An unexpected benefit of a green roof
My office sits on top of half of our garage, which has a flat roof, so I look out on the roof of the other half of the garage. I had always been intrigued by green roofs, so that seemed like an obvious place to try one out, because I could see the roof in all of its changing beauty through the seasons, and I could easily access it (through the window) for occasional weeding. (It also helped me get a LEED point, as a wrote about in my blog.)
We used the Live Roof System that partners with local nurseries, who then grow the plants ahead of time in 2'x1' trays, so the trays can be easily placed on the roof — and look good immediately. Besides it being a beautiful garden of blooming sedum, though, it has many green benefits that I have often touted.
First, it helps insulate the roof, meaning less need for healing or cooling in the space beneath it. (In our case it's our garage, which isn't that important for keeping warm or cool, but it's still a benefit.)
Second, it reduces the heat island effect — making it much cooler than it would have been had there been a typical black EPDM roof membrane. So, it reduces the need for cooling in my office.
Third, it reduces the storm water run off, which helped contribute to a lower water bill (the city of Minneapolis will credit your storm water fee if you can prove that the water on your property basically stays on your property and does not over load the storm water sewer system). It's also just nice that there are no gutters pouring out water when it rains (it's more like a trickle), so there is no erosion or annoying splashing at the bottom of the gutter.
Finally, and this is the usually the biggest financial benefit, green roof extends the life of the roof by 2-3 times. We moved into our home two years ago, so I figured I had a good 12-15 years to test this out. However, Minneapolis suffered a serious hailstorm back on May 10, which significantly damaged our roof — everywhere except where the green roof is! The plants protected the roof from the hail, and survived themselves. So, while the rest of roof needs replacement (insurance mostly covers it, but it is still a huge hassle), our green roof gets to stay put. A very unexpected — and early — benefit a green roof!
Melissa Rappaport Schifman Melissa provides sustainability consulting services for businesses in the Twin Cities metropolitan area. Melissa is also the founder of Green Intention LLC, where she writes and blogs about her experience in getting her own home LEED Gold certified--and then trying to live more sustainably in the home. She chairs her congregations Task Force for Sustainability, has her MBA, Master's in Public Policy, and is a LEED AP for Homes. www