Green Roof Guy's Profile

Although I love the passion here for rooftop gardening, this "how-to" guide is really misleading and may set people going on the wrong path. I love the idea of urban agriculture but the truth is, roofs are difficult places to build on and a lot of care needs to go in to ensure that leaks and load bearing issues are not a problem. A number of really important steps in the rooftop garden process were not discussed in this article.

Weight load is a huge problem. Roofs are not designed to carry this extra load and the weight calculations given here are not accurate. That soil mix is much heavier than a typical lightweight green roof soil which typically includes 80 to 90% expanded shale or clay and 10 to 20% organic material. In addition, it looks like there is a lot of other stuff on that roof that would have to be included in your weight calculations.

Water is a problem. Roof membranes have a warranty. When you put stuff on top of them without using a root barrier/protection board you invalidate that warranty. In addition, roof membranes are very susceptible to cracking and puncturing and without the necessary protection layer under your trays, you will eventually create holes in your membrane and have leaks.

Step 1 - Get a Structural Analysis to verify your roof's load bearing capacity.

Step 2 - Contact your roof installer and verify that your warranty will still apply if use a protection board.

Step 3 - Get busy planning that garden! You will be an urban pioneer! I would love to see a world where we can all create localized food networks like the gardener has done here. It's very inspiring!