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What's a Green Roof?

A "green roof," simply put, is a roof that has been turned into a garden. Unlike a simple "rooftop garden," where the garden is in containers or only takes up a small patch of the roof, with a green roof, the garden covers the entire roof. The roof gets sealed and covered with a waterproof membrane, something that facilitates vegetation (like soil) is spread and vegetation gets planted. Some people choose to build rooftop ponds to help them treat their grey water. This is another type of green roof.

You know you want one!
What Are Some of the Benefits of a Green Roof?


    • A green roof can help you save money. It helps to insulate the top of your house, which keeps heat from escaping during the winter, which helps you regulate your power bills.


    • It can help filter pollutants and carbon dioxide out of the air, which cuts down on diseases like asthma.


    • It acts as a noise barrier, which helps keeps outside noise out of the house.


    • It can act as a filter for rainwater, reducing the amount of pollutants in it.


    • It protects the actual roof of your house, which means that the roof won't need to be repaired or replaced as often.


    • In some places, like New York City, putting in a green roof is a tax write off.


    • Because the roof absorbs rain and storm water, it has the potential to reduce your need for complicated and expensive runoff drainage systems.

A few years ago, the majority of the green roofs were being installed on larger structures like apartment buildings, parking garages, corporate structures, etc. Now, though, more and more homeowners are getting in on the act. Before you start shoveling sod onto your roof, though, there are some things you need to know.

Green roofs are incredibly heavy. They have to be in order to accommodate the weight of the vegetation, the materials used to grow it, and the irrigation systems that need to be put in place to help keep the roof healthy.

Not the right type of green, but the metaphor is still applicable.

Changing your roof over from a "normal" roof to a green roof is expensive. Ten years ago, estimates started at $10 per square foot for simpler types of green roofs and go up to around $25 for more extensive projects. Add onto that a couple of dollars per square foot per year to accommodate maintenance fees. Imagine what the costs are now!

Green roofs take work to maintain. It's not the same as going out and mowing your lawn. Extensive care is required for every level of the roof -- not just for what grows out of it.

That said, when you consider the financial benefits and environmental benefits of turning your roof green, it's not hard to see how it all evens out.

If turning your roof green is still something you are determined to do, then it is time to start researching professional installation experts. Even if you have contracting experience, this is not a project you will want to attempt to do yourself. It is going to involve extensive renovation to your home to help accommodate the new (much heavier) roof that is going to be added to it. Beyond that, you're going to need to hook up irrigation systems and figure out what you want to grow. Make sure you work with certified contractors who understand how green roofs are installed and grown.

Good luck!

Erin Steiner writes full time from her home in Portland, Oregon -- one of the greenest cities in the country. She has profiled important players within the business and finance industry (like Gary Crittenden) and has written about topics ranging from small business to environmental issues to pop culture.