You want to put mother eff’ing PLANTS on top of your ROOF??? You cray.
Yeah, that’s what I constantly heard when we talked about green roofs but sometimes you gotta look at the science and see if it’s an overall add or a delta and depending on your perspective and research, you pick the one that confirms with all your values, and of course the codes lol
First I had to build the foundation which was basically 2×6’s on those preformed rhombus-prism concrete looking things. Then the flooring was just 1/2″ green plywood and then I started the framing which was regular 2×4’s @ 16″. Then the part that you came for… THE GREEN ROOF!!
I might have both over-engineered and over-worked the green roof like I went through and made sure there was absolutely nothing sticking up. Like I sanded the whole damn plywood sheathing. After that, I put on filter fabric for further protection of the pond liner and used permanent weather tape to seal it all together. Onwards, I put on the 20 mil ponder liner and cut a hole and waterproofed for the downspout (this was extremely stressful lol). I then added on a layer of 1″ washable HVAC air filters as my drainage layer. My thought was that it will allow for the same capillary action that a typical commercial drain mat would have. The next step was to put on another layer of filter fabric to act as a root barrier and also to keep the soil mix from clogging up the drainage layer. After that I carried up buckets of the planting mix which was 75% perlite and 25% potting soil. Lastly, I planted the roof with as many species of sedums and stonecrops that I could. I believe I bought the entire stock of Oregon stonecrop at Portland Nursery lol