PECO Main Office Building
Philadelphia, PA


Type I - 3.00 inches of media
Type III - 8.00 inches of media

This green roof’s accessibility to the public is its most important feature. To date, nearly 1,000 people have participated in tours and special events on this roof.

In partnership with the Pennsylvania Horticultural Society, PECO co-sponsors public green roof tours that attract architects, developers and engineers’ intent on learning more about vegetated assemblies. These popular and well-attended tours expose countless design professionals and interested citizens to this classic German style green roof technology. The PECO green roof serves as an emblem of Philadelphia’s progressive storm water management policies. Mayor Michael Nutter has recognized the roof as a step forward in his quest to make Philadelphia the greenest city in America. In the effort to encourage a critical mass of enlightened Philadelphians to support the development of urban roof top landscapes, the PECO green roof is proving to be a key player.

The city of Philadelphia is plagued with a serious water pollution problem as the result of a centuries old combined sewer system. The PECO Main Office Building sits on the densly developed Schuylkill River banks in the heart of Center City, and the roof footprint is 95% of the lot area. In an effort to solve the onerous CSO issue and comply with the Federal Clean Water Act, the city is incentivizing green infrastructure as a key solution, with the added benefit of providing additional environmental benefits for the adjacent cityscape. The 8th floor podium roof, covered with more than one acre of vegetation, is visible from the surrounding high-rise buildings and provides a focal point for thousands of Philadelphians.

In order to safely accommodate guests, the roof area used for tours and gatherings is separated from the rest of the expanse by a self-ballasting, ADA compliant railing for pedestrian safety. The railing provides a secure barrier without requiring the attachment to the roof deck or penetration of the waterproofing membrane.

This retrofit project was established with low-maintenance Sedum pre-vegetated mats over a specially formulated lightweight growing media. The cool green Sedum carpet is punctuated by pathways, lit seat walls and native perennial beds located over zones with a higher dead load capacity. These native beds add a dramatic counterpoint to the adjacent Sedum cover. Roofmeadow and PHS closely track the native plants to identify those that are best able to endure the harsh conditions of a windy, riverside rooftop.

The traditional German technology that inspired the design and construction of this roof is proving to be a fountain of inspiration and education for design professionals and corporate developers alike.