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Weekly UpdatesSkyland USA LLC produces the only branded green roof media--rooflite[TM]--available nationwide for the green roof industry. Green roofs have been around for centuries in some European countries. The modern green roof movement started in Germany in the 1960s, and is gaining notice as government officials tout sustainability initiatives.
Green roof systems can reduce heating and cooling costs, increase the life span of a traditional roof, reduce storm water run off, filter pollutants and carbon dioxide, insulate for sound and can be used to grow trees and gardens. Green roofs are used in place of conventional roofs and require a specialized roofing system. They are installed most often on warehouses, big box stores, college and university buildings, museums and government structures.
There are two basic types of green roof systems. One is a built up system. As with a conventional roof design, a waterproof membrane is first placed on the roof surface. Next a drainage layer, then a filter cloth and finally the lightweight growing medium and plants are applied. The other is a modular system whereby the modules are filled with growing media, planted and grown out on the ground prior to placement on the roof.
Each system has its pros and cons. There are three basic types of green roof design. The first and most common design is called an extensive green roof. This design uses a very shallow depth of growing media (3-6 inches) and the typical plant selections are Sedums, an alpine type of succulent plant, low growing and able to withstand extreme weather conditions typical on a roof surface. Most green roofs are of the extensive design and work best when the area of the roof is the same dimension as the area of the building, such as a warehouse.
The second design type is an intensive system with a depth of media from six inches up to an unlimited depth. With an intensive system, anything is possible in terms of plant selection; trees, shrubs, perennials and everything in between can be grown. In a sense there is no difference in plant design options for an intensive system when compared to a ground level garden. The third design option is called a semi-intensive system, and as the name implies, this is a blend of the extensive and intensive designs.
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Lastly, the limiting factor for a green roof design is the load rating of the roof itself considering that not only does the roof have to have the ability to hold the green roof system (typically an additional 20-30 pounds per cubic foot for an extensive system) but additional factors such as snow load, excessive rain fall amounts and HVAC systems. The bottom line is that before considering a green roof installation, a qualified building engineer should always be consulted.
Laurel Valley Soils
Laurel Valley Soils (LVS) got involved in green roof products as an additional value added business in 2001 when a customer asked for a specific soil to grow green roof plants. At that time, little was known in the United States about what made up a proper green roof media, but through research by both LVS and the customer, Laurel Valley produced and sold its first order. Over the next three years, the United States green roof movement moved at a snail's pace, with green roofs being installed on a job-by-job basis and with all of the components, including the media, being produced on a custom basis. This type of approach translated into expensive systems for both the installer and the customer.
In 2004 LVS saw an increase in its green roof media business, and decided it was time to improve on its current green roof media design. At the same time, Peter Phillipi and Jorg Breuning came from Germany to the United States with the hope of using their more than 45 combined years experience in green roof design, installation and maintenance to build their business, Green Roof Service LLC (www.greenroofservice.com). The consulting company is based in Maryland. They were also looking for someone to partner with to create a quality green roof media similar to what they had always used in Germany. As luck would have it, LVS and GRS joined forces and created Skyland USA, LLC in 2004.
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Skyland manufactures its rooflite[TM] products that incorporate mushroom compost/spent mushroom substrate into the mix from its blending site in Avondale, PA. Plants need a specialized soil since they are not grown in the ground. This green roof media has received certification from the German FLL Green Roof Guidelines and also meet all of the current standards developed by ASTM, the acknowledged state of the an standard for the green roof industry. Using the proper growing medium is crucial for the success of any green roof system. When the growing medium is of poor or inferior quality, plants cannot thrive and the system will ultimately fail. With licensed blenders in all of the major green roof markets in the United States, rooflite[TM] certified green roof media has been used in projects ranging from a few thousand square feet up to those that are 40,000 square feet and larger.
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Components of rooflite[TM]
The rooflite[TM] product is an engineered soil that both mimics and improves on the properties of native soil. Native soil is the product of a natural process that has occurred over thousands of years. Although native soil works perfectly in its natural environment, it cannot be used on green roofs due to its excessive weight, inability to retain sufficient moisture as well as its inability to drain excessive amounts of moisture properly.
Green roof growing media faces several additional requirements since it ultimately must promote plant life in an environment that is very different from the natural surroundings of plants. An ideal growing medium should support plant growth, be lightweight, and should retain and drain water simultaneously. It also must perform all of these functions in an extremely shallow system.
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All rooflite-licensed blenders are required to use compost that has been tested under the U.S. Composting Council Soil Testing Assurance (STA) program. This is done to insure that only high quality compost products are used for the organic component in its product line. At the LVS location (the blender for rooflite[TM] in the Mid-Atlantic area) mushroom compost is used. As a general rule of thumb, green roof media products contain a 20 percent (volumetrically) addition of organic matter in their makeup.
Plant selection, depth of growing medium, regional climates and project specific factors are crucial for the long-term success of plantings on green roofs. With the proper growing media at two to four inches, hardy succulents like Sedum and Delosperma species do well. At five inches or more, hardy perennials, grasses shrubs and evergreens will work.
Transporting rooflite[TM] or other types of green roof material on-site include cranes, conveyor belts or blower trucks. Many factors have to be considered in order to find the best option for a specific project including height and size of the building, accessibility of the roof size, and design of the green roof as well as other criteria, which can influence on-site transportation.
Conclusion
As the green roof industry grows in North America, Skyland hopes to continue to build its network of licensed rooflite[TM] blenders to service the trade. (Contact Skyland if you are interested in becoming a rooflite[TM] blender in the following geographic locations: Texas, Florida, Colorado or Arizona.) Potential growth in the green roof sector is mind boggling, considering the fact that on an annual basis, Germany installs upwards of 160 million square feet, while in the United States last year, approximately 10 million square feet of green roofs were installed. The major drivers without question are the benefits of storm water management and energy savings. The major roadblock is the cost. As time goes on and more green roofs are installed, competition will build, and overall cost for green roofs will decline. This should result in a situation where the North America green roof market will match our German counterparts in number of green roof installations.
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Joe DiNorscia Laurel Valley Soils
705 Penn Green Road Landenberg, PA 19350
http://www.skylandusa.us
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