Laying down the foundation for my rooftop garden
Posted 10.22.2009 at 3:34 pm
6 Comments
Insulated Roof The roof with the first layer, the tapered insulation, in place. The slope goes from 6.5 inches to 1/4-inch to direct water to the scuppers, essentially drains that channel runoff to pipes.
John B. Carnett
Why bother with an unsightly and inefficient flat tar roof when you can look out the window at a teeming green garden? That's why I'm turning part of my roof green. I'll post more detail about what I'm growing and the DIY tray-based system I'm growing plants in, but before any of that can happen, the roof itself needs to be prepared to hold several inches of dirt without collapsing or flooding my upstairs. For that, I went with a multi-layer system: insulation, rigid roof board and a thermoplastic barrier. Read on for more about the installation and check out the gallery for shots of the roof-prep in action.
I hired a commercial roofing company to take my flat roof system and get it built up to accept my green roof trays. Prior to the roof crew coming, I’d prepared a series of nine-inch-high curbs, made out of 2x4’s and scraps of the ZIP board I put over the Kama panels. These curbs would hide the edges of the tapered insulation, allow for a wrap around of the thermoplastic layer, hide the edges of my green roof trays, hold my metal caps and be the top most edge of my hemlock siding.
The guys apply the tapered insulation by screwing it to the metal in the Kama panels. Then they glue the Dens Deck to the insulation, glue the TPO to the Dens Deck and finally use high powered heat guns to weld together all the seams.
The final product makes for a highly durable system that can directly support green roof trays. The multi-layer system costs about $3 more per square foot than a standard flat roof but will really hold up to the abuse of a green roof.
Click here to launch the gallery.
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other than the obviouse space saver, what are the advantages of putting a garden on your roof versus an open area on the ground? and how will you deal with erosion caused by water, growing roots, and things like that. Just curiouse.
I´m not sure about the drain. "The slope goes from 6.5 inches to 1/4-inch to direct water to the scuppers, essentially drains that channel runoff to pipes."
Well, usually there sooner or later will be leaks when you have internal drain. Clogging can´t be avoided in the long run. Then you will have leakage as the water pressure will increase becaus of the depth at the deepest part of the roof.
Maybe you would be better off with a drain that can´t be clogged over the years. I think you need a "safe failing" option. If you lower the "wall" in the deepest part of the bassin, water will overflow if/when the drainage pipe is clogged. Actually you dont need drainage pipe at all. You might be better of with drainage via a scupper with a chain directing the water to the ground. On the ground you have some nice stones for good looks and to avoid splatter.
Eric- A green roof reduces the temp on the roof in the summer and insulates it in the winter, it's great to look at, provides storm water management and new wildlife habitats...
Staff Photographer
Popular Science Magazine
jorkelman- The green roof areas all flow to scuppers that are cut into the curbs- I did not show that part of the process in the image gallery- The curb cuts have scupper boxes sitting outside the curbs and the water flows to modular water storage containers...
Staff Photographer
Popular Science Magazine
Forfilling my inner saucer girl! LOL
CONGRATS on the roof! You're using an old tradition from Europe that has been used for the lst several hundred years. It's beautiful, and serves a very basic need, insulation. Good for you! Oh and hello John, it's only been 20yrs! LOLOLOL
Forfilling my inner saucer girl! LOL
CONGRATS on the roof! You're using an old tradition from Europe that has been used for the last several hundred years. It's beautiful, and serves a very basic need, insulation. Good for you! Oh and hello John, it's only been 20yrs! LOLOLOL