Illinois, and specifically Chicago, is fast becoming the green roof epicenter of the United States. Progressive ordinances have emphasized the importance of green roof systems to the environment and the buildings they inhabit.
Green roofs are vegetated roof covers, with plants taking the place of bare membrane, gravel ballast, shingles or tiles. All green roofs include a waterproofing layer, drainage, and plants covering the roof surface. Some green roofs contain their own irrigation systems.
Properly designed and maintained green roofs regulate temperature fluctuations inside buildings, mitigate urban heat islands, control storm water runoff, reduce erosion and pollution, create a wildlife habitat, and double the service life of the roof. To maximize these features a green roof should be installed by individuals or contractors who understand how to properly install and maintain plant material.
There are two primary types of green roofs; extensive and intensive systems.
- Extensive – have thinner and fewer numbers of layers. These require less maintenance. Extensive green roofs are lighter and less expensive. Extensive green roofs work better when there is limited human access to the green roof. Plant material should be selected that is tolerant of extreme heat, cold, wind, frost, and other atmospheric conditions. Extensive green roofs usually can work on either flat or sloped roofs. Extensive green roofs are sometimes referred to as tray or mat systems.
- Intensive – resemble traditional roof gardens and employ a wider variety of plant material since more room and depth is reserved for the plants. Other landscaping features such as water features, ponds, gazebos, pergolas, etc. may be used. Intensive green roofs are more popular when there is frequent human access (including visual access) to the roof. Intensive green roofs have greater maintenance requirements because of the wide variety of plant material used. Intensive green roofs work better on flat roofs.
One of the greatest misconceptions of a green roof is that it's maintenance free. This is not accurate. Every green roof needs to be maintained. Green roof plant material can die, become diseased, blow away, or serve as a harbinger for invasive species. Semi-annual maintenance will allow a qualified landscape contractor to look for invasive weeds, disease, tree seedlings, etc. Even element resistant plant material can die and needs attention to ensure the long term viability of the green roof. A green roof is pointless if it becomes a brown, dead roof over time.
This varies from region to region and type of system. Be prepared to pay $15-25 sq. ft. for an extensive system and $30-45 for an intensive system.
Landscape contractors are the natural installers and maintainers of green roofs. It is essential that you ensure the contractor has done green roof installation before and will use OSHA-mandated safety procedures for rooftop work. Using a landscape contractor allows for both installation and maintenance to be done by the same company. It adds cohesion when the maintainer of the plant material knows exactly why a certain type of plant material was used. Green roofs are horticultural products. Do not let other types of contractors tell you differently.
A green roof is a wonderful gift you can offer to the environment. However, green roofs must be installed and maintained by landscape contractors to ensure they survive the harsh elements of Illinois. It is not worth the cost or time to install a green roof if the contractor does not understand plant material. Give yourself peace of mind and use a qualified landscape contractor.
ILCA Contractor Directory
The following companies have sent employees through green roof safety training that satisifes the OSHA mandate for rooftop work.
- Aspen Lawn and Landscaping
- Atrium Landscape
- Christy Webber Landscapes
- Cooling Landscape Contractors, LLC
- Countryside Industries, Inc.
- Damgaard Landscape Management, Inc.
- F. Garcia Landscaping
- Great Lakes Landscape Co., Inc.
- Hayden Landscape Contractors
- Intrinsic Landscaping, Inc.
- Joe Cooling and Sons, Inc. Sod Farm
- Kinsella Landscape, Inc.
- Krugel Cobbles, Inc.
- Landscape Concepts Management
- Landworks Ltd.
- Moore Landscapes, Inc.
- Otto Damgaard Sons, Inc.
- Pedersen Company
- Robert Ebl, Inc.
- Schmechtig Landscape Company
- Sebert Landscaping
- Sexton's Landscape Concepts inc.
- SiteWorks Construction, Inc.
- Tandem Landscape Company
- The Brickman Group
- Thornapple Landscapes, Inc.
- Twin Oaks Landscaping
- Walsh Landscape Construction, Inc.
- Wingren Landscape