We just wrapped up a green roof job in East New York. Here is a photo essay from start to finish. We planted late in the year and the nights were already freezing. But we trusted the hardiness of sedum and so far they have shown to be very happy on the new roof.
The roof was your typical lifeless petrochemical slab with about six layers of tar.
The first thing we had to do was remove the tar roof. It was at the end of its life and starting to become too heavy for the house. We then built a little one foot wall around the perimer to hold the future green roof.
We had our share of nightmare weather and leaks.
We then put five layers of salvaged polyiso for a R60 roof. The materials we use is very important. We salvage as much as possible. We also didn’t want to use the conventional method of gluing the boards, which is really toxic. Below you can see a great alternative we did where we tied the insulation down with string – a very low embodied energy low toxic solution that is strong enough against the powerful winds in that area.
We then put a layer of rubber epdm, which isn’t exactly a green product but it lasts about four times longer than tar so it is pretty amazing.
The key to a green roof is that you recreate the qualities of the ground but with much less depth and much lighter. You accentuate the drainage and water retention qualities by using drainage layers and retention layers. You keep it light by using high nutrient growing medium with a lot of light filler.
Next we put a water drainage layer. It has a mesh that makes a space for the water to drain.
We salvaged the drainage layer from Build It Green but didn’t have enough so we bought another kind from the store. This one instead of a plastic mesh it has little dimples that create space for the water to drain.
Next we put the water retention layer. We got that from our friend Atom who had some left over from her jobs. The water retention layers are like big soft blankets.
Next we laid the soil all over at 3″ depth. We used Gaia Soil. It is cool because it uses recycled Styrofoam. I have my reservations about surrounding ourselves with yet more plastic….but it is salvaging huge amounts of garbage from the dump.
Here is the staging area.
Gaia soil is so light that it easily blows away so once the soil was down we covered it with jute. Over time the jute decomposes but by then the roots are holding the soil down.
Over the jute we put an inch of organic locally made compost. This holds the jute down as well as keeps the plants healthy.
On top of all this we put mulch. The mulch holds the layers down as well as gives some protection for the plants from the harsh climate up there on the roof. It also looks very dramatic! We salvaged our mulch from a garden center that was throwing it away. A rat had made its home in the pallet of mulch and they couldn’t sell it. I saw the rat as I was carting the bags away. I apologized for taking his home. Notice the gnaw holes in the bags.
Finally we bring the plants. We got our plants from two places. The first is a garden center that was throwing plants away because they had become too ugly for customers to buy. We don’t mind ugly. We love all plants even the ugly ones. We let the plants sit over the summer in a very hot and dry environment because we had no other place to put them. Because they were not your typical green roof sedum it was a great test to see which ones can handle a hot and dry green roof. Here they are when we got them.
The other plants are your typical sedum. We buy them from a local psychiatric center whose patients grow plants as part of their therapy. An employee approached Eco Brooklyn asking if we would be willing to buy the plants. Management is trying to cut funding for the gardening program but if it makes money they agreed not to cut it. It is very warped. These poor mental patients have to prove their therapy is making a profit in order to get funding. We gladly buy the plants.
We lay the plants out on the roof and then insert the plugs into the growing medium. Around the border of the roof we put stones we salvaged from a cellar excavation. They hold the roof layers down against strong winds.
We placed some salvaged tiles as stepping stones.
And here is the finished product one day after planting.
Some of the green roof plants we installed. They are just little plugs now but will eventually cover the whole roof with a lush green cover:
Here is the green roof drain, again all salvaged materials:
As New York green roof installers with a passion for pushing green building to higher level the ingredients of a green roof are just as important to us as the end result. It is great that it is a green roof. It is also great that the soil, the mats, the plants and various other things are salvaged and recycled content, thus reversing the landfill waste and reducing consumption of new resources.
It is great that the workers were there for more than a paycheck. They loved and enjoyed the process and were proud of their accomplishment. Also great is that it is for a very modest income client. It is important to us that green building be accessible to middle income people. That is how we will make the most significant positive impact.
This is the magic of holistic building. All the parts are equally important and supportive of the whole.