Will green roofs be the next hot trend?
By Cliff Bowden • Bankrate.com
If the term "green roof" evokes an image of a few potted plants arranged tastefully on the top of a building, then the time seems ripe to rethink that definition. Green roofs may be the next hot trend to cool down the urban landscape and lower the cost of controlling temperatures in the average suburban home.
Green roofs are generally categorized by one of two forms. Extensive green roofs, also known as eco-roofs or low-profile roofs, are made with a few thin layers of soil, are lightweight, relatively less expensive, and require very little maintenance. Extensive green roofs are the correct choice, the experts say, when the primary desire is for an ecological cover with limited human access.
Intensive or high-profile green roofs, on the other hand, look like traditional roof gardens because a much wider variety of plant material is usually included. They have soil depths ranging from 8 to 12 inches, with growth that can extend upward of 15 feet. They can include such architectural features as waterfalls, ponds and gazebos. Their construction and maintenance is much more costly.
A feeling of home
When Focus Development planned the Church Street Station Condominiums near Northwestern University in Chicago, a garden roof where unit owners could get away from the hustle and bustle of daily life was part of plans to create a place buyers would call home. To make it, Chicago's American Hydrotech used what it calls time-tested components so that the garden would bloom and flourish season after season.Photo courtesy American Hydrotech, Inc.
Living data center
The Living Roof on Hamerschag Hall at Carnegie Mellon University was designed for ongoing research on the benefits of storm-water management and energy conservation for buildings housing classrooms, labs and administrative offices. A ''datalogger'' is positioned in an office within the building for ease in downloading figures on such variables as thermal fluctuations and the amount and positioning of water runoff.Photo courtesy G.R.E.E.N. research co-operative, Southern Illinois University Edwardsville
"You must water them for the first 10 weeks or so," Retzlaff says. "They have to get established, just like any other garden. And at minimum, you need to add some plants, fertilize and weed a couple of times a year."
Before establishing a green roof, consumers need to have some sense of what they want from it beyond the vague notion that they're good for the environment.
Retzlaff says Ford Motor Co. has a 10-acre extensive green roof in Dearborn, Mich., that remains the largest in the U.S. "It has a 2-inch depth, so they have to irrigate it. They catch storm water in retention ponds and irrigate with that."