What is the most cost-effective way to make your roof green?

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Home Improvement

Green Living Image Gallery Donald Braboy, a groundskeeper, works on the rooftop garden of Chicago City Hall in Illinois. The garden, which was first planted in 2000, is located on the top of the 11-story building. Pictures of green living.
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In the past, green roofs were only found in “home of the future” exhibits, but nowadays they are becoming more common on top of city buildings and regular homes in neighborhoods around the world. Technically, a green roof is a vegetative layer grown on a rooftop [source: Environmental Protection Agency]. However, planting a rooftop garden is not the only way to increase the “green” factor of that unused space on top of your home.

The rooftop garden on top of Chicago’s City Hall is perhaps the most well-known green roof in the United States. It covers 20,300 square feet (1,866 square meters) of the 38,800 square-foot (3,605 square-meter) rooftop and saves the city around $5,000 a year in utility bills [source: Green Roof Projects]. As of April 2010, almost 500 green roofs had been installed or were under construction in Chicago, making it the U.S. city with the most green rooftop square footage. However, those 500 buildings represent only one-tenth of one percent of the 500,000 total buildings in the city [source: Kamin]. In Germany, rooftop gardens can be found on 15 to 20 percent of all flat-roofed buildings, showing that the United States has a long way to go in adopting green roof practices [source: Kamin].

Despite their potential to reduce energy costs, decrease the urban heat island effect, and even provide usable land for urban farming [source: Shulman], why have rooftop gardens been so slow to catch on in the United States? One plausible reason is cost. A “green roof” in the truest sense of the term can cost anywhere from $10 per square foot for a simple “extensive” green roof composed of shallow soil and a resilient ground cover, to over $25 per square foot for a more intricate “intensive” green roof, which includes larger plants, shrubs, and even small trees [source: Environmental Protection Agency].

Rooftop gardens purify the air, enhance urban landscapes, and contribute to cooler indoor and outdoor temperatures. However, if they are beyond your budget, there are many other options available to help you make your roof green for less. Which option is best for you? Keep reading to find out!


Making Your Roof Green

To decide on the best way to make your roof green, first consider your roofing needs and what you hope to achieve. Do you want to generate electricity, manage runoff, or just cool things down? Are you replacing an old roof, building a new home, or hoping to improve the performance of an existing roof without removing or replacing it? What kind of climate do you live in? Is it more important for you to stay warm in the winter, cool in the summer, or both? Finally, how much are you willing and able to spend? Are you willing to invest more upfront for potential long-term benefits, or do you need to make do with limited financial resources?

Living in a hot climate can significantly increase cooling costs, but a cool roof can be a more affordable solution than a green roof. A cool roof lowers the surface temperature of your roof, which in turn lowers the temperature inside your home. For those with a roof that is currently black or dark-colored, consider coating or shingling it in a light color. If you have a flat or barely sloped roof, you can have it recoated in white for 75 cents to $1.50 per square foot. Alternatively, if your roof is steep, you can replace your standard shingles with a “cool pigment” shingle for 60 cents to $2.10 per square foot.

For those who prioritize reducing their carbon footprint and have no budget constraints, solar panels and wind turbines are alternative energy technologies that can use your roof’s exposure to sun and wind to generate some or all of your household electricity. However, the high cost of these technologies means that it will take years to recoup your initial investment.

If a green roof, cool roof, or solar array is not within your budget, there are still ways to put the surface of your roof to work for you. Adding a skylight is a great way to reduce energy consumption, particularly if you find yourself turning lights on during the day to brighten dark rooms. A solar tube skylight is a more affordable option that ranges in diameter from 10 to 22 inches and can brighten up to 600 square feet of living space. Traditional skylights are more expensive to install but may be eligible for tax credits.

In addition, building a rain barrel is a cost-effective way to collect rainwater that streams off your roof and reduce stormwater runoff. Rain barrels can be purchased for around $100 or made yourself with a salvaged plastic barrel and some basic plumbing fixtures.

If you’re looking to make your roof more eco-friendly, there are several options to choose from. Installing a rain barrel won’t directly cool your roof, but it can collect water to irrigate your lawn and garden. It can also help reduce pollution in streams by diverting overflow from downspouts. While a green roof may be the most expensive choice upfront, it can provide long-term savings and quality of life benefits, especially in urban areas where green space is scarce. The type of eco-friendly roof you choose depends on factors like the size and type of your roof, heating and cooling needs, and the location of your home. If you’re interested in a rooftop garden, costs may decrease as the technology becomes more widespread. In Germany, green roofs cost between 8 and 15 dollars per square foot. For more information, check out the related articles and sources listed below.


1. What is a green roof?

A green roof, also known as a living roof or vegetated roof, is a roof covered with vegetation, soil, and a waterproof membrane. These roofs are designed to absorb rainwater and reduce the amount of heat absorbed by the building, leading to a number of environmental benefits.

2. Why should I consider a green roof?

Green roofs can help reduce energy costs, improve air quality, and provide habitat for wildlife. They also help reduce stormwater runoff and can increase the lifespan of a roof by protecting it from UV rays and extreme temperatures.

3. What are the different types of green roofs?

There are two main types of green roofs: extensive and intensive. Extensive green roofs are lighter and require less maintenance, consisting of a thin layer of soil and drought-resistant plants. Intensive green roofs are heavier and require more maintenance, with a deeper layer of soil and a wider variety of plants.

4. What is the least expensive way to green my roof?

The least expensive way to green your roof is to install an extensive green roof. These roofs require less soil and maintenance, making them a more affordable option. You can also save money by using native plants that are adapted to your climate and require less watering.

5. How do I install a green roof?

Installing a green roof requires careful planning and professional installation. First, you need to make sure your roof can support the weight of the plants and soil. Then, a waterproof membrane is installed, followed by a layer of insulation. Finally, the soil and plants are added, along with irrigation and drainage systems.

6. Do green roofs require a lot of maintenance?

The amount of maintenance required depends on the type of green roof you install. Extensive green roofs require less maintenance than intensive green roofs, but all green roofs require regular watering, weeding, and fertilizing to keep the plants healthy.

7. Can I install a green roof myself?

Installing a green roof is a complex process that should only be done by professionals. The weight of the soil and plants can be a safety hazard, and proper installation of the waterproof membrane and drainage systems is crucial to prevent leaks and water damage.

8. What kind of plants can I use on a green roof?

The plants you choose for your green roof should be adapted to your climate and able to withstand the conditions on a roof, such as high winds and intense sunlight. Drought-resistant plants like sedum and native grasses are popular choices for extensive green roofs.

9. Will a green roof attract pests?

Green roofs can provide habitat for wildlife, including insects, birds, and small mammals. However, proper maintenance and monitoring can help prevent pest infestations.

10. How long will a green roof last?

The lifespan of a green roof depends on a number of factors, including the type of plants used, the quality of the waterproof membrane, and the level of maintenance. With proper installation and maintenance, a green roof can last up to 50 years.

11. Are there any financial incentives for installing a green roof?

There may be financial incentives available for installing a green roof, such as tax credits or grants from local governments or environmental organizations. Check with your local authorities to see what incentives are available in your area.

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