ICU Rooftop Garden
Germany has hundreds of examples of green roofs. In Tokyo, there’s a mandate that building vegetation must constitute 20 percent of new construction.
Green roofs make sense because, in addition to offering an obvious aesthetic benefit, they …
- help control storm water run off
- reduce energy costs for cooling and heating
- can double the service life of a roof
- help reduce sound reflection and transmission
- create a habitat for birds and other small wildlife
In the summer of 2007, St. Mary was set to replace the waterproofing membrane of the 5,000-square- foot roof over the Radiology Department. The Community League seized this opportunity to recommend the development of a green roof and received an enthusiastic response from the administration.
The project was made possible in part by a grant from The Reinvestment Fund and its Sustainable Development Fund, which was established by the Pennsylvania Public Utility Commission to offer innovative financing in the area of renewable energy. While the fund has supported wind and solar projects, the green roof grant was a first.
The balance of the funding was provided by The Community League.
Unlike the two predecessor Healing Gardens, which invite visitors, patients, physicians, and colleagues to stroll and linger, the St. Mary green roof is designed as a purely visual experience, transforming the 5,000-square foot roof over radiology from a visual liability to a metaphorical garden intended to provide solace to all. The panorama above shows the completed green roof as viewed by patients, visitors, physicians, and colleagues. It is surrounded by ICU, MedSurg, CBCU, and oncology units, including patient rooms, on the two floors above the level of the green roof.
Green roofs are essentially of two different types: 1.) the “extensive” roof has six or fewer inches of growing media and can be planted with sedums, herbs, meadow grasses, and perennials; 2.) the “intensive” green roof has deeper growing media and can support complex landscapes.
The St. Mary green roof is designed and built as a variation of Roofscapes Type II Roofmeadow® Aromatic Garden system – a very thin extensive roof with only 3 ¾ “ of growing media. The system has a root barrier to prevent the underlying waterproofing membrane from being damaged by plant roots and an intricate draining system to efficiently manage run-off even in the case of a heavy deluge.
The designer’s inspiration was a weaver’s loom that symbolizes the relationship between St. Mary and the community. For example, the warp (thread stretched on a loom) is represented by rubber paver tiles of 100% post-consumer recycled rubber extending outward from St. Mary to the community.
The weft (waves that run perpendicular to the warp) symbolizes a life force extended from patient to patient, room to room, and its reflection permeates the windows surrounding the green roof. The weft is formed with white pebbles that are glued to a substrate to prevent them from moving in high winds.
The roof was planted mostly with sedums (cuttings and plugs), following the contours established by the pebble tiles. A total of 55.2 cubic yards of Rooflite lightweight growing media supports the plantings on this roof. Green roof growing media, such as Rooflite, is more water-absorbent than soil and has about 50 percent less weight.
As the green roof matures, the weaving effect will be emphasized by various shades of sedum with flowers of different colors that bloom at several times of the year.
The color of the sedum foliage ranges from green to red/orange to blue/grey with yellow, white and pink flowers. Bluish foliage sedums were installed mainly as plugs, since they do not root as easily. Grasses are planted near the air handlers where the growing media is six inches deep.
Sedum becomes dormant from lack of water, and then quickly greens up after receiving adequate moisture. Metaphorically, this process is intended to inspire patients to look for hope and the end of an exhausting illness.
Explore Our Gardens: