Every week I am bombarded with all sorts of information about roofs and roofing. It comes from all four corners of the world. A few weeks back I caught a story right around the corner from me at the campus of the University of Georgia, in Athens. My grandson, Joey, was born in Athens a few days after this story hit the wires. One has nothing to do with the other; I just cannot resist the mention of our newest family member. He is a handsome little guy and I am pretty sure he is smart, too.
Check out this article – http://onlineathens.com/local-news/2012-04-21/five-years-uga-rooftop-garden-flourishing. This is one of the many featured articles relating to all things green — including green roofs — that are all over the media these days. So what caught my eye in this piece? Here is the quote:
“In the past 50 years, nobody bothered to gather data on how the roof affects heating and cooling in the geography building, Adams said. But the roof has no leaks or structural damage, and has never been repaired. Most roofs require extensive maintenance every 10 to 15 years.”
50 years? This is one of very few “garden roofs” that are this old. There are many older gardens and grassy fields over built spaces, but they are mostly referred to as waterproofing projects, not roofs.
Frankly, I am not amazed at the performance on this roof. If you start off with a sound roof structure covered by a robust, watertight membrane and then cover it with insulating soil topped with vegetation, what is there to degrade the membrane? Solar radiation: gone. Thermal shock: non-existent. Movement from wind and other natural forces: fuggitaboutit.
This is the kind of evidence the world will need to see to advance the move toward the garden roof concept. There are so many more reasons to take construction in this direction, but sustainability and cost savings is a great place to start. The roofing system, no matter what it consists of, must deliver a great value proposition. Compare 50 years to the average 17 years a low-slope roof will last in this country and you can spend a lot more on the garden. You may have to toss in some points for superior insulating qualities, but what the heck.
There is one more thing holding back the garden roof, and that is volume. No matter what we do in construction, once we get good at it the cost comes down. I am confident that garden roofing has a bright future and that it will improve in ways that will delight designers and owners alike. Roofing contractors who install these systems will do well as the market continues to expand.
And by the way, it is only the first 50 years. According to this report, the system continues to perform just fine.