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 Green Roofs for Southern Landscapes
Sod covered houses were common throughout much of Europe and western North America, yet new technologies are allowing for their use on modern residential, commercial, and industrial buildings. Consisting of vegetation, a growing medium, impermeable membranes, drainage, and sometimes supplemental irrigation; green roofs offer the following benefits to a structure:
There are a number of different techniques, materials, and growing media’s that may be used on a green roof project, and may vary according to the structure. Typically, directly on top of the roof is a separation layer, followed by layers of insulation, moisture barrier, waterproofing, drainage protection, drainage, filter fabric, growing media, and finally plants. The pitch of the roof should range between 5 and 20 degrees in slope for positive water drainage. Additional drainage layers or pipes may be needed for flat roof types. According to the U.S. Environmental Protection Agency report on Green Roofs, average national costs for an extensive green roof is approximately $8 per square foot for materials, preparation and installation. Plant species that are suitable for green roofs in the Southern United States are still being researched, but the following types have been used in these regional project examples: University
of Central Florida Student Union, Orlando, Florida Charles Perry Construction Yard, University of Florida, Florida Lady Bird Johnson Wildflower Center Green Roof Research, Texas Haley Center, Auburn University, Alabama For more information on green roofs, visit the following public Web sites:
Images are available in higher resolution: Top | Bottom Written by Robert F. Brzuszek, Assistant Extension Professor, The Department of Landscape Architecture, Mississippi State University. |
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Visit: DAFVM || USDA Search our Site || Need more information about this subject? Last Modified: Thursday, 10-Apr-08 10:57:29 URL: http://msucares.com/lawn/landscape/sustainable/greenroofs.html Mississippi State University is an equal opportunity institution. Recommendations on this web site do not endorse any commercial products or trade names. |
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Green roofs are vegetative alternatives to traditional
roofing materials. Instead of having asphalt, gravel, or shingles on
a roof, live plants and growing media are placed.
Green roofs are either intensive or extensive, referring
to the soil media depth and ultimate weight upon the roof. Intensive
green roofs have growing media’s ranging from 8” to 24”, which
allow for the inclusion of larger shrubs and even trees, with weight
loads ranging from 60 to 200 pounds per square foot. Intensive roofs
require more regular maintenance and are suited to structures that can
support heavier loads. Extensive green roofs have shallower soils from
2” to 7” typically allowing for herbaceous plants and groundcovers,
and weight loads ranging from 16 to 35 pounds per square foot. This is
usually more suitable for existing roof types as it is lighter in weight.
Maintenance considerations are generally lower for extensive types. With
any green roof project, an architect or structural engineer should determine
the weight loads that the roof will support.
