What is Green Roofing?

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Busy urban areas are starting to take advantage of a previously underutilized space: the roof. Instead of plain, dark roofs that contribute to the urban heat island effect, more and more buildings in Chicago and around the country are incorporating green roofing into their energy codes to reduce energy costs, create usable outdoor space for people to enjoy, add vegetation that helps purify the air, and absorb rainwater.

What Is Green Roofing?

A green roof is a layer of soil and vegetation planted over a waterproofing system installed on a flat roof. These roofs must be carefully designed with specific layers to support plant life and protect the building, including layers for structural support, waterproofing, drainage, and more.

As an alternative to a traditional roof, green roofing serves a number of purposes. It helps insulate the building, which reduces the load on the HVAC system. Not only does that help the building save money on energy, it also prolongs the life of the heating and cooling system. During a storm, up to 90 percent of the water is used by the plants and returned to the atmosphere via evaporation, rather than running off the building and into the sewer system. As mentioned previously, green roofs also reduce the urban heat island effect and create a more beautiful city.

How Green Roofing Works

There are three loosely defined types of green roofing:

• Intensive: These are rooftop parks or gardens that can support up to 150 pounds of vegetation per square foot. They often include walkways, benches, trees, and more, and require a complex system for support, irrigation, and root protection.
• Extensive: These are simpler, lighter installations supporting up to 50 pounds of vegetation per square foot. These aren’t designed to be used by the public, and instead function as an aesthetically pleasing, environmentally beneficial space. They can be installed on a slightly sloped roof and require little maintenance.
• Semi-Intensive: This in-between type of green roof may feature both extensive and intensive elements. Chicago’s own City Hall, one of the better-known green roofs, could be considered semi-intensive.

All three types offer many of the same benefits, including improved air quality, building insulation, and more.

Benefits of Green Roofing

The extensive benefits of green roofing have been enjoyed in Europe for years, and slowly the United States is catching up to the realization that installing a green roof is an investment that pays off in many ways.

• Sustainability: Improved building insulation reduces the load on the HVAC system, which prolongs its life, saves replacement costs, and keeps roofing debris out of the landfill. Green roofs are often built with recycled materials, and they reduce stormwater runoff.
• Reduced Energy Costs: The vegetation on a green roof absorbs heat and cold, which enhances the effectiveness of the insulation installed, which in turn can reduce your energy costs.
• Aesthetics: Vibrant green roofs are more interesting and attractive than traditional roofing, and they contribute to the beautification of a city.
• Reduced Maintenance: Even though plants and vegetation require regular maintenance, the roof membrane is protected by the plants, which helps it last longer and reduces your roof maintenance costs.
• Stormwater Management: A green roof can absorb up to 90 percent of rainwater in the summer and up to 40 percent in the winter, reducing the strain on the sewer system.
• Waste Diversion: Longer-lasting roof membranes and HVAC systems reduce the waste that ends up in landfills.
• Improved Air Quality: Plants help moderate the temperature and filter dust and noxious gases.
• Fire Retardation: Certain species of plants are drought resistant and hold on to water for a longer period of time, making them less prone to catch fire.  Also, the irrigation systems many green roofs require can aid in the prevention of a roof fire spreading
• Noise Reduction: An intensive green roof can reduce outside noise by up to 50 decibels.

Solutions by Knickerbocker Roofing & Paving Co. Inc.

Green roofing systems are the future. Though their installation requires careful planning and engineering, the long-term benefits serve residents and visitors, the building owners, the environment, and the community as a whole. At Knickerbocker Roofing & Paving Co. Inc., we install green roofs ranging from 1,000 to 1,000,000 square feet, backed by 135 years of local experience in the roofing industry and a manufacturer’s full system warranty. Contact us to learn more about our innovative solutions and how we can help you transform your roof, or request a quote today.