a storm-water treatment system.

Photo: Courtesy Erdy McHenry Architecture

A green roof will cap the Radian's street-level shops.

The roof will be located atop the ground-floor retail podium of the Radian, a 154-unit privately owned student housing-complex on the University of Pennsylvania's Philadelphia campus. Ringed by dense plantings of black-eyed Susans and other flowering species, the space is located next to an outdoor dining area.

'Our goal is to make it approachable and put it in people's face so that they understand the environmental value,' says David McHenry, AIA, of Erdy McHenry Architecture in Philadelphia and the project's lead architect. "It's functional, and there is an educational component to it."

The 12,000-square-foot green roof, which covers 20 percent of the Radian's total footprint, was designed primarily to satisfy the city's storm water control regulations. Special drains will capture runoff from impervious sections of the terrace, funneling it into an irrigation system for the plants. Locally based Pennoni Associates is responsible for the landscaping and engineering, while Roofscapes, a green-roof specialist also of Philadelphia, is providing technical assistance.

Although the Radian's developer, University Partners, is not seeking LEED certification, the project's other sustainable features include a prefabricated rain-screen wall-panel system. The facade patterning responds to the varied size of the dwelling units and thus helps reduce the massing of the 14-story tower. Construction is scheduled to finish in August 2008.