There will come a time soon when if you walk outside and scan the horizon, you’ll see tranquil green gardens as far as your eyes can see, not the drab brown and black rooftops we see now. Everyone will have grasses, natural vegetation, and flowers on the top of their homes, sprouting and changing colors with the seasons and attracting birds, butterflies, and endangered bees to flourish in their new rooftop habitats. Even commercial buildings will have green roofs, with full trees, water gardens, and organic fruits and vegetables produced in space that is wasted now.
Thanks to these green or “living roofs,” there will be less pollution, cleaner air, less water waste, less noise pollution, and our energy costs to heat or cool our homes will be lower.
Does it sound like something out of a futuristic sci-fi society – or only for the ultra modern homes of the super wealthy? In fact, living roofs and already here and being used around the world, growing fast in popularity as we better understand and focus on the consequences of our mass ecological footprint.
In this blog, we’ll cover some of the basics of living roofs (and living walls.) In part 2, we’ll go into the amazing benefits in detail and also outline the installation and maintenance process if you wanted to add one to your home!
What are living roofs?
Green roofs, also called living roofs, is when a residential or commercial building has a specially constructed micro ecosystem of grasses and vegetation installed as the top layer on its roof surface. The roof can be flat, sloped, or pitched just like any roof. But instead of using a top layer of shingles, slate, rubberized membrane, or other traditional roofing materials, vegetation is grown in a thin layer of topsoil or organic medium that lies on top of waterproof sheeting.
There are also living walls, which can be incorporated into horizontal living spaces large or small, indoors or outdoors. Living walls are usually either grown from specialized posts that hang affixed to the walls, with plants growing up a climbing net, trellis, or similar structure, or grown right out of an organic membrane that hangs on top of regular sheetrock and includes specialized irrigation and drainage. For the purposes of this blog, we’ll include living walls whenever we say living roofs or green roofs.
There are terrific benefits to living roofs and living walls, both for the homeowner or resident, the immediate neighborhood or city, and to the ecosystem of our world as a whole.
Why are living roofs so important?
You only have to turn on the television to hear calamitous reports of climate change, global warming, and draught. And as our world gets more populated, our urban areas become more dense, with more buildings and pavement and less trees, grassy areas, and natural habitats. Rivers and waterways are more polluted than ever and at the same time, human beings are toxifying the environment to the point where other species of animals are being killed off or crowded out.
But every building has a roof, which becomes completely wasted space 99.9% of the time. The good news is that not just environmentalists and scientists but the average person is starting to understand the mutual benefit to installing solar panels to capture energy and lessen their environmental impact. Or now, living roofs.
Living roofs have some amazing benefits to the environment, and with almost 120 million homes (or households) in the U.S. alone, and countless other large commercial spaces, imagine the positive impact if they were all utilized to “green” our society.
Where can living roofs be found?
Living roofs may seem ultra-modern, but they’ve been used for over 1,000 years around the world, from the Vikings with turf living roofs in Scandinavia to traditional living roofed cottages in Ireland and Scotland.
Germany has been very progressive with clean energy and clean environmental practices, already having used living roofs for 30 years. The German government encourages Green Roof building through their Federal Nature Protection Ac as well as building codes and incentives. In nearby Austria, cities like Linz mandate green roofs for new residential and commercial buildings over a certain size. The UK has been experimenting with green roofs, anchored by the living roof atop the notable Rolls Royce showroom. And in Australia, living roofs are starting to take hold and grow in popularity.
In the United States, living roofs are still rare – mostly seen only in ultra modern and luxury, cutting-edge architecture. But already in many cities like New York, Chicago, and San Francisco, the idea of rooftop gardens on urban buildings is becoming prevalent, a precursor to familiarity and comfort with living roofs.
What kinds of living roofs are there?
There are generally two types of living roofs; intensive and extensive.
Intensive living roofs have deeper soil and can support all sorts of large vegetation up to the size of full trees. Most rooftop gardens are intensive roofs.
Extensive living roofs have a much shallower growing surface that hosts groundcover vegetation like grasses.
Of course, there are all sorts of rooftop gardens where people grow flowers, fruits and vegetables. Those may have similarities but usually are built separately and after the fact on top of a traditional roof, not incorporated into the roof itself.
What kind of vegetation do living roofs use?
There are different kinds of grasses and vegetation commonly used in living roofs. What you use depends on your climate, what plants are native to your terrain, how much rain and sunlight you get, and how deep the soil or growth membrane is on your roof.
When first setting up a living roof, installers and homeowners usually plant at least four different grasses for several reasons. Some of them may not take root or flourish so it’s good to have several varietals. And with different kinds of grasses or vegetation, you’ll have different blooming times and colors during different seasons.
So living roofs usually look like wildflower meadows, not tightly cropped short grass on our front lawns (which isn’t healthy and takes much more water.)
Tune in for part 2 of this blog, with the benefits of living roofs as well as information on installation and maintenance.