What is a “Green Roof”?

For those in the know, a “green roof” is not a roof covered in green shingles or aged copper. A green roof is something that is gaining popularity for those who want to “go green” in terms of creating more eco-friendly houses and cities.

So what is a “green roof”? A green roof is a roof that is partly or completely covered with vegetation and soil. This sits on a waterproofed membrane to keep water from entering the building. Some green roofs also might include irrigation systems. Basically, it is a vegetated, living roof.

Green roofs are not a new invention. In fact, prairie families that lived in sod houses back in the 1800’s commonly had houses excavated into hillsides where the roof of the house was basically part of the hillside. Modern green roofs are sophisticated assemblies of tough and reliable materials that can withstand water, weight, and the acids generated by vegetation. There are also special types of plants that are used, which are hardy, have fibrous roots to hold soil in place, and are able to tolerate conditions found on roof tops with only a few inches of soil.

Although there are many advantages of a green roof, a couple that impact a cityscape are that:

1. They reduce the “heat island effect” or heat that is reflected from vast expanses of roof and concrete in urban environments.
2. Reduce water run off because rainwater remains in the soil on the roof and nurtures the plants growing there.
3. They can increase your roof’s insulation value.

If you think this is some kind of “hippie” notion, think again. Many big cities, like Chicago, are encouraging residential green roof construction, even putting it on civic rooftops. If you are an eco-conscious homeowner or home buyer, a green roof is definitely something to consider and there are many sources on the Internet you can go to find out more about them and how they work.