I used to write a column for the local Greenville Journal called "Soil Therapy" and this is one such article: https://greenvillejournal.com/2016/07/06/sprouting-joy-living-roof/
Rooftop farms. Rooftop gardens. Living roofs. Green roofs. Roofs with gardens. There are myriad options out there with just as many names. Three years ago, I was a part of a group of young idealists who came together and introduced Greenville to rooftop farming. This was on the grander scale of the spectrum; however, you, the homeowner, can still reap the benefits of installing a green roof on your home, a garden shed or even the dog’s house.
One of the many benefits of having a green roof is reduced heating and cooling costs, as it adds an insulating layer above the roof protecting it from the sun’s heat. Research published by the National Research Council of Canada shows that this resulting insulating layer can easily cut your summer air conditioning demand by 75 percent. In the winter months, it’ll help cut the heat lost through the roof as well. Imagine your attic being cooler in the summer and warmer in the winter all due to some plants growing on your roof.
A green roof also protects your roofing from the sun’s UV rays, adding another 15 to 20 years to the lifespan of your shingles. A green roof will increase a home’s marketability and increased property value due to the higher efficiency.
Before installing a green living roof onto your existing home, you should have the roof structure checked by an engineer to see if it can withstand the extra weight load associated with the addition of the growing medium and water retention. If you are building a new home, it can be engineered and constructed appropriately to withstand the extra weight.
I would understand if you are not inclined to spend the money to green your home’s roof, but perhaps you can add a living roof to a garden shed or a doghouse. When I built a garden shed this spring, the idea was to create something that was not visible from the street. Using a barn-gray siding and a living roof hides it from neighbors and the street. The added benefit has been a respite from the heat — the inside of the shed is almost 15-20 degrees cooler than the outside climate. A traditional shingle would absorb heat and transfer it to the inside the structure. If you have an outside house for your dog, this is also a great solution.
The shed roof contains a variety of sedums — slow-growing heat and drought-tolerant plants that are perfect for this type of installation. They come in trays at big-box hardware stores. To make my dollar go further, I separated the sedums inside the trays in half and planted the other half in another tray. I then filled the empty half with a lighter soil medium that allows the sedums to spread over time. Underneath the trays I used an aluminum foil and tar flashing material (commonly used to seal around windows and doors) to waterproof the roofing surface.
Around the edges of the roof is a piece of white vinyl lattice with drains at each corner of the roof. The living roof added approximately $45 onto the total cost of the roofing materials, but in the end it makes the birds, beneficial insects and, most importantly, my Master Gardener mom much happier.